From: Andi Kleen <ak@linux.intel.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>,
Jiri Olsa <jolsa@redhat.com>,
linux-kernel@vger.kernel.org, Namhyung Kim <namhyung@kernel.org>,
linux-perf-users@vger.kernel.org
Subject: Re: [PATCH 11/16] perf intel-pt: Add support for synthesizing callchains for regular events
Date: Sun, 19 Apr 2020 20:04:57 -0700 [thread overview]
Message-ID: <20200420030457.GA608746@tassilo.jf.intel.com> (raw)
In-Reply-To: <20200417213704.GB21512@kernel.org>
> Andi? My concern is that if this is the optimal solution for a good
> subset of the machines out there, then we need to make it easy to use,
> even transparent, if possible and safe to take that path.
I'm not sure it's that great in the general case. A PT call graph
would need a full PT recording from start to end.
The problem with full PT recording is that it doesn't really work for a
lot of workloads, because for anything doing enough computation the CPU
just generates too much data and you end up with a lot of gaps in the
trace when the perf record flushing cannot keep up.
Also even if it worked you might end up with far too much data that
will take a long time to process.
So I suspect it wouldn't work often enough to be generally useful.
For the leader sample case we just want to use some non PT method
to get the call graph.
-Andi
next prev parent reply other threads:[~2020-04-20 3:04 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-01 10:15 [PATCH 00/16] perf intel-pt: Sampling improvements Adrian Hunter
2020-04-01 10:15 ` [PATCH 01/16] perf auxtrace: Add ->evsel_is_auxtrace() callback Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:15 ` [PATCH 02/16] perf intel-pt: Implement " Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 03/16] perf intel-bts: " Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 04/16] perf arm-spe: " Adrian Hunter
2020-04-02 3:03 ` Leo Yan
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 05/16] perf cs-etm: " Adrian Hunter
2020-04-01 17:11 ` Mathieu Poirier
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 06/16] perf s390-cpumsf: " Adrian Hunter
2020-04-01 14:10 ` Thomas Richter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 07/16] perf auxtrace: For reporting purposes, un-group AUX area event Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 08/16] perf auxtrace: Add an option to synthesize callchains for regular events Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 09/16] perf thread-stack: Add thread_stack__sample_late() Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 10/16] perf tools: Add support for synthesized sample type Adrian Hunter
2020-04-16 14:54 ` Arnaldo Carvalho de Melo
2020-04-16 14:57 ` Arnaldo Carvalho de Melo
2020-04-16 15:01 ` Arnaldo Carvalho de Melo
2020-04-22 12:17 ` [tip: perf/core] perf evsel: Be consistent when looking which evsel PERF_SAMPLE_ bits are set tip-bot2 for Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] perf evsel: Add support for synthesized sample type tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 11/16] perf intel-pt: Add support for synthesizing callchains for regular events Adrian Hunter
2020-04-16 15:14 ` Arnaldo Carvalho de Melo
2020-04-17 13:50 ` Adrian Hunter
2020-04-17 21:37 ` Arnaldo Carvalho de Melo
2020-04-20 3:04 ` Andi Kleen [this message]
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 12/16] perf tools: Move and globalize perf_evsel__find_pmu() and perf_evsel__is_aux_event() Adrian Hunter
2020-04-18 11:50 ` Arnaldo Carvalho de Melo
2020-04-18 12:04 ` Arnaldo Carvalho de Melo
2020-04-22 12:17 ` [tip: perf/core] perf evsel: " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 13/16] perf tools: Move leader-sampling configuration Adrian Hunter
2020-04-16 15:29 ` Arnaldo Carvalho de Melo
2020-04-22 12:17 ` [tip: perf/core] perf evlist: " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 14/16] perf tools: Rearrange perf_evsel__config_leader_sampling() Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] perf evsel: " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 15/16] perf tools: Allow multiple read formats Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] perf evlist: " tip-bot2 for Adrian Hunter
2020-04-01 10:16 ` [PATCH 16/16] perf tools: Add support for leader-sampling with AUX area events Adrian Hunter
2020-04-22 12:17 ` [tip: perf/core] " tip-bot2 for Adrian Hunter
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