Messages in this thread | | | Subject | Re: [RFC][PATCH v2 06/11] perf: core, export pmus via sysfs | From | Lin Ming <> | Date | Wed, 19 May 2010 10:34:55 +0800 |
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On Wed, 2010-05-19 at 04:05 +0800, Greg KH wrote: > On Wed, May 19, 2010 at 01:46:42AM +0000, Lin Ming wrote: > > Now only exports cpu hardware events. > > > > For each PMU, there are 2 sysfs dirs: event_source and events. > > > > For example, > > /sys/devices/system/cpu/event_source/ > > /sys/devices/system/cpu/events/ > > > > $ tree /sys/devices/system/cpu/event_source/ > > /sys/devices/system/cpu/event_source/ > > `-- id > > > > $ tree /sys/devices/system/cpu/events/ > > /sys/devices/system/cpu/events/ > > |-- L1-dcache-load-misses > > | |-- event_source -> ../../event_source > > What is this symlink for? Is it needed as they all seem to point to the > same thing.
The symlink is used to find the "event_source" of the "event".
/sys/devices/system/cpu/event_source/
/sys/devices/system/cpu/events/ |-- L1-dcache-load-misses | |-- event_source -> ../../event_source
For above example, "event_source" is the cpu pmu and the "event" is L1-dcache-load-misses.
Yes, they point to the same thing, because all the events under /sys/devices/system/cpu/events/* is monitored by the same event source, ie, the cpu pmu(/sys/devices/system/cpu/event_source/).
> > Also, as you are trying to add new sysfs interfaces, please document > them in Documentation/ABI.
Will add the document.
> > And, do you have to use "raw" kobjects here? Any chance you can use a > struct device instead?
Let me think about this.
> > I'm still not really understanding what exactly you are trying to show > in the sysfs tree here anyway, perhaps the documentation update will > clear that up for me.
To support multiple pmus(or call them event source), I want to show all the pmus and events in the sysfs tree.
For cpu pmu, /sys/devices/system/cpu/event_source/* /sys/devices/system/cpu/events/*
For node pmu, /sys/devices/system/node/event_source/* /sys/devices/system/node/events/*
For mce, /sys/kernel/events/mce/*
and so on...the exact placement is not yet final.
Thanks, Lin Ming
> > thanks, > > greg k-h
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