From: Andi Kleen <ak@linux.intel.com>
To: Mark Rutland <mark.rutland@arm.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Kan Liang <kan.liang@intel.com>,
Dmitri Prokhorov <Dmitry.Prohorov@intel.com>,
Valery Cherepennikov <valery.cherepennikov@intel.com>,
David Carrillo-Cisneros <davidcc@google.com>,
Stephane Eranian <eranian@google.com>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/n] perf/core: addressing 4x slowdown during per-process profiling of STREAM benchmark on Intel Xeon Phi
Date: Mon, 19 Jun 2017 08:39:18 -0700 [thread overview]
Message-ID: <20170619153918.GD23705@tassilo.jf.intel.com> (raw)
In-Reply-To: <20170619152400.GC4555@leverpostej>
On Mon, Jun 19, 2017 at 04:24:01PM +0100, Mark Rutland wrote:
> On Mon, Jun 19, 2017 at 08:21:51AM -0700, Andi Kleen wrote:
> > > I was trying to get a feel for how that compares to what we can do
> > > today. For other reasons (e.g. fd exhaustion), opening NR_CPUS * n
> >
> > You just have to increase the fd limit. The 1024 fd default is just
> > archaic for larger systems and doesn't really make any sense because
> > it only controls very small amounts of kernel memory.
> >
> > > events might not be a great idea on systems with a huge number of CPUs.
> > > We might want a heuristic in the perf tool regardless.
> >
> > But there's no alternative: we have to measure all CPUs with all events.
>
> You can measure the process on all CPUs by using 1 event without a CPU
> filter, rather than NR_CPUS events.
That wouldn't measure all threads, at least not with current perf core.
-Andi
next prev parent reply other threads:[~2017-06-19 15:39 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-15 17:41 [PATCH v3 1/n] perf/core: addressing 4x slowdown during per-process profiling of STREAM benchmark on Intel Xeon Phi Alexey Budankov
2017-06-15 19:56 ` Mark Rutland
2017-06-15 22:10 ` Alexey Budankov
2017-06-16 9:09 ` Mark Rutland
2017-06-16 14:08 ` Alexey Budankov
2017-06-16 14:22 ` Alexey Budankov
2017-06-19 12:46 ` Mark Rutland
2017-06-19 13:38 ` Mark Rutland
2017-06-19 14:09 ` Alexey Budankov
2017-06-19 14:59 ` Andi Kleen
2017-06-19 15:09 ` Mark Rutland
2017-06-19 15:21 ` Andi Kleen
2017-06-19 15:24 ` Mark Rutland
2017-06-19 15:39 ` Andi Kleen [this message]
2017-06-19 15:52 ` Mark Rutland
2017-06-19 13:08 ` Alexey Budankov
2017-06-19 13:26 ` Mark Rutland
2017-06-19 13:37 ` Alexey Budankov
2017-06-19 15:00 ` Alexey Budankov
2017-06-19 15:24 ` Andi Kleen
2017-06-19 15:34 ` Alexey Budankov
2017-06-30 10:23 ` Alexey Budankov
2017-06-30 10:21 ` Alexey Budankov
2017-06-19 15:14 ` Mark Rutland
2017-06-19 15:27 ` Alexey Budankov
2017-06-30 10:21 ` Alexey Budankov
2017-06-19 20:31 ` Alexey Budankov
2017-06-20 13:36 ` Mark Rutland
2017-06-20 15:22 ` Alexey Budankov
2017-06-20 16:37 ` Mark Rutland
2017-06-20 17:10 ` Alexey Budankov
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