From: David Ahern <dsahern@gmail.com>
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
Cc: Yunlong Song <yunlong.song@huawei.com>,
a.p.zijlstra@chello.nl, paulus@samba.org, mingo@redhat.com,
linux-kernel@vger.kernel.org, wangnan0@huawei.com,
namhyung@kernel.org, ast@kernel.org,
masami.hiramatsu.pt@hitachi.com, kan.liang@intel.com,
adrian.hunter@intel.com, jolsa@kernel.org, bp@alien8.de,
jean.pihet@linaro.org, rric@kernel.org, xiakaixu@huawei.com,
hekuang@huawei.com
Subject: Re: [PATCH] perf record: Add snapshot mode support for perf's regular events
Date: Tue, 24 Nov 2015 09:16:11 -0700 [thread overview]
Message-ID: <56548D4B.1090403@gmail.com> (raw)
In-Reply-To: <20151124154025.GF18140@kernel.org>
On 11/24/15 8:40 AM, Arnaldo Carvalho de Melo wrote:
> perf-record without his patch? yes, but with his patch it does:
>
> __cmd_record()
> for (;;)
> record__mmap_read_all()
> record__write()
> perf_memory__write()
> event = (union perf_event *)(memory->start + memory->head + skip);
> if (event->header.type != PERF_RECORD_SAMPLE) {
> if (buf_to_file(rec, memory->start, memory->size,
> }
>
> I almost thought that I had been fooled by the difficulty to follow his
> patch and was forgetting that 'perf record' doesn't processes events,
> and hasn't done so for a very good reason: to reduce its impact on the
> observed workload, but that ain't so, no?
exactly. And I missed the above. Thanks for pointing that out.
next prev parent reply other threads:[~2015-11-24 16:16 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-24 14:00 [PATCH] perf record: Add snapshot mode support for perf's regular events Yunlong Song
2015-11-24 14:00 ` Yunlong Song
2015-11-24 14:30 ` Arnaldo Carvalho de Melo
2015-11-25 12:44 ` Yunlong Song
2015-11-24 15:06 ` David Ahern
2015-11-24 15:20 ` Arnaldo Carvalho de Melo
2015-11-24 15:24 ` David Ahern
2015-11-24 15:40 ` Arnaldo Carvalho de Melo
2015-11-24 16:16 ` David Ahern [this message]
2015-11-25 3:50 ` Wangnan (F)
2015-11-25 5:06 ` David Ahern
2015-11-25 7:22 ` Adrian Hunter
2015-11-25 7:47 ` Wangnan (F)
2015-11-25 8:27 ` Adrian Hunter
2015-11-25 8:43 ` Wangnan (F)
2015-11-25 9:05 ` Adrian Hunter
2015-11-25 7:50 ` Yunlong Song
2015-11-25 9:27 ` Peter Zijlstra
2015-11-25 9:44 ` Wangnan (F)
2015-11-25 12:20 ` Peter Zijlstra
2015-11-25 12:54 ` Wangnan (F)
2015-11-26 9:19 ` Ingo Molnar
2015-11-26 9:24 ` Wangnan (F)
2015-11-26 9:27 ` Ingo Molnar
2015-11-26 9:40 ` Ingo Molnar
2015-11-26 9:57 ` Ingo Molnar
2015-12-02 8:25 ` Wangnan (F)
2015-12-02 13:38 ` [RFC PATCH] perf/core: Put size of a sample at the end of it Wang Nan
2015-12-03 10:08 ` Peter Zijlstra
2015-12-03 10:31 ` Wangnan (F)
2015-12-07 13:28 ` [RFC PATCH v2 0/3] perf core/perf tools: Utilizing overwrite ring buffer Wang Nan
2015-12-07 13:28 ` [RFC PATCH v2 1/3] perf/core: Put size of a sample at the end of it Wang Nan
2015-12-07 13:28 ` [RFC PATCH v2 2/3] perf tools: Enable overwrite settings Wang Nan
2015-12-07 13:28 ` [RFC PATCH v2 3/3] perf record: Find tail pointer through size at end of event Wang Nan
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