From: Jiri Olsa <jolsa@redhat.com>
To: kan.liang@intel.com
Cc: acme@kernel.org, peterz@infradead.org, mingo@redhat.com,
linux-kernel@vger.kernel.org, jolsa@kernel.org,
namhyung@kernel.org, adrian.hunter@intel.com,
lukasz.odzioba@intel.com, ak@linux.intel.com
Subject: Re: [PATCH RFC V2 00/10] perf top optimization
Date: Mon, 18 Sep 2017 10:57:08 +0200 [thread overview]
Message-ID: <20170918085708.GC17203@krava> (raw)
In-Reply-To: <1505096603-215017-1-git-send-email-kan.liang@intel.com>
On Sun, Sep 10, 2017 at 07:23:13PM -0700, kan.liang@intel.com wrote:
> From: Kan Liang <kan.liang@intel.com>
>
> The patch series intends to fix the severe performance issue in
> Knights Landing/Mill, when monitoring in heavy load system.
> perf top costs a few minutes to show the result, which is
> unacceptable.
> With the patch series applied, the latency will reduces to
> several seconds.
>
> machine__synthesize_threads and perf_top__mmap_read costs most of
> the perf top time (> 99%).
looks like this patchset adds locking into code paths
used by other single threaded tools and that might
be bad for them as noted by Andi in here:
https://marc.info/?l=linux-kernel&m=149031672928989&w=2
he proposed solution and it was changed&posted by Arnaldo in here:
https://marc.info/?l=linux-kernel&m=149132267410294&w=2
but looks like it never got merged
could you please add this or similar code before you add the
locking code/overhead in?
thanks,
jirka
next prev parent reply other threads:[~2017-09-18 8:57 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-11 2:23 [PATCH RFC V2 00/10] perf top optimization kan.liang
2017-09-11 2:23 ` [PATCH RFC V2 01/10] perf tools: hashtable for machine threads kan.liang
2017-09-13 13:29 ` Arnaldo Carvalho de Melo
2017-09-22 16:42 ` [tip:perf/core] perf machine: Use " tip-bot for Kan Liang
2017-09-11 2:23 ` [PATCH RFC V2 02/10] perf tools: using scandir to replace readdir kan.liang
2017-09-13 15:19 ` Arnaldo Carvalho de Melo
2017-09-11 2:23 ` [PATCH RFC V2 03/10] petf tools: using comm_str to replace comm in hist_entry kan.liang
2017-09-13 15:21 ` Arnaldo Carvalho de Melo
2017-09-18 8:38 ` Jiri Olsa
2017-09-11 2:23 ` [PATCH RFC V2 04/10] petf tools: introduce a new function to set namespaces id kan.liang
2017-09-11 2:23 ` [PATCH RFC V2 05/10] perf tools: lock to protect thread list kan.liang
2017-09-18 8:50 ` Jiri Olsa
2017-09-18 16:18 ` Liang, Kan
2017-09-11 2:23 ` [PATCH RFC V2 06/10] perf tools: lock to protect comm_str rb tree kan.liang
2017-09-11 2:23 ` [PATCH RFC V2 07/10] perf tools: change machine comm_exec type to atomic kan.liang
2017-09-13 15:24 ` Arnaldo Carvalho de Melo
2017-09-15 20:05 ` Liang, Kan
2017-09-18 11:30 ` Jiri Olsa
2017-09-11 2:23 ` [PATCH RFC V2 08/10] perf top: implement multithreading for perf_event__synthesize_threads kan.liang
2017-09-18 11:24 ` Jiri Olsa
2017-09-11 2:23 ` [PATCH RFC V2 09/10] perf top: add option to set the number of thread for event synthesize kan.liang
2017-09-11 2:23 ` [PATCH RFC V2 10/10] perf top: switch back to overwrite mode kan.liang
2017-09-13 15:25 ` [PATCH RFC V2 00/10] perf top optimization Arnaldo Carvalho de Melo
2017-09-13 15:29 ` Liang, Kan
2017-09-13 15:38 ` Arnaldo Carvalho de Melo
2017-09-14 21:19 ` Arnaldo Carvalho de Melo
2017-09-15 15:11 ` Liang, Kan
2017-09-15 17:26 ` Arnaldo Carvalho de Melo
2017-09-15 17:29 ` Liang, Kan
2017-09-15 18:24 ` Arnaldo Carvalho de Melo
2017-09-15 18:26 ` Liang, Kan
2017-09-18 8:57 ` Jiri Olsa [this message]
2017-09-18 13:01 ` Arnaldo Carvalho de Melo
2017-09-18 16:21 ` Liang, Kan
2017-09-19 8:19 ` Jiri Olsa
2017-09-19 12:39 ` Liang, Kan
2017-09-19 14:24 ` Arnaldo Carvalho de Melo
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