Messages in this thread | | | Date | Tue, 29 Oct 2013 12:19:37 +0900 | From | Masami Hiramatsu <> | Subject | Re: Re: [PATCH v4 2/3] Support for perf to probe into SDT markers: |
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(2013/10/29 2:48), Pekka Enberg wrote: > On 10/28/13 7:31 PM, Srikar Dronamraju wrote: >>>> But what if a system has both 32 bit libc and 64 bit libc? >>>> Wont we could end up with 2 libc:setjmp? >>>> Should we give some more intelligence into perf to choose the 64 bit >>>> libc over 32 bit one? >>> You can just trace both of them by default, no? >>> >> There has to be a one to one association with the event name and its >> mapping. Every event name will finally map to a unique inode and an >> offset. >> >> One option would be for perf to look at these markers and have a >> different event name for similar markers in different executables. > > I think we are talking past each other here. > > Yes, I understand that you need an fully qualified name > for a SDT marker but there's absolutely no reason to force > feed that to the user of 'perf trace'. > > For the 32-bit and 64-bit libc case, why cannot 'perf list' > by default print out something like: > > $ perf list > > libc:setjmp [SDT marker group] > > and provide a '--fully-qualified' command line option that: > > $ perf list --fully-qualified > > libc:setjmp => libc32:setjmp, libc64:setjmp [SDT marker group] > libc32:setjmp => libc:setjmp@/lib/libc.so.6 [SDT marker] > libc64:setjmp => libc:setjmp@/lib64/libc.so.6 [SDT marker] > > and then teach 'perf trace' to deal with SDT marker groups > where you trace two events, not one?
Ah, that's a good idea. :) And it also is needed for another probe event because sometimes inlined functions have multiple instances. I'd like to fold them as one event group.
Thank you! -- Masami HIRAMATSU IT Management Research Dept. Linux Technology Center Hitachi, Ltd., Yokohama Research Laboratory E-mail: masami.hiramatsu.pt@hitachi.com
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