With -intel 2.6.3 performance was very bad when using a non gem enabled kernel (2.6.27) and EXA. For example sauerbraten ran with 4 fps and screensaver GLBlur with 1 fps. With -intel 2.6.1 performance was good using the same kernel. Git bisecting led me to commit f1ed73c1ef3e3daa9f695194dcc813167cbcb53d (in 2.6 branch) "Make i830_allocate_memory take tiling parameters" as first bad commit. Using gdb I found tiling was set exactly the same in 2.6.3 as in 2.6.1, so that was good (TILE_XMAJOR for front, back and depth buffers). Looking further I found the line mem->tiling = TILE_NONE; (line 961 in src/i830_memory.c) at the end of i830_allocate_memory suspicious, as mem->tiling now already gets set via i830_allocate_aperture and some buffers do have tiling. Removing that line indeed fixed the performance issue. Now sauerbraten runs with 30+ fps and GLBlur runs smoothly. diff against git master: diff --git a/src/i830_memory.c b/src/i830_memory.c index 052d906..e3314c5 100644 --- a/src/i830_memory.c +++ b/src/i830_memory.c @@ -958,8 +958,6 @@ i830_allocate_memory(ScrnInfoPtr pScrn, const char *name, } } - mem->tiling = TILE_NONE; - return mem; }
commit e964d4e53af3a47de6d09c884be1cc0044d03bea Author: Albert Damen <albrt@gmx.net> Date: Mon Mar 30 11:38:02 2009 -0700 Non-GEM allocations incorrectly force TILE_NONE (bug 20797)
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