Hi Jiri, > On Jul 21, 2019, at 4:23 AM, Jiri Olsa <jo...@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
