From: Matt Fleming <matt@console-pimps.org>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Zhang Rui <rui.zhang@intel.com>,
linux-kernel@vger.kernel.org, Ingo Molnar <mingo@elte.hu>,
Frederic Weisbecker <fweisbec@gmail.com>,
Robert Richter <robert.richter@amd.com>,
Lin Ming <ming.m.lin@intel.com>,
Paul Mackerras <paulus@samba.org>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Don Zickus <dzickus@redhat.com>,
Cyrill Gorcunov <gorcunov@gmail.com>, Len Brown <lenb@kernel.org>,
Matthew Garrett <mjg59@srcf.ucam.org>
Subject: Re: [RFC][PATCH 3/5] perf: Add hrtimer code for PMI-less hardware counters
Date: Mon, 30 Aug 2010 20:35:58 +0100 [thread overview]
Message-ID: <20100830193558.GE24828@console-pimps.org> (raw)
In-Reply-To: <1283177544.1820.992.camel@laptop>
On Mon, Aug 30, 2010 at 04:12:24PM +0200, Peter Zijlstra wrote:
> On Mon, 2010-08-30 at 14:27 +0100, Matt Fleming wrote:
>
> > I'm lost. Is it possible to do this patch entirely in userspace? How do
> > we periodically sample the counters if it's not being done in the
> > kernel?
>
> perf_event_attr leader = {
> .type = PERF_TYPE_SOFTWARE,
> .config = PERF_COUNT_SW_TASK_CLOCK,
> .sample_period = xxx,
> .sample_type = PERF_SAMPLE_READ|...,
> .read_format = PERF_FORMAT_GROUP,
> };
>
> perf_event_attr counter = {
> .type = PERF_TYPE_HARDWARE,
> .config = PERF_COUNT_HW_CPU_CYCLES,
> };
>
> leader_fd = sys_perf_event_open(&leader, pid, cpu, 0, 0);
> counter_fd = sys_perf_event_open(&counter, pid, cpu, leader_fd, 0);
>
> Which gives you a group of 2 events, one software timer that samples,
> one hardware counter that only counts.
Aha. OK, thanks! I'll respin this.
next prev parent reply other threads:[~2010-08-30 19:36 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-30 12:13 [RFC][PATCH 0/5] hrtimer group events Matt Fleming
2010-08-30 12:13 ` [RFC][PATCH 1/5] perf: Check if we should exclude idle thread in perf_exclude_event() Matt Fleming
2010-08-31 14:54 ` Frederic Weisbecker
2010-08-31 15:20 ` Matt Fleming
2010-08-31 15:21 ` Frederic Weisbecker
2010-08-30 12:13 ` [RFC][PATCH 2/5] perf: Turn the group counter values into delta values Matt Fleming
2010-08-30 12:54 ` Peter Zijlstra
2010-08-30 13:21 ` Matt Fleming
2010-08-30 12:13 ` [RFC][PATCH 3/5] perf: Add hrtimer code for PMI-less hardware counters Matt Fleming
2010-08-30 12:55 ` Peter Zijlstra
2010-08-30 13:27 ` Matt Fleming
2010-08-30 14:12 ` Peter Zijlstra
2010-08-30 19:35 ` Matt Fleming [this message]
2010-08-30 12:13 ` [RFC][PATCH 4/5] sh: Add support for sampling counters Matt Fleming
2010-08-30 12:13 ` [RFC][PATCH 5/5] perf: Add support for PERF_SAMPLE_READ samples Matt Fleming
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