Re: perf & rasd integration plan

Arnaldo Carvalho de Melo
2014-09-30T13:24:24Z

Em Tue, Sep 30, 2014 at 11:06:21AM +0200, Jean Pihet escreveu:
> The RAS Deamon (rasd) as available at [1] and the development version
> at [2], allows to enable kernel tracepoints and outputs the
> tracepoints fields according to the kernel format.
>
> [1] https://git.kernel.org/cgit/utils/ras/rasd.git/
> [2] https://git.linaro.org/people/jean.pihet/rasd.git
>
> rasd currently is a duplicate of the perf tool code, ultimately perf
> and rasd will use the same common code. The goal is to factor out the
> common code from perf and place it in small librairies in tools/lib.
>
> Here is the code that rasd currently uses and that should be moved to tools/lib:
>
> - debugfs: already in tools/lib/api/fs
> . mount and retrieve path
>
> - evlist: tools/perf/util/evlist.[ch]
> . create and init new evlist,
> . set cpu and thread maps,
> . add events to evlist,
> . init and use internal event id,
> . alloc and mmap events buffers, manage file descriptors,
> . enable events,
> . read events buffers, parse data,
> . unmap and free buffers
>
> - evsel: tools/perf/util/evsel.[ch]
> . create and init new tracepoints events,
> . init and use internal event id,
> . open events, manage fds,
> . close and free events
>
> - trace-event: tools/perf/util/trace-event.[ch] and
> tools/perf/util/trace-event-parse.c
> . retrieve and parse events format (using event-parse),
> . print out events fields
>
> - event-parse: already in tools/lib/traceevent/event-parse.[ch]
> . retrieve and parse events format,
> . parse events format and print out events fields
>
> - trace-seq: already in tools/lib/traceevent/trace-seq.c
> . format output string for event fields
>
> - events plugins: already in tools/lib/traceevent/event-plugin.c
>
> - util: tools/perf/util/util.[ch]
> . files open/read,
> . manage events attributes,
> . various macros
>
> - test events attributes: tools/perf/tests/attr.c
> . test_attr__open()
>
> - thread: tools/perf/util/thread_map.[ch] and
> - cpu: tools/perf/util/cpumap.[ch]
> . init and manage process maps
>
> - xyarray: tools/perf/util/xyarray.[ch]
>
> - syscall: tools/perf/perf-sys.h
>
> - cgroup: tools/perf/util/cgroup.[ch]
>
> The plan is to move the small and generic functions first: util,
> xyarray, cpumap, thread_map etc; then evlist, evsel, trace-event,
> trace-event-parse; and finally integrate rasd into the tools/ dir.
>
> Any thought? Can evlist, evsel etc. be moved at once?
>
> Patches should come soon, when time allows.

Why don't you add it to tools/rasd/ and in tools/rasd/Makefile you just
go on and add tools/perf/util/evlist.o et all to be linked directly, as
a first step.

Then, as a second step, we can create a tools/lib/perf/evlist.c having
what is currently used by both tools/perf/ and tools/rasd/, i.e. what is
proven to be useful for something other than perf.

As the need arises, we go on moving things into tools/lib/perf/evlist.c
et all from wherever it appeared first, be it from tools/rasd/,
tools/perf/util/evlist.c or anywhere else.

Initial rule being that once it is used by multiple tools living in
tools/, then it deserves a place in tools/lib/perf/.

Ditto for other stuff currently living in tools/perf/util/.

- Arnaldo