Re: [PATCH tracing/kprobes 0/7] tracing/kprobes: kprobe-based eventtracer update and perf support
From: Frederic Weisbecker
Date: Sun Sep 13 2009 - 23:00:00 EST
On Fri, Sep 11, 2009 at 12:03:30PM -0400, Masami Hiramatsu wrote:
>
Frederic Weisbecker wrote:
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> May be another step in the todo-list that would be nice: define the format
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> for a type. Like it's done from ftrace events.
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>
Thanks!
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>
BTW, I'm not sure what the type means. Each event already has its own
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event ID and event_call. Could you tell me which part of ftrace I should
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refer to ?
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Actually I meant the format for a field.
Say you define filename=arg1, it would be nice to have
print "%s", filename
in the format file.
Hmm, now that I think about it, we can't dereference an array...for now :-)
>
> I guess we should choose between the low level, very granular
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> but uninviting method "kprobe + record + trace" and also an all
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> in one quick approach.
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>
>
> And that could be chosen from perf kprobe:
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>
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> Low level:
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>
>
> perf kprobe --define-only [-p|-r] [probe_name] -a1 [arg1] -a2 [arg2] \
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> --format="%s %...."
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>
>
> perf record -e kprobes:probe_name
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> perf trace
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>
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> Quick:
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>
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> perf kprobe -p probe_name -a1 ..... cmdline| -a
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>
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> And after the profiled task is finished, it could launch perf trace
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> by itself (or wait for a Ctrl + C if -a/wide profiling)
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>
Another thought: expand record subcommand.
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>
perf record -E "p|r:probe_name,place,arg1,arg2..."
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perf trace
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>
And kprobe accept multiple definitions
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>
perf kprobe -E "p|r:probe_name,place,arg1,arg2..." -E ...
Well, perf record could also support multiple definitions
too...
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