Commit 2eec53d0 authored by Chris Wilson's avatar Chris Wilson

uxa: Default to using TILING_X for pixmaps.

On memory constrained hardware, tiling is vital for good performance as
it minimizes cache misses.  The downside is that for older hardware
(which often suffers from the lack of bandwidth) requires the use of
fences for many operations, which are in short supply and so may cause
shorter batchbuffers. However our batch buffers are typically short and
so this is unlikely to be a concern and not affect the performance wins.

A quick bit of testing suggests the effect is inconclusive on
                  linear            tiled
  xcb             205.470           206.219
  xcb-render-0.0  404.704           388.413
  xlib            166.410           170.805

A secondary effect of the patch is to workaround a G31 specific hang
when attempting to use linear 2048x2048 surfaces. Bonus!

  Bug 25375 - Performance issue using texture from pixmap (tfp) glx extension on 945

  Bug 27100 - GPU Hung copying a 2048x1152 pixmap Chris Wilson's avatarChris Wilson <>
Tested-by: default avatarJohn <>
parent 9c037f61
......@@ -135,8 +135,20 @@ i830_uxa_pixmap_compute_size(PixmapPtr pixmap,
pitch_align = intel->accel_pixmap_pitch_alignment;
size = ROUND_TO((w * pixmap->drawable.bitsPerPixel + 7) / 8,
pitch_align) * ALIGN (h, 2);
if (size < 4096)
if (!IS_I965G(intel)) {
/* Older hardware requires fences to be pot size
* aligned with a minimum of 1 MiB, so causes
* massive overallocation for small textures.
if (size < 1024*1024/2)
*tiling = I915_TILING_NONE;
} else if (size <= 4096) {
/* Disable tiling beneath a page size, we will not see
* any benefit from reducing TLB misses and instead
* just incur extra cost when we require a fence.
*tiling = I915_TILING_NONE;
......@@ -863,11 +875,14 @@ i830_uxa_create_pixmap(ScreenPtr screen, int w, int h, int depth,
return NullPixmap;
priv->tiling = I915_TILING_X;
/* Always attempt to tile, compute_size() will remove the
* tiling for pixmaps that are either too large or too small
* to be effectively tiled.
priv->tiling = I915_TILING_X;
priv->tiling = I915_TILING_Y;
priv->tiling = I915_TILING_NONE;
size = i830_uxa_pixmap_compute_size(pixmap, w, h,
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