Re: [RFC PATCH v3 00/37] perf tools: introduce 'perf bpf' command to load eBPF programs.

From: Alexei Starovoitov
Date: Tue May 19 2015 - 17:42:22 EST


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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