lkml.org 
[lkml]   [2019]   [Nov]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v7] perf: Sharing PMU counters across compatible events
    On Fri, Nov 15, 2019 at 03:55:04PM -0800, Song Liu wrote:

    SNIP

    > add_event_to_ctx(event, ctx);
    > }
    > @@ -2745,21 +2998,26 @@ static void __perf_event_enable(struct perf_event *event,
    > {
    > struct perf_event *leader = event->group_leader;
    > struct perf_event_context *task_ctx;
    > + int was_active;
    > + int event_type;
    >
    > if (event->state >= PERF_EVENT_STATE_INACTIVE ||
    > event->state <= PERF_EVENT_STATE_ERROR)
    > return;
    >
    > + event_type = perf_event_can_share(event) ? EVENT_ALL : EVENT_TIME;
    > + was_active = ctx->is_active;
    > if (ctx->is_active)
    > - ctx_sched_out(ctx, cpuctx, EVENT_TIME);
    > + ctx_sched_out(ctx, cpuctx, event_type);

    you're scheduling everything out in here, so cpuctx->task_ctx
    will become NULL and trigger the check below

    I dont think you need to do it here, ctx_resched will do that
    for you later, this here is just to keep the time updated

    jirka

    >
    > perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
    > + perf_event_setup_dup(event, ctx);
    >
    > - if (!ctx->is_active)
    > + if (!was_active)
    > return;
    >
    > if (!event_filter_match(event)) {
    > - ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
    > + ctx_sched_in(ctx, cpuctx, event_type, current);
    > return;
    > }
    >
    > @@ -2767,8 +3025,8 @@ static void __perf_event_enable(struct perf_event *event,
    > * If the event is in a group and isn't the group leader,
    > * then don't put it on unless the group is on.
    > */
    > - if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
    > - ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
    > + if (leader != event && leader->state <= PERF_EVENT_STATE_INACTIVE) {
    > + ctx_sched_in(ctx, cpuctx, event_type, current);
    > return;
    > }
    >
    > @@ -2776,7 +3034,8 @@ static void __perf_event_enable(struct perf_event *event,
    > if (ctx->task)
    > WARN_ON_ONCE(task_ctx != ctx);
    >
    > - ctx_resched(cpuctx, task_ctx, get_event_type(event));
    > + /* if perf_event_can_share() resched EVENT_ALL */
    > + ctx_resched(cpuctx, task_ctx, get_event_type(event) | event_type);
    > }

    SNIP

    \
     
     \ /
      Last update: 2019-11-28 09:31    [W:2.475 / U:0.136 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site