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Groups > linux.kernel > #1387692
| From | Peter Zijlstra <peterz@infradead.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: LBR callchains from tracepoints |
| Date | 2016-04-26 18:40 +0200 |
| Message-ID | <rsebM-2ma-7@gated-at.bofh.it> (permalink) |
| References | <rrZZ8-7nE-21@gated-at.bofh.it> <rrZZ8-7nE-23@gated-at.bofh.it> <rrZZ8-7nE-25@gated-at.bofh.it> <rrZZ8-7nE-27@gated-at.bofh.it> <rrZZ8-7nE-19@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Mon, Apr 25, 2016 at 10:24:31PM -0300, Arnaldo Carvalho de Melo wrote: > Em Mon, Apr 25, 2016 at 10:03:58PM -0300, Arnaldo Carvalho de Melo escreveu: > > I now need to continue investigation why this doesn't seem to work from > > tracepoints... > > Bummer, the changeset (at the end of this message) hasn't any > explanation, is this really impossible? I.e. LBR callstacks from > tracepoints? Even if we set perf_event_attr.exclude_callchain_kernel? Could maybe be done, but its tricky to implement as the LBR is managed by the hardware PMU and tracepoints are a software PMU, so we need to then somehow frob with cross-pmu resources, in a very arch specific way. And programmability of the hardware PMU will then depend on events outside of it. All rather icky.
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LBR callchains from tracepoints Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-04-26 03:30 +0200
Re: LBR callchains from tracepoints Peter Zijlstra <peterz@infradead.org> - 2016-04-26 18:40 +0200
Re: LBR callchains from tracepoints Alexei Starovoitov <alexei.starovoitov@gmail.com> - 2016-04-26 19:30 +0200
Re: LBR callchains from tracepoints Arnaldo Carvalho de Melo <acme@kernel.org> - 2016-04-26 20:30 +0200
Re: LBR callchains from tracepoints Peter Zijlstra <peterz@infradead.org> - 2016-04-26 21:10 +0200
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