Messages in this thread | | | Date | Wed, 26 Feb 2014 21:41:51 +0530 | From | Hemant Kumar <> | Subject | Re: [RFC PATCH v1 0/2] perf: Support for SDT markers |
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On 02/26/2014 03:12 PM, Masami Hiramatsu wrote: > (2014/02/26 18:03), Hemant Kumar wrote: >> On 02/26/2014 01:48 PM, Namhyung Kim wrote: >>> Hi Masami and Hemant, >>> >>> On Tue, 25 Feb 2014 21:27:07 +0530, Hemant Kumar wrote: >>>> On 02/25/2014 05:14 PM, Masami Hiramatsu wrote: >>>>> (2014/02/24 18:14), Hemant Kumar wrote: >>>>>> First, scan the binaries using : >>>>>> # perf list sdt --scan >>>>>> >>>>>> Creating a cache of SDT markers... >>>>>> perf sdt cache created! >>>>>> Use : "perf list sdt" >>>>>> to see the SDT markers >>>>> Hmm, in that case, I think you'd better introduce perf-sdt for scanning. >>>>> e.g. >>>>> >>>>> # perf sdt --scan app >>>> Hmm, this seems a better idea :) >>>> >>>>> then you can add app to sdt cache, without app, >>>>> >>>>> # perf sdt --scan >>>>> >>>>> will just scans all binaries on the PATH and the libraries which listed >>>>> by `ldconfig --print-caceh` >>> What should be done with the new perf sdt command? If it's only >>> intended to list the markers, I'd just suggest to add "perf list sdt" as >>> this patch did. > No, here what I said is, the "perf sdt" is only for managing SDT cache > as like as "perf buildid-cache". Thus, "perf sdt-cache" might be better.
Ah! ok.
> BTW, the SDT markers can be changed if the application is updated. > To ensure the correctness of SDT markers, we should store buildid in the > cache file and check it when listing and using them.
Yeah! That's why perf list sdt --scan is storing the buildid too in the cache file.
>> If we display the SDT markers along with the other events in perf list, >> then I think we can go with >> perf list sdt. I am not too sure though! :) >> >> For me, the main issue was that the markers are not events. They become >> events after >> we place them in the uprobe_events file just like functions. But we use >> `perf list` to >> display all the "events" available on a system. Isn't it? > As I said, if perf accepts -e "%app:sdt" option, showing SDT events as > fixed events does not matter, since it is transparent to users. :) > > Thank you, >
Alright. Got it! :)
-- Thanks Hemant Kumar
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