Re: [PATCH v4 0/3] *** Latency histograms - IRQSOFF,PREEMPTOFF ***

From: Masami Hiramatsu
Date: Tue Aug 30 2016 - 08:02:38 EST


2016-08-30 20:39 GMT+09:00 Daniel Wagner <daniel.wagner@xxxxxxxxxxxx>:
> Hi Binoy,
>
> On 08/30/2016 12:28 PM, Binoy Jayan wrote:
>>
>> Examples of triggers:
>> echo 'hist:key=latency.log2:val=hitcount:sort=latency' >
>> /sys/kernel/debug/tracing/events/latency/latency_preempt/trigger
>> echo 'hist:key=cpu,latency:val=hitcount:sort=latency if cpu==1' >
>> /sys/kernel/debug/tracing/events/latency/latency_preempt/trigger
>> echo 'hist:key=ltype,cpu:val=latency:sort=ltype,cpu if ltype==0' >
>> /sys/kernel/debug/tracing/events/latency/latency_preempt/trigger
>>
>> Histogram output:
>> cat /sys/kernel/debug/tracing/events/latency/latency_preempt/hist
>
>
> Could you also add couple of test cases to
> tools/testing/selftests/ftrace/test.d/trigger?
>
> Especially the sorting thing you mentioned in the other mail? Obviously
> first we need to figure out what is the expected behavior of it :)

Good idea! And also, for both patch, could you show the output examples?
It might help people to imagine what it provides.

Thank you,



--
Masami Hiramatsu