Messages in this thread | | | Date | Sun, 7 Jul 2013 16:56:04 +0200 | From | Jiri Olsa <> | Subject | Re: perf/Documentation/ABI -- add some documentation for perf_event sysfs usage |
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On Fri, Jul 05, 2013 at 11:28:08AM -0400, Vince Weaver wrote: > On Fri, 5 Jul 2013, Jiri Olsa wrote: > > > On Thu, Jul 04, 2013 at 11:02:53AM +0200, Peter Zijlstra wrote: > > > On Wed, Jul 03, 2013 at 11:14:40PM -0400, Vince Weaver wrote: > > > > > Documentation/ABI/testing/sysfs-bus-event_source-devices-events > > > > > > > > Should the ldlat value be fixed to be hex? Or should we ammend the ABI > > > > document to allow decimal? > > > > > > I don't see a good reason not to allow decimal as well. Jolsa? > > > > yep, no technical problem with decimal > > > > hum, the doc mentions 'event' term only, which IS hex only AFAICS ;-) > > > > I think this docs should be updated and either describe all > > allowed terms or be generic enough to cover all of them. > > So you're saying the official kernel ABI should be "whatever the > userspace perf tool happens to accept"?
nope, I meant whatever term is used by kernel to describe the event
'event, umask, edge, pc, any, inv, cmask, ldat'
please check x86_event_sysfs_show function
> > That's not really useful, especially as perf doesn't distinguish between > event strings read from sysfs and those passed on the perf command line. > The ABI documentation in effect ends up being a pointer to a mostly > incomprehensible lex/yacc file.
the documentation is missing, no argument here :-\ 'sysfs-bus-event_source-devices-events' could be more descriptive
> > I think we should just remove the > Documentation/ABI/testing/sysfs-bus-event_source-devices-events > file as it's misleading. Userspace broke and no one cares. > > It's not even easy to audit all places in the kernel that create the sysfs > event files because each architecture does it differently. And there's no > sane way to unit test this on a new kernel release because the values > printed depend on the hardware you have, so without a full range of all > families of cpus for all architectures you never know when someone has > added a decimal value, or started depending on { characters, etc. > > This is the problem with perf in the tools directory, any other user of > the ABI is eternally second-class.
with updated documentation I dont see the issue
jirka
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