lkml.org 
[lkml]   [2023]   [Jan]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
SubjectRe: [PATCH 0/4] perf intel-pt: Fix the pipe mode (v1)
Hi James,

On Fri, Jan 27, 2023 at 6:42 AM James Clark <james.clark@arm.com> wrote:
>
>
>
> On 27/01/2023 07:22, Adrian Hunter wrote:
> > On 27/01/23 02:19, Namhyung Kim wrote:
> >> Hello,
> >>
> >> I found some problems in Intel-PT and auxtrace in general with pipe.
> >> In the past it used to work with pipe, but recent code fails.
> >
> > Pipe mode is a problem for Intel PT and possibly other auxtrace users.
>
> Just some info from my side: For Arm Coresight we ended up deprecating
> pipe mode, then not supporting it altogether. First was when we added an
> optional step to peek through all of the data to help with an edge case.
> Then we added a requirement to receive a HW_ID packet before decoding
> which necessitated the peek. You can't peek in pipe mode because you
> need to be able to seek, so it's not supported at all anymore.
>
> For Arm SPE I never tested it with piped data. I suppose I could add a
> test at some point, but I don't really see the usecase.

Yeah, it'd be great if we can have a test for Arm SPE.

Anyway, my work env (Google) requires the pipe mode due to the
restriction in disk usage. Without the pipe support, it's not possible
to run `perf record` in production.

Thanks,
Namhyung

\
 
 \ /
  Last update: 2023-03-27 00:00    [W:0.151 / U:2.744 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site