Messages in this thread | | | Date | Tue, 08 Oct 2013 15:03:58 +0900 | From | Masami Hiramatsu <> | Subject | Re: [PATCH v2 0/3] Perf support to SDT markers |
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Hi,
(2013/10/07 15:46), Hemant Kumar wrote: > This patchset helps in probing dtrace style markers(SDT) present in user space > applications through perf. Notes/markes are placed at important places by the > developers. They have a negligible overhead when not enabled. We can enable > them and probe at these places and find some important information like the > arguments' values, etc.
Thank you for updating! By the way, could you rebase this series to the latest -tip kernel next time? It is more convenient for us to test & merge it.
[...] > - Now use perf to list the markers in the app: > # perf probe --markers -x ./user_app > > %user_app:foo_start > %user_app:fun_start
Here, what I got.
$ ./perf probe --markers -x /lib64/librt.so %librt:lll_futex_wake
OK, it lists up markers.
$ ./perf probe --markers -x ./perf SDT markers not present! Error : Failed to find SDT markers!(-1)
OK, this shows an error, INHO, it'd better show which binary doesn't have markers.
$ ./perf probe --markers Failed to open (null) Error : Failed to find SDT markers!(-1)
Hmm, it's a bit odd error. It should check if there is an elf binary is specified.
$ ./perf probe --markers /lib64/librt.so %librt:lll_futex_wake
It seems to work without -x. However, that is only when the path is started with /. And also the usage is not described by --help.
$ ./perf probe --markers ./perf Semantic error :File always requires line number or lazy pattern. Error: Parse Error. (-22)
So, to avoid confusion, --markers should abort without -x(--exec) option.
> - And then use perf probe to add a probe point : > > # perf probe -x ./user_app -a '%user_app:foo_start'
And also, without -x, -a also exits with an odd error message.
$ ./perf probe -a %libm:slowexp_p6 Failed to open (null) Error: Failed to add events. (-1)
I'll review each patch soon.
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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