* Steven Rostedt <[email protected]> wrote:
> On Tue, 9 Jun 2015 15:51:53 -0400 (EDT)
> Vince Weaver <[email protected]> wrote:
>
> > On Tue, 9 Jun 2015, David Ahern wrote:
> >
> > > On 6/9/15 12:30 PM, Vince Weaver wrote:
> > > > Hello
> > > >
> > > > I've been working on documenting the PERF_EVENT_IOC_SET_FILTER ioctl.
> > > >
> > > > I've been trying for the past 2 days and have been unable to get any
> > > > result except EINVAL.
> > > >
> > > > Does anyone ever use this ioctl? Does anyone know how to use this
> > > > ioctl?
> > >
> > > yes and yes it works.
> > >
> > > perf record -e irq:irq_handler_entry --filter irq==28 \
> > > -e irq:softirq_entry --filter vec==6 -a \
> > > -- sleep 5
> >
> > # perf record -e irq:irq_handler_entry --filter irq==28 -e
> > irq:softirq_entry --filter vec==6 -a -- sleep 5
> > invalid or unsupported event: 'irq:irq_handler_entry'
> > Run 'perf list' for a list of valid events
> >
> > perf list doesn't show any tracepoint events, despite having debugfs
> > mounted and running as root and /sys/kernel/debug/tracing/events/ being
> > populated.
> >
>
> What kernel are you using? You may need to update perf.
>
> We switched to a tracefs filesystem, but the old perf wont read any events if
> it's not located in debugfs. That is, it actually tested which filesystem the
> event files were mounted on, and if they didn't match the debugfs mount type,
> it
> ignored them. That was fixed recently.
That fix should probably be backported to stable kernels, to keep old instances
working.
Thanks,
Ingo
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