• Kenneth Graunke's avatar
    isl: Enable Tigerlake HDC:L1 caches via MOCS in various cases. · aca31baa
    Kenneth Graunke authored
    
    
    Thanks to Felix Degrood for discovering that we missed enabling this
    additional caching on Tigerlake!  Felix also benchmarked the changes.
    
    We now use MOCS 48 (HDC:L1 + L3 + LLC) for render targets, textures,
    and pull constant buffers.  We leave storage buffers & images, as well
    as stateless messages, using the previous MOCS 2 value.  We can't use
    HDC:L1 with atomics, and we don't know a priori whether storage buffers
    will be used with atomics or not.  Similarly, the Vulkan buffer device
    address feature allows atomics to be performed on buffers via stateless
    messages, and we only can control MOCS at the base address level, so
    we can't do much there.
    
    This is closer to what the Windows Vulkan and OpenGL drivers do,
    though it isn't quite the same - they also disable LLC in some cases,
    but we observed this to have noticable performance regressions when
    we tried (though a couple titles benefited).  We may try experiment
    with that in the future.
    
    Improves performance in a number of titles:
    
    - Unreal Engine 4 Shooter Demo   [VK]: 11.8%
    - Witcher 3                    [DXVK]:  3.9%
    - Rise of the Tomb Raider        [VK]:  1.5%
    - Shadow of the Tomb Raider      [VK]:  1.0%
    - Grand Theft Auto V           [DXVK]:  0.8%
    
    We did not observe any performance regressions.
    Reviewed-by: Jason Ekstrand's avatarJason Ekstrand <jason@jlekstrand.net>
    Part-of: <!7104>
    aca31baa
isl.h 86.6 KB