pseq: Add presence caching to Services
Add caching of hardware presence data to the Services class in the
phosphor-power-sequencer application. Obtaining hardware presence from
D-Bus is a slow operation. During pgood fault isolation, multiple rails
may need the same hardware presence information. Cache this information
to improve performance.
Provide a method to clear the cached data since it is only valid for a
short period of time. For example, power supplies are hot-pluggable, so
their presence may change while a system is powered on.
Tested:
* BMCServices
* createPMBus()
* Verify correct sysfs path passed to PMBus constructor
* isPresent()
* Test where hardware is present
* Test where value is not cached
* Verify value is cached after data obtained from D-Bus
* Test where value is cached
* Test where hardware is not present
* Test where value is not cached
* Verify value is cached after data obtained from D-Bus
* Test where value is cached
* Test where D-Bus method call fails with an expected exception
* Verify false is stored in cache
* Verify false is returned
* Test where D-Bus method call fails with an unexpected exception
* Verify nothing is cached
* Verify exception is re-thrown
* clearCache()
* Verify clears all cached data
* MockServices
* Verify all methods can be called from an automated test
* Run existing automated tests
Change-Id: I3e92be3ded1ed333acbedc970409176cabe98c09
Signed-off-by: Shawn McCarney <shawnmm@us.ibm.com>
diff --git a/phosphor-power-sequencer/src/services.cpp b/phosphor-power-sequencer/src/services.cpp
index 80ad464..9c9ace7 100644
--- a/phosphor-power-sequencer/src/services.cpp
+++ b/phosphor-power-sequencer/src/services.cpp
@@ -61,24 +61,36 @@
// Initially assume hardware is not present
bool present{false};
- // Get presence from D-Bus interface/property
- try
+ // Try to find cached presence value
+ auto it = presenceCache.find(inventoryPath);
+ if (it != presenceCache.end())
{
- util::getProperty(INVENTORY_IFACE, PRESENT_PROP, inventoryPath,
- INVENTORY_MGR_IFACE, bus, present);
+ present = it->second;
}
- catch (const sdbusplus::exception_t& e)
+ else
{
- // If exception type is expected and indicates hardware not present
- if (isExpectedException(e))
+ // Get presence from D-Bus interface/property
+ try
{
- present = false;
+ util::getProperty(INVENTORY_IFACE, PRESENT_PROP, inventoryPath,
+ INVENTORY_MGR_IFACE, bus, present);
}
- else
+ catch (const sdbusplus::exception_t& e)
{
- // Re-throw unexpected exception
- throw;
+ // If exception type is expected and indicates hardware not present
+ if (isExpectedException(e))
+ {
+ present = false;
+ }
+ else
+ {
+ // Re-throw unexpected exception
+ throw;
+ }
}
+
+ // Cache presence value
+ presenceCache[inventoryPath] = present;
}
return present;