Re: [PATCH V2] tracing, perf : add cpu hotplug trace events

From: Frederic Weisbecker
Date: Thu Jan 20 2011 - 11:11:19 EST


On Thu, Jan 20, 2011 at 09:25:54AM +0100, Vincent Guittot wrote:
> Please find below a new proposal for adding trace events for cpu hotplug.
> The goal is to measure the latency of each part (kernel, architecture)
> and also to trace the cpu hotplug activity with other power events. I
> have tested these traces events on an arm platform.
>
> Changes since previous version:
> -Use cpu_hotplug for trace name
> -Define traces for kernel core and arch parts only
> -Use DECLARE_EVENT_CLASS and DEFINE_EVENT
> -Use proper indentation
>
> Subject: [PATCH] cpu hotplug tracepoint
>
> this patch adds new events for cpu hotplug tracing
> * plug/unplug sequence
> * core and architecture latency measurements
>
> Signed-off-by: Vincent Guittot <vincent.guittot@xxxxxxxxxx>
> ---
> include/trace/events/cpu_hotplug.h | 117 ++++++++++++++++++++++++++++++++++++

Note we can't apply new tracepoints if they are not inserted in the code.

> +DEFINE_EVENT(cpu_hotplug, cpu_hotplug_arch_wait_die_start,
> +
> + TP_PROTO(unsigned int cpuid),
> +
> + TP_ARGS(cpuid)
> +);
> +
> +DEFINE_EVENT(cpu_hotplug, cpu_hotplug_arch_wait_die_end,
> +
> + TP_PROTO(unsigned int cpuid),
> +
> + TP_ARGS(cpuid)
> +);

What is wait die, compared to die for example?

We need those tracepoints to be applied to get that reviewable in practice.

Thanks.
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