[Intel-gfx] [PATCH] drm/i915: Disable THP until we have a GPU read BW W/A

[Joonas Lahtinen]

On Mon, 2017-11-27 at 13:36 +0000, Rantala, Valtteri wrote:
> > -----Original Message-----
> > From: Joonas Lahtinen [mailto:joonas.lahtinen at linux.intel.com]
> > Sent: Monday, November 27, 2017 11:13 AM
> > To: Intel graphics driver community testing & development <intel-
> > gfx at lists.freedesktop.org>
> > Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>; Auld, Matthew
> > <matthew.auld at intel.com>; Chris Wilson <chris at chris-wilson.co.uk>; Jani
> > Nikula <jani.nikula at linux.intel.com>; Vivi, Rodrigo <rodrigo.vivi at intel.com>;
> > Rantala, Valtteri <valtteri.rantala at intel.com>; Tamminen, Eero T
> > <eero.t.tamminen at intel.com>
> > Subject: [PATCH] drm/i915: Disable THP until we have a GPU read BW W/A
> > 
> > We seem to be missing some W/A for 2M pages and are getting a hit on raw
> > GPU read bandwidths (even 30%) even though the GPU write bandwidths
> > improve (even 10%).
> > 
> > For now, disable THP, which is our only practical source of 2M pages until we
> > have a W/A for the issue.
> > 
> > v2:
> > - Be explicit that we talk about GPU bandwidths (Eero)
> > - s/deny/never/ because that's why (Chris)
> > 
> > Reported-by: Valtteri Rantala <valtteri.rantala at intel.com>
> > Fixes: b901bb89324a ("drm/i915/gemfs: enable THP")
> > Signed-off-by: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > Cc: Matthew Auld <matthew.auld at intel.com>
> > Cc: Chris Wilson <chris at chris-wilson.co.uk>
> > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> > Cc: Valtteri Rantala <valtteri.rantala at intel.com>
> > Cc: Eero Tamminen <eero.t.tamminen at intel.com>
> > Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> > Reviewed-by: Matthew Auld <matthew.auld at intel.com>
> 
> Tested-by: Valtteri Rantala <valtteri.rantala at intel.com>

I'm merging the patch, thanks for the report, reviews and testing!

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation