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

[Frederic Weisbecker <fweisbec@gmail.com>]

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@linaro.com>
> ---
>  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.