Subject: Re: [PATCH] perf record: Add snapshot mode support for perf's regular
 events
To: Arnaldo Carvalho de Melo <arnaldo.melo@gmail.com>
References: <1448373632-8806-1-git-send-email-yunlong.song@huawei.com>
 <1448373632-8806-2-git-send-email-yunlong.song@huawei.com>
 <56547D01.8020606@gmail.com> <20151124152023.GE18140@kernel.org>
 <56548117.9080704@gmail.com> <20151124154025.GF18140@kernel.org>
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
From: David Ahern <dsahern@gmail.com>
Message-ID: <56548D4B.1090403@gmail.com>
Date: Tue, 24 Nov 2015 09:16:11 -0700
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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.
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