Re: [drm/i915/gt] 8c3b1ba0e7: perf-sanity-tests.Parse_event_definition_strings.fail
From: Jiri Olsa
Date: Thu Feb 25 2021 - 08:35:49 EST
On Thu, Feb 25, 2021 at 04:06:23PM +0800, Jin, Yao wrote:
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Hi Chris, Arnaldo, Jiri,
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We observe the parsing error for "software/xxx/" on some platforms.
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For example,
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# perf stat -e software/r1a/ -a -- sleep 1
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event syntax error: 'software/r1a/'
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\___ parser error
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Run 'perf list' for a list of valid events
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Usage: perf stat [<options>] [<command>]
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-e, --event <event> event selector. use 'perf list' to list available events
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And perf test is failed too.
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# perf test 6 -vv
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...
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running test 4 'software/r1a/'failed to parse event 'software/r1a/', err 1, str 'parser error'
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event syntax error: 'software/r1a/'
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\___ parser error
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running test 4 'software/r0x1a/'failed to parse event 'software/r0x1a/', err 1, str 'parser error'
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event syntax error: 'software/r0x1a/'
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\___ parser error
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...
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The issue should be the conflict between event "i915/software-gt-awake-time/" and pmu "software".
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# perf list | grep i915/software
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i915/software-gt-awake-time/ [Kernel PMU event]
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Perf supports the event format as "prefix-xxx-suffix", so the "software"
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string in "software-gt-awake-time" is added to perf_pmu_events_list as
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PMU_EVENT_SYMBOL_PREFIX. When parsing the string such as "software/xxx/",
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it’s parsed as PMU_EVENT_SYMBOL_PREFIX for "software", then it would error
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out in next processing.
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So the easy way is to rename "software-gt-awake-time" to "gt-awake-time",
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right? Otherwise we have to hardcode something in perf tool.
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What do you think of this issue and the solution?
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BTW, as the robot reported, it's related to the commit 8c3b1ba0e7ea
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("drm/i915/gt: Track the overall awake/busy time").
yes, I think you're right.. I'll try to reproduce and check on this
I'm still not clear why is that parsing fail if those 2 events are
distinguished by - and / ... but yep, we are asking for trouble in
here ;-)
I think we could either prioritaze one or add extra check when we
add prefix-xxx-suffix events and do not add ones that have conflict..
that seems like best solution to me now
thanks,
jirka