Plan: BO move throttling for visible VRAM evictions

[Michel Dänzer]

On 28/03/17 12:50 PM, zhoucm1 wrote:
> On 2017年03月28日 10:40, Michel Dänzer wrote:
>> On 27/03/17 04:53 PM, Zhou, David(ChunMing) wrote:
>>> For APU special case, can we prevent eviction happening between VRAM
>>> <----> GTT?
>> We can, if we can close the performance gap between VRAM and GTT. We
>> measured around 30% gap a while ago, though right now I'm only measuring
>> ~5%, but the test system has slower RAM now (still dual channel though).
> My impression VRAM and GTT have no much difference for APU case, if I'm
> wrong, pls correct me.

The Mesa patch below makes radeonsi use mostly GTT instead of mostly
VRAM, and slows down Unigine Valley by about 5% on my desktop Kaveri.
You can try it for yourself.


diff --git a/src/gallium/drivers/radeon/r600_buffer_common.c b/src/gallium/drivers/radeon/r600_buffer_common.c
index da6f0206d7..47661cab76 100644
--- a/src/gallium/drivers/radeon/r600_buffer_common.c
+++ b/src/gallium/drivers/radeon/r600_buffer_common.c
@@ -175,9 +175,11 @@ void r600_init_resource_fields(struct r600_common_screen *rscreen,
         * placements even with a low amount of stolen VRAM.
         */
        if (!rscreen->info.has_dedicated_vram &&
-           (rscreen->info.drm_major < 3 || rscreen->info.drm_minor < 6) &&
-           res->domains == RADEON_DOMAIN_VRAM)
-               res->domains = RADEON_DOMAIN_VRAM_GTT;
+           res->domains == RADEON_DOMAIN_VRAM &&
+           !(res->b.b.bind & PIPE_BIND_SCANOUT)) {
+          res->domains = RADEON_DOMAIN_GTT;
+          res->flags |= RADEON_FLAG_GTT_WC;
+       }

        if (rscreen->debug_flags & DBG_NO_WC)
                res->flags &= ~RADEON_FLAG_GTT_WC;



-- 
Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer