Hi folks! As mentioned by this discussion https://lkml.org/lkml/2016/1/7/661, perf does not record the build id for modules, which are hit on the way down the callstack. Sadly that issue is not completely fixed by the cmd argument --buildid-all. In my case, I have my own kernel module starting a kernel thread. It does some stuff, and calls schedule from time to time. If I start perf like this
perf record -e sched:sched_stat_sleep -e sched:sched_switch -a -g -o
perf.data.raw -p <pid> -- sleep 10
, it records the callstacks for those three events.
Afterwards I want to do some post processing to generate a cold graph:
perf inject -v -s -i perf.data.raw -o perf.data
That step fails ('failed to write feature 2') due to the lack of a
build-id for my module, which isn't included in perf.data.raw.
Can anyone confirm that this is a bug?
Does anyone have a workaround for it?
Thanks in advance!
Cheers,
Alex
P.S.: Pls put me in CC, because I'm not subscribed to the mailinglist.
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