Messages in this thread | | | From | Eiichi Tsukata <> | Subject | Re: [PATCH v2] cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink | Date | Thu, 26 May 2022 00:02:00 +0000 |
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Hi Steven
> On May 26, 2022, at 1:02, Steven Rostedt <rostedt@goodmis.org> wrote: > > On Mon, 23 May 2022 23:53:32 +0000 > Eiichi Tsukata <eiichi.tsukata@nutanix.com> wrote: > >> @@ -91,16 +95,17 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns) >> val = guest_halt_poll_ns; >> >> dev->poll_limit_ns = val; >> + trace_guest_halt_poll_ns_grow(smp_processor_id(), val, old); > > Why are you passing in smp_processor_id()? > >> } else if (block_ns > guest_halt_poll_ns && >> guest_halt_poll_allow_shrink) { >> unsigned int shrink = guest_halt_poll_shrink; >> >> - val = dev->poll_limit_ns; >> if (shrink == 0) >> val = 0; >> else >> val /= shrink; >> dev->poll_limit_ns = val; >> + trace_guest_halt_poll_ns_shrink(smp_processor_id(), val, old); >> } >> } >> >> diff --git a/include/trace/events/power.h b/include/trace/events/power.h >> index af5018aa9517..db065af9c3c0 100644 >> --- a/include/trace/events/power.h >> +++ b/include/trace/events/power.h >> @@ -500,6 +500,39 @@ DEFINE_EVENT(dev_pm_qos_request, dev_pm_qos_remove_request, >> >> TP_ARGS(name, type, new_value) >> ); >> + >> +TRACE_EVENT(guest_halt_poll_ns, >> + >> + TP_PROTO(bool grow, unsigned int cpu_id, >> + unsigned int new, unsigned int old), >> + >> + TP_ARGS(grow, cpu_id, new, old), >> + >> + TP_STRUCT__entry( >> + __field(bool, grow) >> + __field(unsigned int, cpu_id) >> + __field(unsigned int, new) >> + __field(unsigned int, old) >> + ), >> + >> + TP_fast_assign( >> + __entry->grow = grow; >> + __entry->cpu_id = cpu_id; > > You are wasting space to save the cpu_id, as the trace event already knows > what CPU it occurred on. > > # echo 1 > events/sched/enable > # cat trace > # TASK-PID CPU# ||||| TIMESTAMP FUNCTION > # | | | ||||| | | > systemd-1 [004] ..... 15.872715: ftrace_boot_snapshot: ** Boot snapshot taken ** > systemd-1 [001] ..... 22.555418: initcall_start: func=fuse_len_args+0x0/0x30 [fuse] > systemd-1 [001] ..... 22.555425: initcall_finish: func=fuse_len_args+0x0/0x30 [fuse] ret=0 > modprobe-643 [006] ..... 26.737355: initcall_start: func=wmidev_evaluate_method+0x46/0x100 [wmi] > modprobe-643 [006] ..... 26.742491: initcall_finish: func=wmidev_evaluate_method+0x46/0x100 [wmi] ret=0 > > -- Steve
Thanks for your suggestion. I added cpu_id as there is a similar precedent “trace_cpu_idle” but I think we can remove cpu_id. Will fix it in v3.
Eiichi | |