Re: Profiling sleep times?

[Arun Sharma <asharma@fb.com>]

On 10/6/11 6:30 PM, Peter Zijlstra wrote:

>
> But the idea of the __perf_count() thing:
> [..]
> 	TP_perf_assign(
> 		__perf_count(delay);
> 	),
>
> 	TP_printk("comm=%s pid=%d delay=%Lu [ns]",
> 			__entry->comm, __entry->pid,
> 			(unsigned long long)__entry->delay)
> );
>
>
> is that the counter is incremented with the delay, so the event should
> get weighted right.
>
> So having to get the delay out of the raw tracepoint data shouldn't be
> needed.

How does this work for dynamic tracepoints? Or tracepoints with multiple 
dimensions where the user might want to query each dimension separately?

Andrew: what do you think about generalizing my patch to accept a 
command line option(s) to specify which fields to use for the purpose of 
computing the histogram?

For static tracepoints, TP_perf_assign() could act as a hint on which 
field to default to.

  -Arun