Messages in this thread | | | Date | Wed, 21 Oct 2015 09:55:43 +0800 | From | "Wangnan (F)" <> | Subject | Re: [PATCH 03/31] perf tools: Enable passing bpf object file to --event |
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On 2015/10/20 23:15, Arnaldo Carvalho de Melo wrote: > 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.
I think fixing that is not very hard. When designing libbpf, I thought the problem like this so makes libbpf output controled by caller using 'libbpf_set_print()'. What we need to do is to pass different output functions to libbpf. We can easily disable all output from libbpf if verbose is set 0. The only question is: do you want me to provide a new version of patch 'perf ebpf: Add the libbpf glue' or you prefer another patch to adjust the output functions?
Thank you.
> 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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