Re: perf & rasd integration plan

[Arnaldo Carvalho de Melo <acme@kernel.org>]

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