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Date: Wed, 17 May 2017 22:10:43 -0700
From: Andi Kleen <ak@linux.intel.com>
To: David Carrillo-Cisneros <davidcc@google.com>
Cc: linux-kernel@vger.kernel.org, Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Simon Que <sque@chromium.org>, Wang Nan <wangnan0@huawei.com>,
        Jiri Olsa <jolsa@kernel.org>, He Kuang <hekuang@huawei.com>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        David Ahern <dsa@cumulusnetworks.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Stephane Eranian <eranian@google.com>, Paul Turner <pjt@google.com>
Subject: Re: [PATCH 0/7] perf tool: add meta-data header support for pipe-mode
Message-ID: <20170518051043.GA15563@tassilo.jf.intel.com>
References: <20170518041602.28689-1-davidcc@google.com>
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> The difficulty in pipe mode is that information needs to be written
> sequentially to the pipe. Meta data headers are usually generated
> (and also expected) at the beginning of the file (or piped output).
> To solve this problem, we introduce new synthetic record types,
> one for each meta-data type. The approach is similar to what
> is *ALREADY* used for BUILD_ID and TRACING_DATA.

The new headers need documentation in Documentation/perf.data-file-format.txt

-Andi