lkml.org 
[lkml]   [2010]   [Jun]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    SubjectRe: [PATCH 3/5] perf: New PERF_EVENT_STATE_PAUSED event state
    From
    Date
    On Thu, 2010-06-10 at 05:49 +0200, Frederic Weisbecker wrote:
    > This brings a new PERF_EVENT_STATE_PAUSED state. It means the events
    > is enabled but we don't want it to run, it must be in the same state
    > than after a pmu->stop() call. So the event has been reserved and
    > allocated and it is ready to start after a pmu->start() call.
    >
    > It is deemed for hardware events when we want them to be reserved on
    > the cpu and ready to be started anytime. This is going to be useful
    > for the new context exclusion that will follow.
    >
    > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
    > Cc: Ingo Molnar <mingo@elte.hu>
    > Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
    > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
    > Cc: Paul Mackerras <paulus@samba.org>
    > Cc: Stephane Eranian <eranian@google.com>
    > Cc: Cyrill Gorcunov <gorcunov@gmail.com>
    > Cc: Zhang Yanmin <yanmin_zhang@linux.intel.com>
    > Cc: Steven Rostedt <rostedt@goodmis.org>
    > ---
    > arch/x86/kernel/cpu/perf_event.c | 6 ++++--
    > include/linux/perf_event.h | 3 ++-
    > kernel/perf_event.c | 7 ++++---
    > 3 files changed, 10 insertions(+), 6 deletions(-)
    >
    > diff --git a/arch/x86/kernel/cpu/perf_event.c b/arch/x86/kernel/cpu/perf_event.c
    > index f2da20f..9b0e52f 100644
    > --- a/arch/x86/kernel/cpu/perf_event.c
    > +++ b/arch/x86/kernel/cpu/perf_event.c
    > @@ -839,7 +839,8 @@ void hw_perf_enable(void)
    > match_prev_assignment(hwc, cpuc, i))
    > continue;
    >
    > - x86_pmu_stop(event);
    > + if (event->state != PERF_EVENT_STATE_PAUSED)
    > + x86_pmu_stop(event);
    > }
    >
    > for (i = 0; i < cpuc->n_events; i++) {
    > @@ -851,7 +852,8 @@ void hw_perf_enable(void)
    > else if (i < n_running)
    > continue;
    >
    > - x86_pmu_start(event);
    > + if (event->state != PERF_EVENT_STATE_PAUSED)
    > + x86_pmu_start(event);
    > }
    > cpuc->n_added = 0;
    > perf_events_lapic_init();

    Shouldn't that latter be == PAUSED?

    Also, you'll have to audit all struct pmu implementations that
    stop/disable or disable/disable is good.

    Also, I'd rather keep the whole event->state knowledge in the generic
    code.


    \
     
     \ /
      Last update: 2010-06-10 12:57    [W:0.025 / U:1.080 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site