Re: libperf: lack of interface

[nakamura.shun@xxxxxxxxxxx]

Hi jirka

> > > On Mon, Oct 18, 2021 at 08:57:20AM +0000, nakamura.shun@xxxxxxxxxxx wrote:
> > > > Hi
> > > > 
> > > > > > On Wed, Sep 01, 2021 at 10:36:40AM -0300, Arnaldo Carvalho de Melo wrote:
> > > > > > > Em Wed, Sep 01, 2021 at 09:45:10AM +0000, nakamura.shun@xxxxxxxxxxx escreveu:
> > > > > > > > Hello.
> > > > > > > >
> > > > > > > > I'm trying to change rdpmc test in perf_event_tests[1] to use libperf, but libperf doesn't have enough interfaces.
> > > > > > > > Does anyone plan to implement any of these libperf features?
> > > > > > > >
> > > > > > > > - Interfaces that can run ioctl (PERF_EVENT_IOC_RESET) from userland
> > > > > > > > - Interfaces that can run fcntl (SIGIO) from userland
> > > > > >
> > > > > > hi,
> > > > > > we could add perf_evsel__fd like below, would it help your usecase?
> > > > > >
> > > > > > if you described your usecases in more details we could
> > > > > > see if we could add/move something to libperf for that
> > > > > >
> > > > > > as Arnaldo said below it could be already in tools/perf/util/*.c
> > > > > > somewhere ;-)
> > > > > 
> > > > > As Peter says, I understood that for rdpmc, no reset is needed.
> > > > > 
> > > > > However, PAPI resets it explicitly, for example, at PAPI_reset.
> > > > > In other, PAPI also has the ability to call PERF_EVENT_IOC_REFLESH on overflow to call a user-registered handler, using SIGIO.
> > > > > 
> > > > > I think it is desirable to be able to achieve similar functionality.
> > > > 
> > > > Does anyone have any comments?
> > > 
> > > I'll try to add that functionality soon,
> > > I'll cc you on patch
> > 
> > Thank you.
> > I look forward to your patch.
> 
> Do you have a specific plan? 
> I would like to know the rough period until your patch is made.
 
I will also try to implement these interfaces.

Best Regards
Shunsuke