lkml.org 
[lkml]   [2019]   [Jul]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [RFC 00/79] perf tools: Initial libperf separation
Date
Hi Jiri,

> On Jul 21, 2019, at 4:23 AM, Jiri Olsa <jolsa@kernel.org> wrote:
>
> hi,
> we have long term goal to separate some of the perf functionality
> into library. This patchset is initial effort on separating some
> of the interface.
>
> Currently only the basic counting interface is exported, it allows
> to:
> - create cpu/threads maps
> - create evlist/evsel objects
> - add evsel objects into evlist
> - open/close evlist/evsel objects
> - enable/disable events
> - read evsel counts

Based on my understanding, evsel and evlist are abstractions in
perf utilities. I think most other tools that use perf UAPIs are
not built based on these abstractions. I looked at a few internal
tools. Most of them just uses sys_perf_event_open() and struct
perf_event_attr. I am not sure whether these tools would adopt
libperf, as libperf changes their existing concepts/abstractions.

>
> The initial effort was to have total separation of the objects
> from perf code, but it showed not to be a good way. The amount
> of changed code was too big with high chance for regressions,
> mainly because of the code embedding one of the above objects
> statically.
>
> We took the other approach of sharing the objects/struct details
> within the perf and libperf code. This way we can keep perf
> functionality without any major changes and the libperf users
> are still separated from the object/struct details. We can move
> to total libperf's objects separation gradually in future.

I found some duplicated logic between libperf and perf, for
example, perf_evlist__open() and evlist__open(). Do we plan to
merge them in the future?

Thanks,
Song

\
 
 \ /
  Last update: 2019-07-24 09:43    [W:0.489 / U:48.584 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site