From: "Dixit, Ashutosh" <ashutosh.dixit@intel.com>
To: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [Intel-gfx] [PATCH] drm/i915/perf: Do not clear pollin for small user read buffers
Date: Wed, 25 Mar 2020 13:44:50 -0700 [thread overview]
Message-ID: <87a744tb99.wl-ashutosh.dixit@intel.com> (raw)
In-Reply-To: <37f21906-12dd-efbf-6e49-64bd19bf5e23@intel.com>
On Wed, 25 Mar 2020 12:25:59 -0700, Lionel Landwerlin wrote:
>
> On 25/03/2020 20:20, Ashutosh Dixit wrote:
> > It is wrong to block the user thread in the next poll when OA data is
> > already available which could not fit in the user buffer provided in
> > the previous read. In several cases the exact user buffer size is not
> > known. Blocking user space in poll can lead to data loss when the
> > buffer size used is smaller than the available data.
> >
> > This change fixes this issue and allows user space to read all OA data
> > even when using a buffer size smaller than the available data using
> > multiple non-blocking reads rather than staying blocked in poll till
> > the next timer interrupt.
>
> Looks like you found a pretty important issue.
>
> Can you write an IGT test case so that we don't run into it again?
OK I'll see if I can come up with an IGT.
Thanks!
--
Ashutosh
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next prev parent reply other threads:[~2020-03-25 20:44 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-25 18:20 [Intel-gfx] [PATCH] drm/i915/perf: Do not clear pollin for small user read buffers Ashutosh Dixit
2020-03-25 19:25 ` Lionel Landwerlin
2020-03-25 20:44 ` Dixit, Ashutosh [this message]
2020-03-25 19:33 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2020-03-26 0:26 ` [Intel-gfx] ✓ Fi.CI.IGT: " Patchwork
2020-03-26 0:32 ` [Intel-gfx] [PATCH] " Umesh Nerlige Ramappa
2020-03-26 1:52 ` Dixit, Ashutosh
2020-03-26 18:02 ` Umesh Nerlige Ramappa
2020-03-27 1:28 ` Dixit, Ashutosh
2020-03-26 4:43 Ashutosh Dixit
2020-03-26 9:09 ` Lionel Landwerlin
2020-03-27 3:39 ` Dixit, Ashutosh
2020-03-27 23:11 Ashutosh Dixit
2020-03-27 23:16 Ashutosh Dixit
2020-03-30 8:23 ` Lionel Landwerlin
2020-03-31 5:47 ` Dixit, Ashutosh
2020-03-31 5:22 Ashutosh Dixit
2020-03-31 7:34 ` Lionel Landwerlin
2020-03-31 23:29 ` Dixit, Ashutosh
2020-03-31 23:14 Ashutosh Dixit
2020-04-01 6:57 ` Lionel Landwerlin
2020-04-01 7:43 ` Dixit, Ashutosh
2020-04-01 7:51 ` Lionel Landwerlin
2020-04-03 1:01 Ashutosh Dixit
2020-04-03 16:17 ` Chris Wilson
2020-04-03 17:45 ` Dixit, Ashutosh
2020-04-03 17:59 ` Chris Wilson
2020-04-08 23:42 Ashutosh Dixit
2020-04-13 22:05 ` Rodrigo Vivi
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