diff --git a/poky/scripts/pybootchartgui/pybootchartgui/draw.py b/poky/scripts/pybootchartgui/pybootchartgui/draw.py
index 201ce45..add5c53 100644
--- a/poky/scripts/pybootchartgui/pybootchartgui/draw.py
+++ b/poky/scripts/pybootchartgui/pybootchartgui/draw.py
@@ -19,22 +19,23 @@
 import re
 import random
 import colorsys
+import functools
 from operator import itemgetter
 
 class RenderOptions:
 
-	def __init__(self, app_options):
-		# should we render a cumulative CPU time chart
-		self.cumulative = True
-		self.charts = True
-		self.kernel_only = False
-		self.app_options = app_options
+    def __init__(self, app_options):
+        # should we render a cumulative CPU time chart
+        self.cumulative = True
+        self.charts = True
+        self.kernel_only = False
+        self.app_options = app_options
 
-	def proc_tree (self, trace):
-		if self.kernel_only:
-			return trace.kernel_tree
-		else:
-			return trace.proc_tree
+    def proc_tree (self, trace):
+        if self.kernel_only:
+            return trace.kernel_tree
+        else:
+            return trace.proc_tree
 
 # Process tree background color.
 BACK_COLOR = (1.0, 1.0, 1.0, 1.0)
@@ -136,11 +137,11 @@
 # Distinct colors used for different disk volumnes.
 # If we have more volumns, colors get re-used.
 VOLUME_COLORS = [
-	(1.0, 1.0, 0.00, 1.0),
-	(0.0, 1.00, 0.00, 1.0),
-	(1.0, 0.00, 1.00, 1.0),
-	(0.0, 0.00, 1.00, 1.0),
-	(0.0, 1.00, 1.00, 1.0),
+    (1.0, 1.0, 0.00, 1.0),
+    (0.0, 1.00, 0.00, 1.0),
+    (1.0, 0.00, 1.00, 1.0),
+    (0.0, 0.00, 1.00, 1.0),
+    (0.0, 1.00, 1.00, 1.0),
 ]
 
 # Process states
@@ -152,7 +153,7 @@
 STATE_ZOMBIE    = 5
 
 STATE_COLORS = [(0, 0, 0, 0), PROC_COLOR_R, PROC_COLOR_S, PROC_COLOR_D, \
-		PROC_COLOR_T, PROC_COLOR_Z, PROC_COLOR_X, PROC_COLOR_W]
+        PROC_COLOR_T, PROC_COLOR_Z, PROC_COLOR_X, PROC_COLOR_W]
 
 # CumulativeStats Types
 STAT_TYPE_CPU = 0
@@ -160,80 +161,80 @@
 
 # Convert ps process state to an int
 def get_proc_state(flag):
-	return "RSDTZXW".find(flag) + 1
+    return "RSDTZXW".find(flag) + 1
 
 def draw_text(ctx, text, color, x, y):
-	ctx.set_source_rgba(*color)
-	ctx.move_to(x, y)
-	ctx.show_text(text)
+    ctx.set_source_rgba(*color)
+    ctx.move_to(x, y)
+    ctx.show_text(text)
 
 def draw_fill_rect(ctx, color, rect):
-	ctx.set_source_rgba(*color)
-	ctx.rectangle(*rect)
-	ctx.fill()
+    ctx.set_source_rgba(*color)
+    ctx.rectangle(*rect)
+    ctx.fill()
 
 def draw_rect(ctx, color, rect):
-	ctx.set_source_rgba(*color)
-	ctx.rectangle(*rect)
-	ctx.stroke()
+    ctx.set_source_rgba(*color)
+    ctx.rectangle(*rect)
+    ctx.stroke()
 
 def draw_legend_box(ctx, label, fill_color, x, y, s):
-	draw_fill_rect(ctx, fill_color, (x, y - s, s, s))
-	draw_rect(ctx, PROC_BORDER_COLOR, (x, y - s, s, s))
-	draw_text(ctx, label, TEXT_COLOR, x + s + 5, y)
+    draw_fill_rect(ctx, fill_color, (x, y - s, s, s))
+    draw_rect(ctx, PROC_BORDER_COLOR, (x, y - s, s, s))
+    draw_text(ctx, label, TEXT_COLOR, x + s + 5, y)
 
 def draw_legend_line(ctx, label, fill_color, x, y, s):
-	draw_fill_rect(ctx, fill_color, (x, y - s/2, s + 1, 3))
-	ctx.arc(x + (s + 1)/2.0, y - (s - 3)/2.0, 2.5, 0, 2.0 * math.pi)
-	ctx.fill()
-	draw_text(ctx, label, TEXT_COLOR, x + s + 5, y)
+    draw_fill_rect(ctx, fill_color, (x, y - s/2, s + 1, 3))
+    ctx.arc(x + (s + 1)/2.0, y - (s - 3)/2.0, 2.5, 0, 2.0 * math.pi)
+    ctx.fill()
+    draw_text(ctx, label, TEXT_COLOR, x + s + 5, y)
 
 def draw_label_in_box(ctx, color, label, x, y, w, maxx):
-	label_w = ctx.text_extents(label)[2]
-	label_x = x + w / 2 - label_w / 2
-	if label_w + 10 > w:
-		label_x = x + w + 5
-	if label_x + label_w > maxx:
-		label_x = x - label_w - 5
-	draw_text(ctx, label, color, label_x, y)
+    label_w = ctx.text_extents(label)[2]
+    label_x = x + w / 2 - label_w / 2
+    if label_w + 10 > w:
+        label_x = x + w + 5
+    if label_x + label_w > maxx:
+        label_x = x - label_w - 5
+    draw_text(ctx, label, color, label_x, y)
 
 def draw_sec_labels(ctx, options, rect, sec_w, nsecs):
-	ctx.set_font_size(AXIS_FONT_SIZE)
-	prev_x = 0
-	for i in range(0, rect[2] + 1, sec_w):
-		if ((i / sec_w) % nsecs == 0) :
-			if options.app_options.as_minutes :
-				label = "%.1f" % (i / sec_w / 60.0)
-			else :
-				label = "%d" % (i / sec_w)
-			label_w = ctx.text_extents(label)[2]
-			x = rect[0] + i - label_w/2
-			if x >= prev_x:
-				draw_text(ctx, label, TEXT_COLOR, x, rect[1] - 2)
-				prev_x = x + label_w
+    ctx.set_font_size(AXIS_FONT_SIZE)
+    prev_x = 0
+    for i in range(0, rect[2] + 1, sec_w):
+        if ((i / sec_w) % nsecs == 0) :
+            if options.app_options.as_minutes :
+                label = "%.1f" % (i / sec_w / 60.0)
+            else :
+                label = "%d" % (i / sec_w)
+            label_w = ctx.text_extents(label)[2]
+            x = rect[0] + i - label_w/2
+            if x >= prev_x:
+                draw_text(ctx, label, TEXT_COLOR, x, rect[1] - 2)
+                prev_x = x + label_w
 
 def draw_box_ticks(ctx, rect, sec_w):
-	draw_rect(ctx, BORDER_COLOR, tuple(rect))
+    draw_rect(ctx, BORDER_COLOR, tuple(rect))
 
-	ctx.set_line_cap(cairo.LINE_CAP_SQUARE)
+    ctx.set_line_cap(cairo.LINE_CAP_SQUARE)
 
-	for i in range(sec_w, rect[2] + 1, sec_w):
-		if ((i / sec_w) % 10 == 0) :
-			ctx.set_line_width(1.5)
-		elif sec_w < 5 :
-			continue
-		else :
-			ctx.set_line_width(1.0)
-		if ((i / sec_w) % 30 == 0) :
-			ctx.set_source_rgba(*TICK_COLOR_BOLD)
-		else :
-			ctx.set_source_rgba(*TICK_COLOR)
-		ctx.move_to(rect[0] + i, rect[1] + 1)
-		ctx.line_to(rect[0] + i, rect[1] + rect[3] - 1)
-		ctx.stroke()
-	ctx.set_line_width(1.0)
+    for i in range(sec_w, rect[2] + 1, sec_w):
+        if ((i / sec_w) % 10 == 0) :
+            ctx.set_line_width(1.5)
+        elif sec_w < 5 :
+            continue
+        else :
+            ctx.set_line_width(1.0)
+        if ((i / sec_w) % 30 == 0) :
+            ctx.set_source_rgba(*TICK_COLOR_BOLD)
+        else :
+            ctx.set_source_rgba(*TICK_COLOR)
+        ctx.move_to(rect[0] + i, rect[1] + 1)
+        ctx.line_to(rect[0] + i, rect[1] + rect[3] - 1)
+        ctx.stroke()
+    ctx.set_line_width(1.0)
 
-	ctx.set_line_cap(cairo.LINE_CAP_BUTT)
+    ctx.set_line_cap(cairo.LINE_CAP_BUTT)
 
 def draw_annotations(ctx, proc_tree, times, rect):
     ctx.set_line_cap(cairo.LINE_CAP_SQUARE)
@@ -252,51 +253,51 @@
     ctx.set_dash([])
 
 def draw_chart(ctx, color, fill, chart_bounds, data, proc_tree, data_range):
-	ctx.set_line_width(0.5)
-	x_shift = proc_tree.start_time
+    ctx.set_line_width(0.5)
+    x_shift = proc_tree.start_time
 
-	def transform_point_coords(point, x_base, y_base, \
-				   xscale, yscale, x_trans, y_trans):
-		x = (point[0] - x_base) * xscale + x_trans
-		y = (point[1] - y_base) * -yscale + y_trans + chart_bounds[3]
-		return x, y
+    def transform_point_coords(point, x_base, y_base, \
+                   xscale, yscale, x_trans, y_trans):
+        x = (point[0] - x_base) * xscale + x_trans
+        y = (point[1] - y_base) * -yscale + y_trans + chart_bounds[3]
+        return x, y
 
-	max_x = max (x for (x, y) in data)
-	max_y = max (y for (x, y) in data)
-	# avoid divide by zero
-	if max_y == 0:
-		max_y = 1.0
-	xscale = float (chart_bounds[2]) / (max_x - x_shift)
-	# If data_range is given, scale the chart so that the value range in
-	# data_range matches the chart bounds exactly.
-	# Otherwise, scale so that the actual data matches the chart bounds.
-	if data_range:
-		yscale = float(chart_bounds[3]) / (data_range[1] - data_range[0])
-		ybase = data_range[0]
-	else:
-		yscale = float(chart_bounds[3]) / max_y
-		ybase = 0
+    max_x = max (x for (x, y) in data)
+    max_y = max (y for (x, y) in data)
+    # avoid divide by zero
+    if max_y == 0:
+        max_y = 1.0
+    xscale = float (chart_bounds[2]) / (max_x - x_shift)
+    # If data_range is given, scale the chart so that the value range in
+    # data_range matches the chart bounds exactly.
+    # Otherwise, scale so that the actual data matches the chart bounds.
+    if data_range:
+        yscale = float(chart_bounds[3]) / (data_range[1] - data_range[0])
+        ybase = data_range[0]
+    else:
+        yscale = float(chart_bounds[3]) / max_y
+        ybase = 0
 
-	first = transform_point_coords (data[0], x_shift, ybase, xscale, yscale, \
-				        chart_bounds[0], chart_bounds[1])
-	last =  transform_point_coords (data[-1], x_shift, ybase, xscale, yscale, \
-				        chart_bounds[0], chart_bounds[1])
+    first = transform_point_coords (data[0], x_shift, ybase, xscale, yscale, \
+                        chart_bounds[0], chart_bounds[1])
+    last =  transform_point_coords (data[-1], x_shift, ybase, xscale, yscale, \
+                        chart_bounds[0], chart_bounds[1])
 
-	ctx.set_source_rgba(*color)
-	ctx.move_to(*first)
-	for point in data:
-		x, y = transform_point_coords (point, x_shift, ybase, xscale, yscale, \
-					       chart_bounds[0], chart_bounds[1])
-		ctx.line_to(x, y)
-	if fill:
-		ctx.stroke_preserve()
-		ctx.line_to(last[0], chart_bounds[1]+chart_bounds[3])
-		ctx.line_to(first[0], chart_bounds[1]+chart_bounds[3])
-		ctx.line_to(first[0], first[1])
-		ctx.fill()
-	else:
-		ctx.stroke()
-	ctx.set_line_width(1.0)
+    ctx.set_source_rgba(*color)
+    ctx.move_to(*first)
+    for point in data:
+        x, y = transform_point_coords (point, x_shift, ybase, xscale, yscale, \
+                           chart_bounds[0], chart_bounds[1])
+        ctx.line_to(x, y)
+    if fill:
+        ctx.stroke_preserve()
+        ctx.line_to(last[0], chart_bounds[1]+chart_bounds[3])
+        ctx.line_to(first[0], chart_bounds[1]+chart_bounds[3])
+        ctx.line_to(first[0], first[1])
+        ctx.fill()
+    else:
+        ctx.stroke()
+    ctx.set_line_width(1.0)
 
 bar_h = 55
 meminfo_bar_h = 2 * bar_h
@@ -311,338 +312,344 @@
 OPTIONS = None
 
 def extents(options, xscale, trace):
-	start = min(trace.start.keys())
-	end = start
+    start = min(trace.start.keys())
+    end = start
 
-        processes = 0
-        for proc in trace.processes:
-                if not options.app_options.show_all and \
-                   trace.processes[proc][1] - trace.processes[proc][0] < options.app_options.mintime:
-                        continue
+    processes = 0
+    for proc in trace.processes:
+        if not options.app_options.show_all and \
+               trace.processes[proc][1] - trace.processes[proc][0] < options.app_options.mintime:
+            continue
 
-                if trace.processes[proc][1] > end:
-                        end = trace.processes[proc][1]
-                processes += 1
+        if trace.processes[proc][1] > end:
+            end = trace.processes[proc][1]
+        processes += 1
 
-	if trace.min is not None and trace.max is not None:
-		start = trace.min
-		end = trace.max
+    if trace.min is not None and trace.max is not None:
+        start = trace.min
+        end = trace.max
 
-	w = int ((end - start) * sec_w_base * xscale) + 2 * off_x
-	h = proc_h * processes + header_h + 2 * off_y
+    w = int ((end - start) * sec_w_base * xscale) + 2 * off_x
+    h = proc_h * processes + header_h + 2 * off_y
 
-	if options.charts:
-		if trace.cpu_stats:
-			h += 30 + bar_h
-		if trace.disk_stats:
-			h += 30 + bar_h
-		if trace.monitor_disk:
-			h += 30 + bar_h
-		if trace.mem_stats:
-			h += meminfo_bar_h
+    if options.charts:
+        if trace.cpu_stats:
+            h += 30 + bar_h
+        if trace.disk_stats:
+            h += 30 + bar_h
+        if trace.monitor_disk:
+            h += 30 + bar_h
+        if trace.mem_stats:
+            h += meminfo_bar_h
 
-	return (w, h)
+    # Allow for width of process legend and offset
+    if w < (720 + off_x):
+        w = 720 + off_x
+
+    return (w, h)
 
 def clip_visible(clip, rect):
-	xmax = max (clip[0], rect[0])
-	ymax = max (clip[1], rect[1])
-	xmin = min (clip[0] + clip[2], rect[0] + rect[2])
-	ymin = min (clip[1] + clip[3], rect[1] + rect[3])
-	return (xmin > xmax and ymin > ymax)
+    xmax = max (clip[0], rect[0])
+    ymax = max (clip[1], rect[1])
+    xmin = min (clip[0] + clip[2], rect[0] + rect[2])
+    ymin = min (clip[1] + clip[3], rect[1] + rect[3])
+    return (xmin > xmax and ymin > ymax)
 
 def render_charts(ctx, options, clip, trace, curr_y, w, h, sec_w):
-	proc_tree = options.proc_tree(trace)
+    proc_tree = options.proc_tree(trace)
 
-	# render bar legend
-	if trace.cpu_stats:
-		ctx.set_font_size(LEGEND_FONT_SIZE)
+    # render bar legend
+    if trace.cpu_stats:
+        ctx.set_font_size(LEGEND_FONT_SIZE)
 
-		draw_legend_box(ctx, "CPU (user+sys)", CPU_COLOR, off_x, curr_y+20, leg_s)
-		draw_legend_box(ctx, "I/O (wait)", IO_COLOR, off_x + 120, curr_y+20, leg_s)
+        draw_legend_box(ctx, "CPU (user+sys)", CPU_COLOR, off_x, curr_y+20, leg_s)
+        draw_legend_box(ctx, "I/O (wait)", IO_COLOR, off_x + 120, curr_y+20, leg_s)
 
-		# render I/O wait
-		chart_rect = (off_x, curr_y+30, w, bar_h)
-		if clip_visible (clip, chart_rect):
-			draw_box_ticks (ctx, chart_rect, sec_w)
-			draw_annotations (ctx, proc_tree, trace.times, chart_rect)
-			draw_chart (ctx, IO_COLOR, True, chart_rect, \
-				    [(sample.time, sample.user + sample.sys + sample.io) for sample in trace.cpu_stats], \
-				    proc_tree, None)
-			# render CPU load
-			draw_chart (ctx, CPU_COLOR, True, chart_rect, \
-				    [(sample.time, sample.user + sample.sys) for sample in trace.cpu_stats], \
-				    proc_tree, None)
+        # render I/O wait
+        chart_rect = (off_x, curr_y+30, w, bar_h)
+        if clip_visible (clip, chart_rect):
+            draw_box_ticks (ctx, chart_rect, sec_w)
+            draw_annotations (ctx, proc_tree, trace.times, chart_rect)
+            draw_chart (ctx, IO_COLOR, True, chart_rect, \
+                    [(sample.time, sample.user + sample.sys + sample.io) for sample in trace.cpu_stats], \
+                    proc_tree, None)
+            # render CPU load
+            draw_chart (ctx, CPU_COLOR, True, chart_rect, \
+                    [(sample.time, sample.user + sample.sys) for sample in trace.cpu_stats], \
+                    proc_tree, None)
 
-		curr_y = curr_y + 30 + bar_h
+        curr_y = curr_y + 30 + bar_h
 
-	# render second chart
-	if trace.disk_stats:
-		draw_legend_line(ctx, "Disk throughput", DISK_TPUT_COLOR, off_x, curr_y+20, leg_s)
-		draw_legend_box(ctx, "Disk utilization", IO_COLOR, off_x + 120, curr_y+20, leg_s)
+    # render second chart
+    if trace.disk_stats:
+        draw_legend_line(ctx, "Disk throughput", DISK_TPUT_COLOR, off_x, curr_y+20, leg_s)
+        draw_legend_box(ctx, "Disk utilization", IO_COLOR, off_x + 120, curr_y+20, leg_s)
 
-		# render I/O utilization
-		chart_rect = (off_x, curr_y+30, w, bar_h)
-		if clip_visible (clip, chart_rect):
-			draw_box_ticks (ctx, chart_rect, sec_w)
-			draw_annotations (ctx, proc_tree, trace.times, chart_rect)
-			draw_chart (ctx, IO_COLOR, True, chart_rect, \
-				    [(sample.time, sample.util) for sample in trace.disk_stats], \
-				    proc_tree, None)
+        # render I/O utilization
+        chart_rect = (off_x, curr_y+30, w, bar_h)
+        if clip_visible (clip, chart_rect):
+            draw_box_ticks (ctx, chart_rect, sec_w)
+            draw_annotations (ctx, proc_tree, trace.times, chart_rect)
+            draw_chart (ctx, IO_COLOR, True, chart_rect, \
+                    [(sample.time, sample.util) for sample in trace.disk_stats], \
+                    proc_tree, None)
 
-		# render disk throughput
-		max_sample = max (trace.disk_stats, key = lambda s: s.tput)
-		if clip_visible (clip, chart_rect):
-			draw_chart (ctx, DISK_TPUT_COLOR, False, chart_rect, \
-				    [(sample.time, sample.tput) for sample in trace.disk_stats], \
-				    proc_tree, None)
+        # render disk throughput
+        max_sample = max (trace.disk_stats, key = lambda s: s.tput)
+        if clip_visible (clip, chart_rect):
+            draw_chart (ctx, DISK_TPUT_COLOR, False, chart_rect, \
+                    [(sample.time, sample.tput) for sample in trace.disk_stats], \
+                    proc_tree, None)
 
-		pos_x = off_x + ((max_sample.time - proc_tree.start_time) * w / proc_tree.duration)
+        pos_x = off_x + ((max_sample.time - proc_tree.start_time) * w / proc_tree.duration)
 
-		shift_x, shift_y = -20, 20
-		if (pos_x < off_x + 245):
-			shift_x, shift_y = 5, 40
+        shift_x, shift_y = -20, 20
+        if (pos_x < off_x + 245):
+            shift_x, shift_y = 5, 40
 
-		label = "%dMB/s" % round ((max_sample.tput) / 1024.0)
-		draw_text (ctx, label, DISK_TPUT_COLOR, pos_x + shift_x, curr_y + shift_y)
+        label = "%dMB/s" % round ((max_sample.tput) / 1024.0)
+        draw_text (ctx, label, DISK_TPUT_COLOR, pos_x + shift_x, curr_y + shift_y)
 
-		curr_y = curr_y + 30 + bar_h
+        curr_y = curr_y + 30 + bar_h
 
-	# render disk space usage
-	#
-	# Draws the amount of disk space used on each volume relative to the
-	# lowest recorded amount. The graphs for each volume are stacked above
-	# each other so that total disk usage is visible.
-	if trace.monitor_disk:
-		ctx.set_font_size(LEGEND_FONT_SIZE)
-		# Determine set of volumes for which we have
-		# information and the minimal amount of used disk
-		# space for each. Currently samples are allowed to
-		# not have a values for all volumes; drawing could be
-		# made more efficient if that wasn't the case.
-		volumes = set()
-		min_used = {}
-		for sample in trace.monitor_disk:
-			for volume, used in sample.records.items():
-				volumes.add(volume)
-				if volume not in min_used or min_used[volume] > used:
-					min_used[volume] = used
-		volumes = sorted(list(volumes))
-		disk_scale = 0
-		for i, volume in enumerate(volumes):
-			volume_scale = max([sample.records[volume] - min_used[volume]
-			                    for sample in trace.monitor_disk
-			                    if volume in sample.records])
-			# Does not take length of volume name into account, but fixed offset
-			# works okay in practice.
-			draw_legend_box(ctx, '%s (max: %u MiB)' % (volume, volume_scale / 1024 / 1024),
-			                VOLUME_COLORS[i % len(VOLUME_COLORS)],
-			                off_x + i * 250, curr_y+20, leg_s)
-			disk_scale += volume_scale
+    # render disk space usage
+    #
+    # Draws the amount of disk space used on each volume relative to the
+    # lowest recorded amount. The graphs for each volume are stacked above
+    # each other so that total disk usage is visible.
+    if trace.monitor_disk:
+        ctx.set_font_size(LEGEND_FONT_SIZE)
+        # Determine set of volumes for which we have
+        # information and the minimal amount of used disk
+        # space for each. Currently samples are allowed to
+        # not have a values for all volumes; drawing could be
+        # made more efficient if that wasn't the case.
+        volumes = set()
+        min_used = {}
+        for sample in trace.monitor_disk:
+            for volume, used in sample.records.items():
+                volumes.add(volume)
+                if volume not in min_used or min_used[volume] > used:
+                    min_used[volume] = used
+        volumes = sorted(list(volumes))
+        disk_scale = 0
+        for i, volume in enumerate(volumes):
+            volume_scale = max([sample.records[volume] - min_used[volume]
+                                for sample in trace.monitor_disk
+                                if volume in sample.records])
+            # Does not take length of volume name into account, but fixed offset
+            # works okay in practice.
+            draw_legend_box(ctx, '%s (max: %u MiB)' % (volume, volume_scale / 1024 / 1024),
+                            VOLUME_COLORS[i % len(VOLUME_COLORS)],
+                            off_x + i * 250, curr_y+20, leg_s)
+            disk_scale += volume_scale
 
-		# render used amount of disk space
-		chart_rect = (off_x, curr_y+30, w, bar_h)
-		if clip_visible (clip, chart_rect):
-			draw_box_ticks (ctx, chart_rect, sec_w)
-			draw_annotations (ctx, proc_tree, trace.times, chart_rect)
-			for i in range(len(volumes), 0, -1):
-				draw_chart (ctx, VOLUME_COLORS[(i - 1) % len(VOLUME_COLORS)], True, chart_rect, \
-				            [(sample.time,
-				              # Sum up used space of all volumes including the current one
-				              # so that the graphs appear as stacked on top of each other.
-				              reduce(lambda x,y: x+y,
-				                     [sample.records[volume] - min_used[volume]
-				                      for volume in volumes[0:i]
-				                      if volume in sample.records],
-				                     0))
-				             for sample in trace.monitor_disk], \
-				            proc_tree, [0, disk_scale])
+        # render used amount of disk space
+        chart_rect = (off_x, curr_y+30, w, bar_h)
+        if clip_visible (clip, chart_rect):
+            draw_box_ticks (ctx, chart_rect, sec_w)
+            draw_annotations (ctx, proc_tree, trace.times, chart_rect)
+            for i in range(len(volumes), 0, -1):
+                draw_chart (ctx, VOLUME_COLORS[(i - 1) % len(VOLUME_COLORS)], True, chart_rect, \
+                            [(sample.time,
+                              # Sum up used space of all volumes including the current one
+                              # so that the graphs appear as stacked on top of each other.
+                              functools.reduce(lambda x,y: x+y,
+                                     [sample.records[volume] - min_used[volume]
+                                      for volume in volumes[0:i]
+                                      if volume in sample.records],
+                                     0))
+                             for sample in trace.monitor_disk], \
+                            proc_tree, [0, disk_scale])
 
-		curr_y = curr_y + 30 + bar_h
+        curr_y = curr_y + 30 + bar_h
 
-	# render mem usage
-	chart_rect = (off_x, curr_y+30, w, meminfo_bar_h)
-	mem_stats = trace.mem_stats
-	if mem_stats and clip_visible (clip, chart_rect):
-		mem_scale = max(sample.buffers for sample in mem_stats)
-		draw_legend_box(ctx, "Mem cached (scale: %u MiB)" % (float(mem_scale) / 1024), MEM_CACHED_COLOR, off_x, curr_y+20, leg_s)
-		draw_legend_box(ctx, "Used", MEM_USED_COLOR, off_x + 240, curr_y+20, leg_s)
-		draw_legend_box(ctx, "Buffers", MEM_BUFFERS_COLOR, off_x + 360, curr_y+20, leg_s)
-		draw_legend_line(ctx, "Swap (scale: %u MiB)" % max([(sample.swap)/1024 for sample in mem_stats]), \
-				 MEM_SWAP_COLOR, off_x + 480, curr_y+20, leg_s)
-		draw_box_ticks(ctx, chart_rect, sec_w)
-		draw_annotations(ctx, proc_tree, trace.times, chart_rect)
-		draw_chart(ctx, MEM_BUFFERS_COLOR, True, chart_rect, \
-			   [(sample.time, sample.buffers) for sample in trace.mem_stats], \
-			   proc_tree, [0, mem_scale])
-		draw_chart(ctx, MEM_USED_COLOR, True, chart_rect, \
-			   [(sample.time, sample.used) for sample in mem_stats], \
-			   proc_tree, [0, mem_scale])
-		draw_chart(ctx, MEM_CACHED_COLOR, True, chart_rect, \
-			   [(sample.time, sample.cached) for sample in mem_stats], \
-			   proc_tree, [0, mem_scale])
-		draw_chart(ctx, MEM_SWAP_COLOR, False, chart_rect, \
-			   [(sample.time, float(sample.swap)) for sample in mem_stats], \
-			   proc_tree, None)
+    # render mem usage
+    chart_rect = (off_x, curr_y+30, w, meminfo_bar_h)
+    mem_stats = trace.mem_stats
+    if mem_stats and clip_visible (clip, chart_rect):
+        mem_scale = max(sample.buffers for sample in mem_stats)
+        draw_legend_box(ctx, "Mem cached (scale: %u MiB)" % (float(mem_scale) / 1024), MEM_CACHED_COLOR, off_x, curr_y+20, leg_s)
+        draw_legend_box(ctx, "Used", MEM_USED_COLOR, off_x + 240, curr_y+20, leg_s)
+        draw_legend_box(ctx, "Buffers", MEM_BUFFERS_COLOR, off_x + 360, curr_y+20, leg_s)
+        draw_legend_line(ctx, "Swap (scale: %u MiB)" % max([(sample.swap)/1024 for sample in mem_stats]), \
+                 MEM_SWAP_COLOR, off_x + 480, curr_y+20, leg_s)
+        draw_box_ticks(ctx, chart_rect, sec_w)
+        draw_annotations(ctx, proc_tree, trace.times, chart_rect)
+        draw_chart(ctx, MEM_BUFFERS_COLOR, True, chart_rect, \
+               [(sample.time, sample.buffers) for sample in trace.mem_stats], \
+               proc_tree, [0, mem_scale])
+        draw_chart(ctx, MEM_USED_COLOR, True, chart_rect, \
+               [(sample.time, sample.used) for sample in mem_stats], \
+               proc_tree, [0, mem_scale])
+        draw_chart(ctx, MEM_CACHED_COLOR, True, chart_rect, \
+               [(sample.time, sample.cached) for sample in mem_stats], \
+               proc_tree, [0, mem_scale])
+        draw_chart(ctx, MEM_SWAP_COLOR, False, chart_rect, \
+               [(sample.time, float(sample.swap)) for sample in mem_stats], \
+               proc_tree, None)
 
-		curr_y = curr_y + meminfo_bar_h
+        curr_y = curr_y + meminfo_bar_h
 
-	return curr_y
+    return curr_y
 
 def render_processes_chart(ctx, options, trace, curr_y, w, h, sec_w):
-        chart_rect = [off_x, curr_y+header_h, w, h - 2 * off_y - header_h - leg_s + proc_h]
+    chart_rect = [off_x, curr_y+header_h, w, h - curr_y - 1 * off_y - header_h  ]
 
-	draw_legend_box (ctx, "Configure", \
-			 TASK_COLOR_CONFIGURE, off_x  , curr_y + 45, leg_s)
-	draw_legend_box (ctx, "Compile", \
-			 TASK_COLOR_COMPILE, off_x+120, curr_y + 45, leg_s)
-	draw_legend_box (ctx, "Install", \
-			 TASK_COLOR_INSTALL, off_x+240, curr_y + 45, leg_s)
-	draw_legend_box (ctx, "Populate Sysroot", \
-			 TASK_COLOR_SYSROOT, off_x+360, curr_y + 45, leg_s)
-	draw_legend_box (ctx, "Package", \
-			 TASK_COLOR_PACKAGE, off_x+480, curr_y + 45, leg_s)
-	draw_legend_box (ctx, "Package Write",
-			 TASK_COLOR_PACKAGE_WRITE, off_x+600, curr_y + 45, leg_s)
+    draw_legend_box (ctx, "Configure", \
+             TASK_COLOR_CONFIGURE, off_x  , curr_y + 45, leg_s)
+    draw_legend_box (ctx, "Compile", \
+             TASK_COLOR_COMPILE, off_x+120, curr_y + 45, leg_s)
+    draw_legend_box (ctx, "Install", \
+             TASK_COLOR_INSTALL, off_x+240, curr_y + 45, leg_s)
+    draw_legend_box (ctx, "Populate Sysroot", \
+             TASK_COLOR_SYSROOT, off_x+360, curr_y + 45, leg_s)
+    draw_legend_box (ctx, "Package", \
+             TASK_COLOR_PACKAGE, off_x+480, curr_y + 45, leg_s)
+    draw_legend_box (ctx, "Package Write", \
+             TASK_COLOR_PACKAGE_WRITE, off_x+600, curr_y + 45, leg_s)
 
-	ctx.set_font_size(PROC_TEXT_FONT_SIZE)
+    ctx.set_font_size(PROC_TEXT_FONT_SIZE)
 
-	draw_box_ticks(ctx, chart_rect, sec_w)
-	draw_sec_labels(ctx, options, chart_rect, sec_w, 30)
+    draw_box_ticks(ctx, chart_rect, sec_w)
+    draw_sec_labels(ctx, options, chart_rect, sec_w, 30)
 
-	y = curr_y+header_h
+    y = curr_y+header_h
 
-        offset = trace.min or min(trace.start.keys())
-        for s in sorted(trace.start.keys()):
-            for val in sorted(trace.start[s]):
-                if not options.app_options.show_all and \
-                   trace.processes[val][1] - s < options.app_options.mintime:
-                    continue
-                task = val.split(":")[1]
-                #print val
-                #print trace.processes[val][1]
-                #print s
-                x = chart_rect[0] + (s - offset) * sec_w
-                w = ((trace.processes[val][1] - s) * sec_w)
+    offset = trace.min or min(trace.start.keys())
+    for start in sorted(trace.start.keys()):
+        for process in sorted(trace.start[start]):
+            if not options.app_options.show_all and \
+                    trace.processes[process][1] - start < options.app_options.mintime:
+                continue
+            task = process.split(":")[1]
 
-                #print "proc at %s %s %s %s" % (x, y, w, proc_h)
-                col = None
-                if task == "do_compile":
-                    col = TASK_COLOR_COMPILE
-                elif task == "do_configure":
-                    col = TASK_COLOR_CONFIGURE
-                elif task == "do_install":
-                    col = TASK_COLOR_INSTALL
-                elif task == "do_populate_sysroot":
-                    col = TASK_COLOR_SYSROOT
-                elif task == "do_package":
-                    col = TASK_COLOR_PACKAGE
-                elif task == "do_package_write_rpm" or \
+            #print(process)
+            #print(trace.processes[process][1])
+            #print(s)
+
+            x = chart_rect[0] + (start - offset) * sec_w
+            w = ((trace.processes[process][1] - start) * sec_w)
+
+            #print("proc at %s %s %s %s" % (x, y, w, proc_h))
+            col = None
+            if task == "do_compile":
+                col = TASK_COLOR_COMPILE
+            elif task == "do_configure":
+                col = TASK_COLOR_CONFIGURE
+            elif task == "do_install":
+                col = TASK_COLOR_INSTALL
+            elif task == "do_populate_sysroot":
+                col = TASK_COLOR_SYSROOT
+            elif task == "do_package":
+                col = TASK_COLOR_PACKAGE
+            elif task == "do_package_write_rpm" or \
                      task == "do_package_write_deb" or \
                      task == "do_package_write_ipk":
-                    col = TASK_COLOR_PACKAGE_WRITE
-                else:
-                    col = WHITE
+                col = TASK_COLOR_PACKAGE_WRITE
+            else:
+                col = WHITE
 
-                if col:
-                    draw_fill_rect(ctx, col, (x, y, w, proc_h))
-                draw_rect(ctx, PROC_BORDER_COLOR, (x, y, w, proc_h))
+            if col:
+                draw_fill_rect(ctx, col, (x, y, w, proc_h))
+            draw_rect(ctx, PROC_BORDER_COLOR, (x, y, w, proc_h))
 
-                draw_label_in_box(ctx, PROC_TEXT_COLOR, val, x, y + proc_h - 4, w, proc_h)
-                y = y + proc_h
+            draw_label_in_box(ctx, PROC_TEXT_COLOR, process, x, y + proc_h - 4, w, proc_h)
+            y = y + proc_h
 
-	return curr_y
+    return curr_y
 
 #
 # Render the chart.
 #
 def render(ctx, options, xscale, trace):
-	(w, h) = extents (options, xscale, trace)
-	global OPTIONS
-	OPTIONS = options.app_options
+    (w, h) = extents (options, xscale, trace)
+    global OPTIONS
+    OPTIONS = options.app_options
 
-	# x, y, w, h
-	clip = ctx.clip_extents()
+    # x, y, w, h
+    clip = ctx.clip_extents()
 
-	sec_w = int (xscale * sec_w_base)
-	ctx.set_line_width(1.0)
-	ctx.select_font_face(FONT_NAME)
-	draw_fill_rect(ctx, WHITE, (0, 0, max(w, MIN_IMG_W), h))
-	w -= 2*off_x
-	curr_y = off_y;
+    sec_w = int (xscale * sec_w_base)
+    ctx.set_line_width(1.0)
+    ctx.select_font_face(FONT_NAME)
+    draw_fill_rect(ctx, WHITE, (0, 0, max(w, MIN_IMG_W), h))
+    w -= 2*off_x
+    curr_y = off_y;
 
-	if options.charts:
-		curr_y = render_charts (ctx, options, clip, trace, curr_y, w, h, sec_w)
+    if options.charts:
+        curr_y = render_charts (ctx, options, clip, trace, curr_y, w, h, sec_w)
 
-	curr_y = render_processes_chart (ctx, options, trace, curr_y, w, h, sec_w)
+    curr_y = render_processes_chart (ctx, options, trace, curr_y, w, h, sec_w)
 
-	return
+    return
 
-	proc_tree = options.proc_tree (trace)
+    proc_tree = options.proc_tree (trace)
 
-	# draw the title and headers
-	if proc_tree.idle:
-		duration = proc_tree.idle
-	else:
-		duration = proc_tree.duration
+    # draw the title and headers
+    if proc_tree.idle:
+        duration = proc_tree.idle
+    else:
+        duration = proc_tree.duration
 
-	if not options.kernel_only:
-		curr_y = draw_header (ctx, trace.headers, duration)
-	else:
-		curr_y = off_y;
+    if not options.kernel_only:
+        curr_y = draw_header (ctx, trace.headers, duration)
+    else:
+        curr_y = off_y;
 
-	# draw process boxes
-	proc_height = h
-	if proc_tree.taskstats and options.cumulative:
-		proc_height -= CUML_HEIGHT
+    # draw process boxes
+    proc_height = h
+    if proc_tree.taskstats and options.cumulative:
+        proc_height -= CUML_HEIGHT
 
-	draw_process_bar_chart(ctx, clip, options, proc_tree, trace.times,
-			       curr_y, w, proc_height, sec_w)
+    draw_process_bar_chart(ctx, clip, options, proc_tree, trace.times,
+                   curr_y, w, proc_height, sec_w)
 
-	curr_y = proc_height
-	ctx.set_font_size(SIG_FONT_SIZE)
-	draw_text(ctx, SIGNATURE, SIG_COLOR, off_x + 5, proc_height - 8)
+    curr_y = proc_height
+    ctx.set_font_size(SIG_FONT_SIZE)
+    draw_text(ctx, SIGNATURE, SIG_COLOR, off_x + 5, proc_height - 8)
 
-	# draw a cumulative CPU-time-per-process graph
-	if proc_tree.taskstats and options.cumulative:
-		cuml_rect = (off_x, curr_y + off_y, w, CUML_HEIGHT/2 - off_y * 2)
-		if clip_visible (clip, cuml_rect):
-			draw_cuml_graph(ctx, proc_tree, cuml_rect, duration, sec_w, STAT_TYPE_CPU)
+    # draw a cumulative CPU-time-per-process graph
+    if proc_tree.taskstats and options.cumulative:
+        cuml_rect = (off_x, curr_y + off_y, w, CUML_HEIGHT/2 - off_y * 2)
+        if clip_visible (clip, cuml_rect):
+            draw_cuml_graph(ctx, proc_tree, cuml_rect, duration, sec_w, STAT_TYPE_CPU)
 
-	# draw a cumulative I/O-time-per-process graph
-	if proc_tree.taskstats and options.cumulative:
-		cuml_rect = (off_x, curr_y + off_y * 100, w, CUML_HEIGHT/2 - off_y * 2)
-		if clip_visible (clip, cuml_rect):
-			draw_cuml_graph(ctx, proc_tree, cuml_rect, duration, sec_w, STAT_TYPE_IO)
+    # draw a cumulative I/O-time-per-process graph
+    if proc_tree.taskstats and options.cumulative:
+        cuml_rect = (off_x, curr_y + off_y * 100, w, CUML_HEIGHT/2 - off_y * 2)
+        if clip_visible (clip, cuml_rect):
+            draw_cuml_graph(ctx, proc_tree, cuml_rect, duration, sec_w, STAT_TYPE_IO)
 
 def draw_process_bar_chart(ctx, clip, options, proc_tree, times, curr_y, w, h, sec_w):
-	header_size = 0
-	if not options.kernel_only:
-		draw_legend_box (ctx, "Running (%cpu)",
-				 PROC_COLOR_R, off_x    , curr_y + 45, leg_s)
-		draw_legend_box (ctx, "Unint.sleep (I/O)",
-				 PROC_COLOR_D, off_x+120, curr_y + 45, leg_s)
-		draw_legend_box (ctx, "Sleeping",
-				 PROC_COLOR_S, off_x+240, curr_y + 45, leg_s)
-		draw_legend_box (ctx, "Zombie",
-				 PROC_COLOR_Z, off_x+360, curr_y + 45, leg_s)
-		header_size = 45
+    header_size = 0
+    if not options.kernel_only:
+        draw_legend_box (ctx, "Running (%cpu)",
+                 PROC_COLOR_R, off_x    , curr_y + 45, leg_s)
+        draw_legend_box (ctx, "Unint.sleep (I/O)",
+                 PROC_COLOR_D, off_x+120, curr_y + 45, leg_s)
+        draw_legend_box (ctx, "Sleeping",
+                 PROC_COLOR_S, off_x+240, curr_y + 45, leg_s)
+        draw_legend_box (ctx, "Zombie",
+                 PROC_COLOR_Z, off_x+360, curr_y + 45, leg_s)
+        header_size = 45
 
-	chart_rect = [off_x, curr_y + header_size + 15,
-		      w, h - 2 * off_y - (curr_y + header_size + 15) + proc_h]
-	ctx.set_font_size (PROC_TEXT_FONT_SIZE)
+    chart_rect = [off_x, curr_y + header_size + 15,
+              w, h - 2 * off_y - (curr_y + header_size + 15) + proc_h]
+    ctx.set_font_size (PROC_TEXT_FONT_SIZE)
 
-	draw_box_ticks (ctx, chart_rect, sec_w)
-	if sec_w > 100:
-		nsec = 1
-	else:
-		nsec = 5
-	draw_sec_labels (ctx, options, chart_rect, sec_w, nsec)
-	draw_annotations (ctx, proc_tree, times, chart_rect)
+    draw_box_ticks (ctx, chart_rect, sec_w)
+    if sec_w > 100:
+        nsec = 1
+    else:
+        nsec = 5
+    draw_sec_labels (ctx, options, chart_rect, sec_w, nsec)
+    draw_annotations (ctx, proc_tree, times, chart_rect)
 
-	y = curr_y + 60
-	for root in proc_tree.process_tree:
-		draw_processes_recursively(ctx, root, proc_tree, y, proc_h, chart_rect, clip)
-		y = y + proc_h * proc_tree.num_nodes([root])
+    y = curr_y + 60
+    for root in proc_tree.process_tree:
+        draw_processes_recursively(ctx, root, proc_tree, y, proc_h, chart_rect, clip)
+        y = y + proc_h * proc_tree.num_nodes([root])
 
 
 def draw_header (ctx, headers, duration):
@@ -678,291 +685,291 @@
     return header_y
 
 def draw_processes_recursively(ctx, proc, proc_tree, y, proc_h, rect, clip) :
-	x = rect[0] +  ((proc.start_time - proc_tree.start_time) * rect[2] / proc_tree.duration)
-	w = ((proc.duration) * rect[2] / proc_tree.duration)
+    x = rect[0] +  ((proc.start_time - proc_tree.start_time) * rect[2] / proc_tree.duration)
+    w = ((proc.duration) * rect[2] / proc_tree.duration)
 
-	draw_process_activity_colors(ctx, proc, proc_tree, x, y, w, proc_h, rect, clip)
-	draw_rect(ctx, PROC_BORDER_COLOR, (x, y, w, proc_h))
-	ipid = int(proc.pid)
-	if not OPTIONS.show_all:
-		cmdString = proc.cmd
-	else:
-		cmdString = ''
-	if (OPTIONS.show_pid or OPTIONS.show_all) and ipid is not 0:
-		cmdString = cmdString + " [" + str(ipid // 1000) + "]"
-	if OPTIONS.show_all:
-		if proc.args:
-			cmdString = cmdString + " '" + "' '".join(proc.args) + "'"
-		else:
-			cmdString = cmdString + " " + proc.exe
+    draw_process_activity_colors(ctx, proc, proc_tree, x, y, w, proc_h, rect, clip)
+    draw_rect(ctx, PROC_BORDER_COLOR, (x, y, w, proc_h))
+    ipid = int(proc.pid)
+    if not OPTIONS.show_all:
+        cmdString = proc.cmd
+    else:
+        cmdString = ''
+    if (OPTIONS.show_pid or OPTIONS.show_all) and ipid is not 0:
+        cmdString = cmdString + " [" + str(ipid // 1000) + "]"
+    if OPTIONS.show_all:
+        if proc.args:
+            cmdString = cmdString + " '" + "' '".join(proc.args) + "'"
+        else:
+            cmdString = cmdString + " " + proc.exe
 
-	draw_label_in_box(ctx, PROC_TEXT_COLOR, cmdString, x, y + proc_h - 4, w, rect[0] + rect[2])
+    draw_label_in_box(ctx, PROC_TEXT_COLOR, cmdString, x, y + proc_h - 4, w, rect[0] + rect[2])
 
-	next_y = y + proc_h
-	for child in proc.child_list:
-		if next_y > clip[1] + clip[3]:
-			break
-		child_x, child_y = draw_processes_recursively(ctx, child, proc_tree, next_y, proc_h, rect, clip)
-		draw_process_connecting_lines(ctx, x, y, child_x, child_y, proc_h)
-		next_y = next_y + proc_h * proc_tree.num_nodes([child])
+    next_y = y + proc_h
+    for child in proc.child_list:
+        if next_y > clip[1] + clip[3]:
+            break
+        child_x, child_y = draw_processes_recursively(ctx, child, proc_tree, next_y, proc_h, rect, clip)
+        draw_process_connecting_lines(ctx, x, y, child_x, child_y, proc_h)
+        next_y = next_y + proc_h * proc_tree.num_nodes([child])
 
-	return x, y
+    return x, y
 
 
 def draw_process_activity_colors(ctx, proc, proc_tree, x, y, w, proc_h, rect, clip):
 
-	if y > clip[1] + clip[3] or y + proc_h + 2 < clip[1]:
-		return
+    if y > clip[1] + clip[3] or y + proc_h + 2 < clip[1]:
+        return
 
-	draw_fill_rect(ctx, PROC_COLOR_S, (x, y, w, proc_h))
+    draw_fill_rect(ctx, PROC_COLOR_S, (x, y, w, proc_h))
 
-	last_tx = -1
-	for sample in proc.samples :
-		tx = rect[0] + round(((sample.time - proc_tree.start_time) * rect[2] / proc_tree.duration))
+    last_tx = -1
+    for sample in proc.samples :
+        tx = rect[0] + round(((sample.time - proc_tree.start_time) * rect[2] / proc_tree.duration))
 
-		# samples are sorted chronologically
-		if tx < clip[0]:
-			continue
-		if tx > clip[0] + clip[2]:
-			break
+        # samples are sorted chronologically
+        if tx < clip[0]:
+            continue
+        if tx > clip[0] + clip[2]:
+            break
 
-		tw = round(proc_tree.sample_period * rect[2] / float(proc_tree.duration))
-		if last_tx != -1 and abs(last_tx - tx) <= tw:
-			tw -= last_tx - tx
-			tx = last_tx
-		tw = max (tw, 1) # nice to see at least something
+        tw = round(proc_tree.sample_period * rect[2] / float(proc_tree.duration))
+        if last_tx != -1 and abs(last_tx - tx) <= tw:
+            tw -= last_tx - tx
+            tx = last_tx
+        tw = max (tw, 1) # nice to see at least something
 
-		last_tx = tx + tw
-		state = get_proc_state( sample.state )
+        last_tx = tx + tw
+        state = get_proc_state( sample.state )
 
-		color = STATE_COLORS[state]
-		if state == STATE_RUNNING:
-			alpha = min (sample.cpu_sample.user + sample.cpu_sample.sys, 1.0)
-			color = tuple(list(PROC_COLOR_R[0:3]) + [alpha])
-#			print "render time %d [ tx %d tw %d ], sample state %s color %s alpha %g" % (sample.time, tx, tw, state, color, alpha)
-		elif state == STATE_SLEEPING:
-			continue
+        color = STATE_COLORS[state]
+        if state == STATE_RUNNING:
+            alpha = min (sample.cpu_sample.user + sample.cpu_sample.sys, 1.0)
+            color = tuple(list(PROC_COLOR_R[0:3]) + [alpha])
+#            print "render time %d [ tx %d tw %d ], sample state %s color %s alpha %g" % (sample.time, tx, tw, state, color, alpha)
+        elif state == STATE_SLEEPING:
+            continue
 
-		draw_fill_rect(ctx, color, (tx, y, tw, proc_h))
+        draw_fill_rect(ctx, color, (tx, y, tw, proc_h))
 
 def draw_process_connecting_lines(ctx, px, py, x, y, proc_h):
-	ctx.set_source_rgba(*DEP_COLOR)
-	ctx.set_dash([2, 2])
-	if abs(px - x) < 3:
-		dep_off_x = 3
-		dep_off_y = proc_h / 4
-		ctx.move_to(x, y + proc_h / 2)
-		ctx.line_to(px - dep_off_x, y + proc_h / 2)
-		ctx.line_to(px - dep_off_x, py - dep_off_y)
-		ctx.line_to(px, py - dep_off_y)
-	else:
-		ctx.move_to(x, y + proc_h / 2)
-		ctx.line_to(px, y + proc_h / 2)
-		ctx.line_to(px, py)
-	ctx.stroke()
-	ctx.set_dash([])
+    ctx.set_source_rgba(*DEP_COLOR)
+    ctx.set_dash([2, 2])
+    if abs(px - x) < 3:
+        dep_off_x = 3
+        dep_off_y = proc_h / 4
+        ctx.move_to(x, y + proc_h / 2)
+        ctx.line_to(px - dep_off_x, y + proc_h / 2)
+        ctx.line_to(px - dep_off_x, py - dep_off_y)
+        ctx.line_to(px, py - dep_off_y)
+    else:
+        ctx.move_to(x, y + proc_h / 2)
+        ctx.line_to(px, y + proc_h / 2)
+        ctx.line_to(px, py)
+    ctx.stroke()
+    ctx.set_dash([])
 
 # elide the bootchart collector - it is quite distorting
 def elide_bootchart(proc):
-	return proc.cmd == 'bootchartd' or proc.cmd == 'bootchart-colle'
+    return proc.cmd == 'bootchartd' or proc.cmd == 'bootchart-colle'
 
 class CumlSample:
-	def __init__(self, proc):
-		self.cmd = proc.cmd
-		self.samples = []
-		self.merge_samples (proc)
-		self.color = None
+    def __init__(self, proc):
+        self.cmd = proc.cmd
+        self.samples = []
+        self.merge_samples (proc)
+        self.color = None
 
-	def merge_samples(self, proc):
-		self.samples.extend (proc.samples)
-		self.samples.sort (key = lambda p: p.time)
+    def merge_samples(self, proc):
+        self.samples.extend (proc.samples)
+        self.samples.sort (key = lambda p: p.time)
 
-	def next(self):
-		global palette_idx
-		palette_idx += HSV_STEP
-		return palette_idx
+    def next(self):
+        global palette_idx
+        palette_idx += HSV_STEP
+        return palette_idx
 
-	def get_color(self):
-		if self.color is None:
-			i = self.next() % HSV_MAX_MOD
-			h = 0.0
-			if i is not 0:
-				h = (1.0 * i) / HSV_MAX_MOD
-			s = 0.5
-			v = 1.0
-			c = colorsys.hsv_to_rgb (h, s, v)
-			self.color = (c[0], c[1], c[2], 1.0)
-		return self.color
+    def get_color(self):
+        if self.color is None:
+            i = self.next() % HSV_MAX_MOD
+            h = 0.0
+            if i is not 0:
+                h = (1.0 * i) / HSV_MAX_MOD
+            s = 0.5
+            v = 1.0
+            c = colorsys.hsv_to_rgb (h, s, v)
+            self.color = (c[0], c[1], c[2], 1.0)
+        return self.color
 
 
 def draw_cuml_graph(ctx, proc_tree, chart_bounds, duration, sec_w, stat_type):
-	global palette_idx
-	palette_idx = 0
+    global palette_idx
+    palette_idx = 0
 
-	time_hash = {}
-	total_time = 0.0
-	m_proc_list = {}
+    time_hash = {}
+    total_time = 0.0
+    m_proc_list = {}
 
-	if stat_type is STAT_TYPE_CPU:
-		sample_value = 'cpu'
-	else:
-		sample_value = 'io'
-	for proc in proc_tree.process_list:
-		if elide_bootchart(proc):
-			continue
+    if stat_type is STAT_TYPE_CPU:
+        sample_value = 'cpu'
+    else:
+        sample_value = 'io'
+    for proc in proc_tree.process_list:
+        if elide_bootchart(proc):
+            continue
 
-		for sample in proc.samples:
-			total_time += getattr(sample.cpu_sample, sample_value)
-			if not sample.time in time_hash:
-				time_hash[sample.time] = 1
+        for sample in proc.samples:
+            total_time += getattr(sample.cpu_sample, sample_value)
+            if not sample.time in time_hash:
+                time_hash[sample.time] = 1
 
-		# merge pids with the same cmd
-		if not proc.cmd in m_proc_list:
-			m_proc_list[proc.cmd] = CumlSample (proc)
-			continue
-		s = m_proc_list[proc.cmd]
-		s.merge_samples (proc)
+        # merge pids with the same cmd
+        if not proc.cmd in m_proc_list:
+            m_proc_list[proc.cmd] = CumlSample (proc)
+            continue
+        s = m_proc_list[proc.cmd]
+        s.merge_samples (proc)
 
-	# all the sample times
-	times = sorted(time_hash)
-	if len (times) < 2:
-		print("degenerate boot chart")
-		return
+    # all the sample times
+    times = sorted(time_hash)
+    if len (times) < 2:
+        print("degenerate boot chart")
+        return
 
-	pix_per_ns = chart_bounds[3] / total_time
-#	print "total time: %g pix-per-ns %g" % (total_time, pix_per_ns)
+    pix_per_ns = chart_bounds[3] / total_time
+#    print "total time: %g pix-per-ns %g" % (total_time, pix_per_ns)
 
-	# FIXME: we have duplicates in the process list too [!] - why !?
+    # FIXME: we have duplicates in the process list too [!] - why !?
 
-	# Render bottom up, left to right
-	below = {}
-	for time in times:
-		below[time] = chart_bounds[1] + chart_bounds[3]
+    # Render bottom up, left to right
+    below = {}
+    for time in times:
+        below[time] = chart_bounds[1] + chart_bounds[3]
 
-	# same colors each time we render
-	random.seed (0)
+    # same colors each time we render
+    random.seed (0)
 
-	ctx.set_line_width(1)
+    ctx.set_line_width(1)
 
-	legends = []
-	labels = []
+    legends = []
+    labels = []
 
-	# render each pid in order
-	for cs in m_proc_list.values():
-		row = {}
-		cuml = 0.0
+    # render each pid in order
+    for cs in m_proc_list.values():
+        row = {}
+        cuml = 0.0
 
-		# print "pid : %s -> %g samples %d" % (proc.cmd, cuml, len (cs.samples))
-		for sample in cs.samples:
-			cuml += getattr(sample.cpu_sample, sample_value)
-			row[sample.time] = cuml
+        # print "pid : %s -> %g samples %d" % (proc.cmd, cuml, len (cs.samples))
+        for sample in cs.samples:
+            cuml += getattr(sample.cpu_sample, sample_value)
+            row[sample.time] = cuml
 
-		process_total_time = cuml
+        process_total_time = cuml
 
-		# hide really tiny processes
-		if cuml * pix_per_ns <= 2:
-			continue
+        # hide really tiny processes
+        if cuml * pix_per_ns <= 2:
+            continue
 
-		last_time = times[0]
-		y = last_below = below[last_time]
-		last_cuml = cuml = 0.0
+        last_time = times[0]
+        y = last_below = below[last_time]
+        last_cuml = cuml = 0.0
 
-		ctx.set_source_rgba(*cs.get_color())
-		for time in times:
-			render_seg = False
+        ctx.set_source_rgba(*cs.get_color())
+        for time in times:
+            render_seg = False
 
-			# did the underlying trend increase ?
-			if below[time] != last_below:
-				last_below = below[last_time]
-				last_cuml = cuml
-				render_seg = True
+            # did the underlying trend increase ?
+            if below[time] != last_below:
+                last_below = below[last_time]
+                last_cuml = cuml
+                render_seg = True
 
-			# did we move up a pixel increase ?
-			if time in row:
-				nc = round (row[time] * pix_per_ns)
-				if nc != cuml:
-					last_cuml = cuml
-					cuml = nc
-					render_seg = True
+            # did we move up a pixel increase ?
+            if time in row:
+                nc = round (row[time] * pix_per_ns)
+                if nc != cuml:
+                    last_cuml = cuml
+                    cuml = nc
+                    render_seg = True
 
-#			if last_cuml > cuml:
-#				assert fail ... - un-sorted process samples
+#            if last_cuml > cuml:
+#                assert fail ... - un-sorted process samples
 
-			# draw the trailing rectangle from the last time to
-			# before now, at the height of the last segment.
-			if render_seg:
-				w = math.ceil ((time - last_time) * chart_bounds[2] / proc_tree.duration) + 1
-				x = chart_bounds[0] + round((last_time - proc_tree.start_time) * chart_bounds[2] / proc_tree.duration)
-				ctx.rectangle (x, below[last_time] - last_cuml, w, last_cuml)
-				ctx.fill()
-#				ctx.stroke()
-				last_time = time
-				y = below [time] - cuml
+            # draw the trailing rectangle from the last time to
+            # before now, at the height of the last segment.
+            if render_seg:
+                w = math.ceil ((time - last_time) * chart_bounds[2] / proc_tree.duration) + 1
+                x = chart_bounds[0] + round((last_time - proc_tree.start_time) * chart_bounds[2] / proc_tree.duration)
+                ctx.rectangle (x, below[last_time] - last_cuml, w, last_cuml)
+                ctx.fill()
+#                ctx.stroke()
+                last_time = time
+                y = below [time] - cuml
 
-			row[time] = y
+            row[time] = y
 
-		# render the last segment
-		x = chart_bounds[0] + round((last_time - proc_tree.start_time) * chart_bounds[2] / proc_tree.duration)
-		y = below[last_time] - cuml
-		ctx.rectangle (x, y, chart_bounds[2] - x, cuml)
-		ctx.fill()
-#		ctx.stroke()
+        # render the last segment
+        x = chart_bounds[0] + round((last_time - proc_tree.start_time) * chart_bounds[2] / proc_tree.duration)
+        y = below[last_time] - cuml
+        ctx.rectangle (x, y, chart_bounds[2] - x, cuml)
+        ctx.fill()
+#        ctx.stroke()
 
-		# render legend if it will fit
-		if cuml > 8:
-			label = cs.cmd
-			extnts = ctx.text_extents(label)
-			label_w = extnts[2]
-			label_h = extnts[3]
-#			print "Text extents %g by %g" % (label_w, label_h)
-			labels.append((label,
-				       chart_bounds[0] + chart_bounds[2] - label_w - off_x * 2,
-				       y + (cuml + label_h) / 2))
-			if cs in legends:
-				print("ARGH - duplicate process in list !")
+        # render legend if it will fit
+        if cuml > 8:
+            label = cs.cmd
+            extnts = ctx.text_extents(label)
+            label_w = extnts[2]
+            label_h = extnts[3]
+#            print "Text extents %g by %g" % (label_w, label_h)
+            labels.append((label,
+                       chart_bounds[0] + chart_bounds[2] - label_w - off_x * 2,
+                       y + (cuml + label_h) / 2))
+            if cs in legends:
+                print("ARGH - duplicate process in list !")
 
-		legends.append ((cs, process_total_time))
+        legends.append ((cs, process_total_time))
 
-		below = row
+        below = row
 
-	# render grid-lines over the top
-	draw_box_ticks(ctx, chart_bounds, sec_w)
+    # render grid-lines over the top
+    draw_box_ticks(ctx, chart_bounds, sec_w)
 
-	# render labels
-	for l in labels:
-		draw_text(ctx, l[0], TEXT_COLOR, l[1], l[2])
+    # render labels
+    for l in labels:
+        draw_text(ctx, l[0], TEXT_COLOR, l[1], l[2])
 
-	# Render legends
-	font_height = 20
-	label_width = 300
-	LEGENDS_PER_COL = 15
-	LEGENDS_TOTAL = 45
-	ctx.set_font_size (TITLE_FONT_SIZE)
-	dur_secs = duration / 100
-	cpu_secs = total_time / 1000000000
+    # Render legends
+    font_height = 20
+    label_width = 300
+    LEGENDS_PER_COL = 15
+    LEGENDS_TOTAL = 45
+    ctx.set_font_size (TITLE_FONT_SIZE)
+    dur_secs = duration / 100
+    cpu_secs = total_time / 1000000000
 
-	# misleading - with multiple CPUs ...
-#	idle = ((dur_secs - cpu_secs) / dur_secs) * 100.0
-	if stat_type is STAT_TYPE_CPU:
-		label = "Cumulative CPU usage, by process; total CPU: " \
-			" %.5g(s) time: %.3g(s)" % (cpu_secs, dur_secs)
-	else:
-		label = "Cumulative I/O usage, by process; total I/O: " \
-			" %.5g(s) time: %.3g(s)" % (cpu_secs, dur_secs)
+    # misleading - with multiple CPUs ...
+#    idle = ((dur_secs - cpu_secs) / dur_secs) * 100.0
+    if stat_type is STAT_TYPE_CPU:
+        label = "Cumulative CPU usage, by process; total CPU: " \
+            " %.5g(s) time: %.3g(s)" % (cpu_secs, dur_secs)
+    else:
+        label = "Cumulative I/O usage, by process; total I/O: " \
+            " %.5g(s) time: %.3g(s)" % (cpu_secs, dur_secs)
 
-	draw_text(ctx, label, TEXT_COLOR, chart_bounds[0] + off_x,
-		  chart_bounds[1] + font_height)
+    draw_text(ctx, label, TEXT_COLOR, chart_bounds[0] + off_x,
+          chart_bounds[1] + font_height)
 
-	i = 0
-	legends = sorted(legends, key=itemgetter(1), reverse=True)
-	ctx.set_font_size(TEXT_FONT_SIZE)
-	for t in legends:
-		cs = t[0]
-		time = t[1]
-		x = chart_bounds[0] + off_x + int (i/LEGENDS_PER_COL) * label_width
-		y = chart_bounds[1] + font_height * ((i % LEGENDS_PER_COL) + 2)
-		str = "%s - %.0f(ms) (%2.2f%%)" % (cs.cmd, time/1000000, (time/total_time) * 100.0)
-		draw_legend_box(ctx, str, cs.color, x, y, leg_s)
-		i = i + 1
-		if i >= LEGENDS_TOTAL:
-			break
+    i = 0
+    legends = sorted(legends, key=itemgetter(1), reverse=True)
+    ctx.set_font_size(TEXT_FONT_SIZE)
+    for t in legends:
+        cs = t[0]
+        time = t[1]
+        x = chart_bounds[0] + off_x + int (i/LEGENDS_PER_COL) * label_width
+        y = chart_bounds[1] + font_height * ((i % LEGENDS_PER_COL) + 2)
+        str = "%s - %.0f(ms) (%2.2f%%)" % (cs.cmd, time/1000000, (time/total_time) * 100.0)
+        draw_legend_box(ctx, str, cs.color, x, y, leg_s)
+        i = i + 1
+        if i >= LEGENDS_TOTAL:
+            break