From: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
To: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>,
linux-kernel@vger.kernel.org,
Frederic Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <peterz@infradead.org>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Mike Galbraith <efault@gmx.de>,
Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 3/3] perf record: mmap output file
Date: Tue, 15 Oct 2013 11:32:45 -0300 [thread overview]
Message-ID: <20131015143245.GB9828@ghostprotocols.net> (raw)
In-Reply-To: <525D4B5F.4090005@gmail.com>
Em Tue, Oct 15, 2013 at 08:04:15AM -0600, David Ahern escreveu:
> On 10/8/13 11:59 PM, Ingo Molnar wrote:
> > 2)
> > Yet another method would be to avoid the copies altogether via the splice
> > system-call - see:
> > git grep splice kernel/trace/
> > To make splice low-overhead we'd have to introduce a mode to not mmap
> > the data part of the perf ring-buffer and splice the data straight
> > from the perf fd into a temporary pipe and over from the pipe into
> > the target file (or socket).
> I looked into splice and it was not clear it would be a good match.
> First, perf is setup to pull data from mmap's and there is not a 1:1
> association between mmap's and fd's (fd_in for splice). Second and
Jiri and PeterZ probaby will have comments here... ;-) :-)
Jiri even have patches, IIRC.
- Arnaldo
next prev parent reply other threads:[~2013-10-15 14:32 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-09 3:26 [PATCH 0/3] perf trace enhancements David Ahern
2013-10-09 3:26 ` [PATCH 1/3] perf util: Add findnew method to intlist - v2 David Ahern
2013-10-15 5:32 ` [tip:perf/core] perf util: Add findnew method to intlist tip-bot for David Ahern
2013-10-09 3:26 ` [PATCH 2/3] perf trace: Add summary option to dump syscall statistics David Ahern
2013-10-09 13:16 ` Jiri Olsa
2013-10-15 5:32 ` [tip:perf/core] " tip-bot for David Ahern
2013-10-09 3:26 ` [PATCH 3/3] perf record: mmap output file David Ahern
2013-10-09 5:59 ` Ingo Molnar
2013-10-15 14:04 ` David Ahern
2013-10-15 14:32 ` Arnaldo Carvalho de Melo [this message]
2013-10-15 14:38 ` Peter Zijlstra
2013-10-15 15:27 ` Ingo Molnar
2013-10-15 15:29 ` Peter Zijlstra
2013-10-15 15:30 ` David Ahern
2013-10-15 16:06 ` Ingo Molnar
2013-10-15 16:16 ` David Ahern
2013-10-16 7:11 ` Ingo Molnar
2013-10-15 16:37 ` Peter Zijlstra
2013-10-09 7:14 ` Mike Galbraith
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