• Chris Wilson's avatar
    agp/intel: Use a write-combining map for updating PTEs · edef7e68
    Chris Wilson authored
    Rewriting the PTE entries using an WC mapping is roughly an order of
    magnitude faster than through the uncached mapping. This makes an
    observable difference on workloads that cycle through large numbers of
    buffers, for example Chromium using ShmPixmaps where virtually all the
    CPU time is currently spent rebinding the userptr.
    
    v2: Limit the WC mapping to older generations as we have observed that
    the TLB invalidation on SandyBridge+ is unreliable with WC updates.
    See i-g-t/tests/gem_gtt_cpu_tlb
    Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
    Signed-off-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
    edef7e68
intel-gtt.c 44.6 KB