Re: perf: multiple mmap of fd behavior on x86/ARM

Mark Rutland
2017-08-11T17:10:32Z

On Fri, Aug 11, 2017 at 12:51:12PM -0400, Vince Weaver wrote:
> On Fri, 11 Aug 2017, Mark Rutland wrote:
> > Just to check, how does x86 behave on each of those kernel releases?
> >
> > Many things have changed since v4.4.
>
> I'm fairly sure this test (well, the equivelent code in
> tests/record_sample/record_mmap that I based the test on) has been passing
> on all of my x86 test machines since ~3.10 or so, or else I would noticed.

Ok.

> If I can get a custom kernel to boot on one of my machines I can start
> digging in and see if I can find where the EINVAL comes from.

>From a quick scan, I can't spot anything obvious that would affect the
arm64 perf mmap behaviour, that has changed since v4.9.

> This isn't some key thing that needs to be fixed, I was just curious about
> the behavior difference between x86 and ARM.

Sure; likewise I'm curious.

Thanks,
Mark.