Messages in this thread Patch in this message | | | Date | Wed, 25 May 2022 12:02:48 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v2] cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink |
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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
> + __entry->new = new; > + __entry->old = old; > + ), > + > + TP_printk("cpu %u: halt_poll_ns %u (%s %u)", > + __entry->cpu_id, > + __entry->new, > + __entry->grow ? "grow" : "shrink", > + __entry->old) > +); > +
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