Message-ID: <555BAE33.5060502@plumgrid.com>
Date: Tue, 19 May 2015 14:42:11 -0700
From: Alexei Starovoitov <ast@plumgrid.com>
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To: Arnaldo Carvalho de Melo <acme@kernel.org>
CC: Namhyung Kim <namhyung@kernel.org>, Wang Nan <wangnan0@huawei.com>,
        paulus@samba.org, a.p.zijlstra@chello.nl, mingo@redhat.com,
        jolsa@kernel.org, dsahern@gmail.com, daniel@iogearbox.net,
        brendan.d.gregg@gmail.com, masami.hiramatsu.pt@hitachi.com,
        lizefan@huawei.com, linux-kernel@vger.kernel.org, pi3orama@163.com
Subject: Re: [RFC PATCH v3 00/37] perf tools: introduce 'perf bpf' command
 to load eBPF programs.
References: <1431860222-61636-1-git-send-email-wangnan0@huawei.com> <555A3FC2.8060805@plumgrid.com> <20150518204416.GJ18563@kernel.org> <555A541F.6090606@plumgrid.com> <20150518212013.GB13946@kernel.org> <555A5D96.2070509@plumgrid.com> <20150519134458.GC13946@kernel.org> <20150519160448.GD29162@danjae.kornet> <20150519164040.GB19921@kernel.org> <555BA112.6090505@plumgrid.com> <20150519211033.GF19921@kernel.org>
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On 5/19/15 2:10 PM, Arnaldo Carvalho de Melo wrote:
>
> This all should use infrastructure in perf for symbol resolving,
> callcahins, etc.

yes. 100%

> Right, but if we do a:
>
> perf script -i perf.data bpf_file.c
>
> Then there would be a short circuit effect of just doing the
> aggregation and/or reporting.

That can work, but I don't see why I would use bpf for
scripting on top of perf.data. If trace is already collected,
the existing perl/python scripts will work fine.

> Well, we could have a tee like mode where perf.data file could be
> generated so that we could run it again after doing some change on the
> aggregation code, so that we wouldn't have to re-run the data collection
> parts, that could be about some condition hard to capture, etc.

true, but again I don't think in such scenario you'd need bpf.
bpf is needed when the number of events is huge and the user
needs to aggregate/process them in-kernel.

>> I guess I'm saying let's not get too much ahead of ourselves ;)
>
> No problem, but then we need to talk at this moment not to add new stuff
> that we think should not be added, like 'perf bpf' :-)

ahh, that's where you going :) Sure. I don't mind avoiding that
unbearable abbreviation if we can :)
'perf script file.[oc]' command line works for me.

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