Messages in this thread | | | Subject | Re: [RFC][PATCH v2 11/11] perf top: demo of how to use the sysfs interface | From | Lin Ming <> | Date | Thu, 20 May 2010 09:17:29 +0800 |
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On Thu, 2010-05-20 at 02:18 +0800, Corey Ashford wrote: > > On 5/18/2010 6:49 PM, Lin Ming wrote: > > Just a temporary patch to show how to use the pmu sysfs interface... > > > > Signed-off-by: Lin Ming <ming.m.lin@intel.com> > > --- > > tools/perf/builtin-top.c | 13 +++++++++++++ > > 1 files changed, 13 insertions(+), 0 deletions(-) > > > > diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c > > index adc179d..eaa9405 100644 > > --- a/tools/perf/builtin-top.c > > +++ b/tools/perf/builtin-top.c > > @@ -1206,6 +1206,7 @@ static void start_counter(int i, int counter) > > struct perf_event_attr *attr; > > int cpu; > > int thread_index; > > + int sys_fd; > > > > cpu = profile_cpu; > > if (target_tid == -1 && profile_cpu == -1) > > @@ -1226,9 +1227,21 @@ static void start_counter(int i, int counter) > > > > for (thread_index = 0; thread_index < thread_num; thread_index++) { > > try_again: > > + /* > > + * This is just an ugly demo of how to use the sysfs interface. > > + * You can also parse the <event-name> and open sys file as, > > + * sys_fd = open("/sys/devices/system/cpu/events/<event-name>/event_source/id", O_RDONLY); > > + */ > > In this above case, does this sys_fd also specify the event I am going to open, in addition to its event source? I'd assume not since event_source is a symlink to /sys/devices/system/cpu/event_source (right?)
Right, this sys_fd only specifies the event source.
> How do I specify the exact event id via the sysfs interface?
/sys/devices/system/cpu/events/<event-name>/id
But in this patch series, the event id sysfs interface is not used yet.
Thanks, Lin Ming
> > Thanks, > > - Corey >
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