Re: [PATCH 03/31] perf tools: Enable passing bpf object file to --event

From: Arnaldo Carvalho de Melo
Date: Tue Oct 20 2015 - 11:16:12 EST


Em Tue, Oct 20, 2015 at 12:12:55PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Wed, Oct 14, 2015 at 12:41:14PM +0000, Wang Nan escreveu:
> > By introducing new rules in tools/perf/util/parse-events.[ly], this
> > patch enables 'perf record --event bpf_file.o' to select events by an
> > eBPF object file. It calls parse_events_load_bpf() to load that file,
> > which uses bpf__prepare_load() and finally calls bpf_object__open() for
> > the object files.
> >
> > After applying this patch, commands like:
> >
> > # perf record --event foo.o sleep
> >
> > become possible.
>
> So, trying the above command I get almost perfect output:
>
> [root@felicio ~]# perf record --event foo.o sleep
> libbpf: failed to open foo.o: No such file or directory
> event syntax error: 'foo.o'
> \___ BPF object file 'foo.o' is invalid
>
> (add -v to see detail)
> Run 'perf list' for a list of valid events
>
> Usage: perf record [<options>] [<command>]
> or: perf record [<options>] -- <command> [<options>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> [root@felicio ~]#
>
>
> Good thing would be to not have any message from libbpf and the right error
> message from the parser, i.e. the first three lines become these two:
>
>
> event syntax error: 'foo.o'
> \___ BPF object file 'foo.o' not found.o
>
> But that can be fixed up in an upcoming patch, so I am applying this one now in
> my new attempt at processing this patchkit.

Ditto for:

[acme@felicio linux]$ perf record --event /tmp/build/perf/perf.o sleep
libbpf: /tmp/build/perf/perf.o is not an eBPF object file
event syntax error: '/tmp/build/perf/perf.o'
\___ BPF object file '/tmp/build/perf/perf.o' is invalid

(add -v to see detail)
Run 'perf list' for a list of valid events

Usage: perf record [<options>] [<command>]
or: perf record [<options>] -- <command> [<options>]

-e, --event <event> event selector. use 'perf list' to list available events
[acme@felicio linux]$

Now trying to find a _valid_ ebpf object file to test with.

- Arnaldo
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