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

* [PATCH] drm/i915: Disable THP until we have a read BW W/A
@ 2017-11-24 11:27 Joonas Lahtinen
  2017-11-24 12:12 ` Chris Wilson
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Joonas Lahtinen @ 2017-11-24 11:27 UTC (permalink / raw)
  To: Intel graphics driver community testing & development
  Cc: Eero Tamminen, Matthew Auld, Rodrigo Vivi

We seem to be missing some W/A for 2M pages and are getting
a hit on raw read bandwidths (even 30%) even though the 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.

Reported-by: Valtteri Rantala <valtteri.rantala@intel.com>
Fixes: b901bb89324a ("drm/i915/gemfs: enable THP")
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Valtteri Rantala <valtteri.rantala@intel.com>
Cc: Eero Tamminen <eero.t.tamminen@intel.com>
---
 drivers/gpu/drm/i915/i915_gemfs.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/i915_gemfs.c b/drivers/gpu/drm/i915/i915_gemfs.c
index e2993857df37..851d827d83a8 100644
--- a/drivers/gpu/drm/i915/i915_gemfs.c
+++ b/drivers/gpu/drm/i915/i915_gemfs.c
@@ -52,7 +52,8 @@ int i915_gemfs_init(struct drm_i915_private *i915)
 
 	if (has_transparent_hugepage()) {
 		struct super_block *sb = gemfs->mnt_sb;
-		char options[] = "huge=within_size";
+		/* FIXME: Disabled until we get W/A for read BW issue. */
+		char options[] = "huge=deny";
 		int flags = 0;
 		int err;
 
-- 
2.13.6

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