Messages in this thread | | | Subject | Re: [RFC][PATCH 3/9] perf: export registerred pmus via sysfs | From | Lin Ming <> | Date | Tue, 11 May 2010 17:40:45 +0800 |
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On Tue, 2010-05-11 at 17:12 +0800, Peter Zijlstra wrote: > On Tue, 2010-05-11 at 17:03 +0800, Lin Ming wrote: > > On Tue, 2010-05-11 at 16:50 +0800, Peter Zijlstra wrote: > > > On Tue, 2010-05-11 at 16:20 +0800, Lin Ming wrote: > > > > > > > How will this sysfs interface be used for userspace tool? > > > > > > > > /sys/devices/system/node/nodeN/node_events > > > > node_events/event_source_id > > > > > > > > node_events/local_misses/event_id > > > > /local_hits/event_id > > > > /remote_misses/event_id > > > > /remote_hits/event_id > > > > > > > > For example, to monitor node event local_misses on node 0, does it work > > > > as below? > > > > > > > > 1. perf top -e local_misses -n 0 (-n 0 means node 0) > > > > > > > > 2. read /sys/devices/system/node/node0/node_events/event_source_id to > > > > get the pmu_id > > > > > > > > 3. read /sys/devices/system/node/node0/node_events/local_misses/event_id > > > > to get the event_id > > > > > > > > 4. event_attr::pmu_id=pmu_id, event::config=event_id > > > > > > > > 5. other setting... > > > > > > > > 6. call syscall perf_event_open(....) > > > > > > No, you'll use event_source_id as perf_event_attr::type, use event_id as > > > perf_event_attr::config and then use a cpu-wide counter on a cpu > > > contained in node0. > > > > Is event_source_id a link to event_source class? > > No its an attribute of said class. > > > For example, 2 event sources on Nehalem > > /sys/class/event_sources/core_pmu > > /sys/class/event_sources/uncore_pmu > > > > Then, > > /sys/devices/system/node/nodeN/node_events/event_source_id is a link > > to /sys/class/event_sources/uncore_pmu. > > > /sys/devices/system/cpu/cpuN/cpu_hardware_events/event_source_id is a > > link to /sys/class/event_sources/core_pmu. > > The other way around, look in /sys/class/*/, they're all symlinks.
/sys/devices/system/cpu/cpu0/cpu_hw_events/* /sys/devices/system/cpu/cpu0/cpu_hw_cache_events/* /sys/devices/system/cpu/cpu0/cpu_raw_events/* .... .... /sys/devices/system/cpu/cpuN/cpu_hw_events/* /sys/devices/system/cpu/cpuN/cpu_hw_cache_events/* /sys/devices/system/cpu/cpuN/cpu_raw_events/*
Is /sys/class/event_sources/* looks like,
/sys/class/event_sources/cpu_hw_events0 -> /sys/devices/system/cpu/cpu0/cpu_hw_events ... /sys/class/event_sources/cpu_hw_eventsN -> /sys/devices/system/cpu/cpuN/cpu_hw_events
/sys/class/event_sources/cpu_hw_cache_events0 -> /sys/devices/system/cpu/cpu0/cpu_hw_events ... /sys/class/event_sources/cpu_hw_cache_eventsN -> /sys/devices/system/cpu/cpuN/cpu_hw_events
?
> > > And, the event_source_id > > #cat /sys/class/event_sources/core_pmu > > 0 > > > #cat /sys/class/event_sources/uncore_pmu > > 1 > > You can't cat a directory. You'd cat something > like: /sys/class/event_sources/core_pmu/event_source_id > > And they would contain PERF_TYPE_* like things. > > So for the current CPU PMUs we'd already create 3 event classes, > cpu_hw_events, cpu_hw_cache_events, cpu_raw_events, with resp. > event_source_id of 0, 3 and 4. > > The new PMUs will use a dynamic range that starts at PERF_TYPE_MAX.
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