| Date | Mon, 18 May 2015 12:38:42 -0700 | From | Alexei Starovoitov <> | Subject | Re: [RFC PATCH v3 00/37] perf tools: introduce 'perf bpf' command to load eBPF programs. |
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On 5/17/15 3:56 AM, Wang Nan wrote: > This is the 3rd version of 'perf bpf' patch series, based on > v4.1-rc3. > > The goal of this series of patches is to integrate eBPF with perf. > After applying these patches, users are allowed to use following > command to load eBPF program compiled by LLVM into kernel then start > recording with filters on: > > # perf bpf record --object sample_bpf.o -- -a sleep 4
I think using programs are sophisticated filters is a good start and are useful already. Let's focus on that at the moment. I wouldn't grow the patchset any bigger.
> Other than the previous change, v3 patch series drops the '|' event > syntax introduced in v2, because I realized that in v2 users are > allowed to pass any bpf fd by using it, like: > > # perf bpf record -- -e sched:sched_switch|100| sleep 1 > > which may become trouble maker.
passing fd number as a string is an odd interface anyway. So I think that was the right call. We can improve it later.
> Are we actually need a 'perf bpf' command? We can get similar result by > modifying 'perf record' to make it load eBPF program before recording. > > I suggest to keep 'perf bpf', group all eBPF stuffs together using a > uniform entry. Also, eBPF programs can act not only as filters but also > data aggregator. It is possible to make something link 'perf bpf run' > to simply make it run, and dump result after user hit 'C-c' or timeout.
Though it's tempting to group under 'perf bpf'. I think it's cleaner to add --object flag to 'perf record' Since it will avoid unnecessary '--'. Unless we can drop it? Like perf bpf record --object sample_bpf.o -a sleep 4 should work? If not, then the following is better: perf record --object sample_bpf.o -a sleep 4
Thank you for the hard work!
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