Messages in this thread | | | Date | Tue, 20 Oct 2009 20:05:57 -0400 | From | Masami Hiramatsu <> | Subject | Re: [PATCH -tip tracing/kprobes 0/9] tracing/kprobes, perf: perf probe and kprobe-tracer bugfixes |
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Ingo Molnar wrote: > * Masami Hiramatsu <mhiramat@redhat.com> wrote: >> Masami Hiramatsu wrote: >>> Ingo Molnar wrote: >>>> For example you might want to probe the point within schedule that calls >>>> switch_mm() - this could be done via: >>>> >>>> perf probe schedule@switch_mm >>>> >>>> Or the point where 'next' gets assigned? Sure, you dont need to even >>>> open the editor, if you know the rough outline of the function you can >>>> probe it via: >>>> >>>> perf probe schedule@'next =' >>>> >>>> Note that i was able to specify both probes without having opened an >>>> editor - just based on the general knowledge of the scheduler. >>> >>> It may be useful for return probe too :-) >>> >>> perf probe schedule@return >> >> Hmm, IMHO, >> >>>> perf probe schedule@switch_mm >> >> might be confused as 'probe schedule() called from switch_mm()'. >> >> BTW, there might be several local/inline functions which have >> same name. >> I think we'd better provide a syntax for solving this issue. >> And current syntax uses @ for this purpose as below. >> >> perf probe localfunc@file >> >> Maybe, we still can use % for special matching, >> >> perf probe schedule%switch_mm >> >> These can be combined with each other, as below. >> >> perf probe schedule@kernel/sched.c%switch_mm >> >> Or, supporting lazy string pattern matching >> (reusing glob matching in ftrace?) >> >> perf probe schedule:'switch_mm(*);' >> >> Just my thought. > > I'm not attached to any particular form of syntax here (other than it > should be simple and obvious) - we can try and see how it works out.
OK, so I'll try to implement it and see how it works out:-)
-- Masami Hiramatsu
Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division
e-mail: mhiramat@redhat.com
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