From: Ingo Molnar <mingo@kernel.org>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: linux-kernel@vger.kernel.org, Andi Kleen <ak@linux.intel.com>,
Andi Kleen <andi@firstfloor.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Stephane Eranian <eranian@google.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
Jiri Olsa <jolsa@redhat.com>
Subject: Re: [PATCH 05/33] perf record: Allow the user to disable time stamps
Date: Tue, 5 Aug 2014 08:08:56 +0200 [thread overview]
Message-ID: <20140805060856.GA9453@gmail.com> (raw)
In-Reply-To: <1407169064-25625-6-git-send-email-acme@kernel.org>
* Arnaldo Carvalho de Melo <acme@kernel.org> wrote:
> From: Andi Kleen <ak@linux.intel.com>
>
This patch looks dangerous and misleading to me.
> Time stamps are always implicitely enabled for record currently. The
> old --time/-T option is a nop.
>
> Allow the user to disable timestamps by using --no-time
>
> This can cause some minor misaccounting (by missing mmaps), but
> significantly lowers the size of perf.data
I'm not any big change in size:
-rw------- 1 mingo mingo 384768 Aug 5 08:01 perf.data.timestamps
-rw------- 1 mingo mingo 336952 Aug 5 08:00 perf.data.notimestamps
That's a ~14% reduction - it's certainly noticeable but not
earth-shattering.
And what is called 'minor misaccounting' in the description is
actually a potentially broken profile that people might rely on.
So the patch description misleads twice: by exaggerating the
advantages and also by downplaying the disadvantages.
So either remove the --time option altogether, or fix its
'misaccounting' so that the profile can be relied on.
Thanks,
Ingo
next prev parent reply other threads:[~2014-08-05 6:09 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-04 16:17 [GIT PULL 00/33] perf/core improvements and fixes Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 01/33] perf tools: Fix arm64 build error Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 02/33] perf evlist: Don't run workload if not told to Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 03/33] perf symbols: Make sure --symfs usage includes the path separator Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 04/33] perf kvm stat: Properly show submicrosecond times Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 05/33] perf record: Allow the user to disable time stamps Arnaldo Carvalho de Melo
2014-08-05 6:08 ` Ingo Molnar [this message]
2014-08-05 13:33 ` Arnaldo Carvalho de Melo
2014-08-12 14:58 ` Ingo Molnar
2014-08-12 15:29 ` Arnaldo Carvalho de Melo
2014-08-13 5:08 ` Ingo Molnar
2014-08-05 14:17 ` Andi Kleen
2014-08-05 14:31 ` Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 06/33] perf tools: Rename ordered_samples bool to ordered_events Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 07/33] perf tools: Rename ordered_samples struct " Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 08/33] perf tools: Rename ordered_events members Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 09/33] perf tools: Add ordered_events__(new|delete) interface Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 10/33] perf tools: Factor ordered_events__flush to be more generic Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 11/33] perf tools: Limit ordered events queue size Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 12/33] perf tools: Flush ordered events in case of allocation failure Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 13/33] perf tools: Make perf_session__deliver_event global Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 14/33] perf tools: Create ordered-events object Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 15/33] perf tools: Use list_move in ordered_events_delete function Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 16/33] perf tools: Add ordered_events__init function Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 17/33] perf tools: Add ordered_events__free function Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 18/33] perf tools: Add perf_config_u64 function Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 19/33] perf tools: Add report.queue-size config file option Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 20/33] perf tools: Add debug prints for ordered events queue Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 21/33] perf tools: Allow out of order messages in forced flush Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 22/33] perf tools: Show better error message in case we fail to open counters due to EBUSY error Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 23/33] perf kmem: Do not ignore mmap events Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 24/33] perf tools: Fix make PYTHON override Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 25/33] perf tools: Left-align output contents Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 26/33] perf tools: Make __hpp__fmt() receive an additional len argument Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 27/33] perf tools: Save column length in perf_hpp_fmt Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 28/33] perf report: Honor column width setting Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 29/33] perf top: Add -w option for setting column width Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 30/33] perf tools: Add name field into perf_hpp_fmt Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 31/33] perf tools: Fix column alignment when headers aren't shown on TUI Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 32/33] perf tools: Fix PERF_FLAG_FD_CLOEXEC flag probing event type open counters due to EBUSY error Arnaldo Carvalho de Melo
2014-08-04 16:17 ` [PATCH 33/33] perf tools: Default to python version 2 Arnaldo Carvalho de Melo
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