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

From: Daniel Wagner
Date: Tue Aug 30 2016 - 07:39:54 EST

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 :)