Messages in this thread |  | | From | Stephane Eranian <> | Date | Tue, 30 Nov 2021 16:36:49 -0800 | Subject | Re: [RFC/PATCHSET 0/5] perf ftrace: Implement function latency histogram (v1) |
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On Tue, Nov 30, 2021 at 2:58 PM Namhyung Kim <namhyung@kernel.org> wrote: > > Hi Arnaldo, > > On Tue, Nov 30, 2021 at 6:37 AM Arnaldo Carvalho de Melo > <acme@kernel.org> wrote: > > > > Em Mon, Nov 29, 2021 at 03:18:25PM -0800, Namhyung Kim escreveu: > > > Hello, > > > > > > I've implemented 'latency' subcommand in the perf ftrace command to > > > show a histogram of function latency. > > > > > > To handle new subcommands, the existing functionality is moved to > > > 'trace' subcommand while preserving backward compatibility of not > > > having a subcommand at all (defaults to 'trace'). > > > > > > The latency subcommand accepts a target (kernel, for now) function > > > with -T option and shows a histogram like below: > > > > Humm, wouldn't be interesting to shorten this by having a new 'perf > > flat' (function latency) tool, on the same level as 'perf ftrace' and > > leave 'perf ftrace' to just being a convenient perf interface to what > > ftrace provides? > > That would be fine. I also think 'perf ftrace latency' is > bit too long. But if we would add a new feature > like argdist (in BCC) later, I thought it'd be nice being > a subcommand in the perf ftrace together. > > But it's up to you. I'll make a change if you prefer > 'flat' (or how about 'fnlat' instead?). > I am not too fond of the flat option because as we had more bpf tools like function latency, then we keep extending the list of commands each with a small span which is different from what we have right now.
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