Re: [PATCH v10 2/2] drm/i915: Allow user to set cache at BO creation

From: Jordan Justen <jordan.l.justen@intel.com>
To: Andi Shyti <andi.shyti@linux.intel.com>, fei.yang@intel.com
Cc: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	Chris Wilson <chris.p.wilson@linux.intel.com>,
	intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org,
	Andi Shyti <andi.shyti@linux.intel.com>,
	rohan.garg@intel.com, Matt Roper <matthew.d.roper@intel.com>
Subject: Re: [PATCH v10 2/2] drm/i915: Allow user to set cache at BO creation
Date: Mon, 22 May 2023 08:25:33 -0700	[thread overview]
Message-ID: <168476913389.1509813.15102550159463496187@jljusten-skl> (raw)
In-Reply-To: <ZGtXmBh42oLIxcyi@ashyti-mobl2.lan>

On 2023-05-22 04:52:56, Andi Shyti wrote:
> Hi,
> 
> On Thu, May 18, 2023 at 10:11:03PM -0700, fei.yang@intel.com wrote:
> > From: Fei Yang <fei.yang@intel.com>
> > 
> > To comply with the design that buffer objects shall have immutable
> > cache setting through out their life cycle, {set, get}_caching ioctl's
> > are no longer supported from MTL onward. With that change caching
> > policy can only be set at object creation time. The current code
> > applies a default (platform dependent) cache setting for all objects.
> > However this is not optimal for performance tuning. The patch extends
> > the existing gem_create uAPI to let user set PAT index for the object
> > at creation time.
> > The new extension is platform independent, so UMD's can switch to using
> > this extension for older platforms as well, while {set, get}_caching are
> > still supported on these legacy paltforms for compatibility reason.
> > 
> > Test igt@gem_create@create_ext_set_pat posted at
> > https://patchwork.freedesktop.org/series/117695/
> > 
> > Tested with https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22878
> > 
> > Signed-off-by: Fei Yang <fei.yang@intel.com>
> > Cc: Chris Wilson <chris.p.wilson@linux.intel.com>
> > Cc: Matt Roper <matthew.d.roper@intel.com>
> > Cc: Andi Shyti <andi.shyti@linux.intel.com>
> > Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com>
> > Acked-by: Jordan Justen <jordan.l.justen@intel.com>
> > Tested-by: Jordan Justen <jordan.l.justen@intel.com>
> 
> last call for comments and reviews on this patch. If nothing
> comes I am going to push it tomorrow morning (Europe).
> 
> There is also a merge request from Mesa pending on this so that I
> don't want to keep it hanging any longer.

No need to wait any longer with regard to feedback from Mesa.

I definitely was hoping for more consideration of the userspace
request, but it's been decisively rejected. My ack was not readily
given, but it stands.

-Jordan