From: Ingo Molnar <mingo@kernel.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Jiri Olsa <jolsa@redhat.com>,
linux-kernel@vger.kernel.org,
Corey Ashford <cjashfor@linux.vnet.ibm.com>,
Frederic Weisbecker <fweisbec@gmail.com>,
Ingo Molnar <mingo@elte.hu>, Namhyung Kim <namhyung@kernel.org>,
Paul Mackerras <paulus@samba.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Andi Kleen <ak@linux.intel.com>, David Ahern <dsahern@gmail.com>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 0/9] perf: Adding better precise_ip field handling
Date: Fri, 10 May 2013 12:18:23 +0200 [thread overview]
Message-ID: <20130510101823.GA18427@gmail.com> (raw)
In-Reply-To: <20130510095345.GG3039@dyad.programming.kicks-ass.net>
* Peter Zijlstra <peterz@infradead.org> wrote:
> > so you mean just detect that by opening events with increasing precise
> > and see how far we could get.. could be I guess, though the 'precise'
> > sysfs attribute seems more fit to me
>
> The other way around, start at ppp end at !p, then use the one that
> worked.
Really, instead of this silly 'probing until it works' notion, how about
the radical idea that we pass to the kernel our request, and the kernel
fulfills our wish to the best of its ability?
This could be done as a new PERF_COUNT_HW_CPU_CYCLES_PRECISE event, to
which tooling could migrate, without changing existing semantics.
The problem with the complex probing is that it's totally unnecessary
complexity that results from lack of passing the right information to the
kernel. Forcing that will only hinder user-space adoption of our precise
profiling facilities.
Thanks,
Ingo
next prev parent reply other threads:[~2013-05-10 10:18 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-09 13:32 [PATCH 0/9] perf: Adding better precise_ip field handling Jiri Olsa
2013-05-09 13:32 ` [PATCH 1/9] perf x86: Add precise sysfs cpu pmu attribute Jiri Olsa
2013-05-09 13:32 ` [PATCH 2/9] perf tools: Add precise object to interface sysfs precise Jiri Olsa
2013-05-10 1:34 ` Namhyung Kim
2013-05-10 9:06 ` Jiri Olsa
2013-05-09 13:32 ` [PATCH 3/9] perf tests: Add precise event automated test Jiri Olsa
2013-05-09 13:32 ` [PATCH 4/9] perf tools: Add a precise event qualifier Jiri Olsa
2013-05-10 1:43 ` Namhyung Kim
2013-05-10 9:10 ` Jiri Olsa
2013-05-09 13:32 ` [PATCH 5/9] perf tools: Set maximum precise value for event 'p' modifier Jiri Olsa
2013-05-09 19:43 ` David Ahern
2013-05-10 9:12 ` Jiri Olsa
2013-05-10 1:53 ` Namhyung Kim
2013-05-10 9:16 ` Jiri Olsa
2013-05-09 13:32 ` [PATCH 6/9] perf tools: Set maximum precise value for 'precise' term Jiri Olsa
2013-05-09 13:32 ` [PATCH 7/9] perf tests: Add automated precise term test Jiri Olsa
2013-05-09 13:32 ` [PATCH 8/9] perf: Document the ABI for 'precise' sysfs attribute Jiri Olsa
2013-05-10 1:57 ` Namhyung Kim
2013-05-09 13:32 ` [PATCH 9/9] perf: Document the ABI for 'rdpmc' " Jiri Olsa
2013-05-09 15:07 ` [PATCH 0/9] perf: Adding better precise_ip field handling Peter Zijlstra
2013-05-09 15:20 ` Jiri Olsa
2013-05-10 9:27 ` Peter Zijlstra
2013-05-10 9:40 ` Jiri Olsa
2013-05-10 9:53 ` Peter Zijlstra
2013-05-10 10:18 ` Ingo Molnar [this message]
2013-05-10 10:22 ` Peter Zijlstra
2013-05-10 10:31 ` Ingo Molnar
2013-05-10 10:34 ` Peter Zijlstra
2013-05-10 10:55 ` Ingo Molnar
2013-05-10 11:27 ` Peter Zijlstra
2013-05-11 7:50 ` Ingo Molnar
2013-05-13 9:36 ` Peter Zijlstra
2013-05-13 19:43 ` Ingo Molnar
2013-05-14 7:22 ` Peter Zijlstra
2013-05-14 8:37 ` Ingo Molnar
2013-05-14 8:36 ` Gleb Natapov
2013-05-15 13:27 ` Stephane Eranian
2013-05-28 9:54 ` Ingo Molnar
2013-05-10 9:29 ` Peter Zijlstra
2013-05-10 9:43 ` Jiri Olsa
-- strict thread matches above, loose matches on Subject: below --
2013-01-26 17:27 Jiri Olsa
2013-01-26 18:53 ` Jiri Olsa
2013-01-27 12:41 ` Ingo Molnar
2013-01-27 12:57 ` Jiri Olsa
2013-01-27 13:02 ` Ingo Molnar
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