On Mon, 3 Jun 2019 at 11:57, Koenig, Christian <[email protected]> wrote:
> Am 02.06.19 um 12:32 schrieb Alex Smith: > > Put the uncached GTT type at a higher index than the visible VRAM type, > > rather than having GTT first. > > > > When we don't have dedicated VRAM, we don't have a non-visible VRAM > > type, and the property flags for GTT and visible VRAM are identical. > > According to the spec, for types with identical flags, we should give > > the one with better performance a lower index. > > > > Previously, apps which follow the spec guidance for choosing a memory > > type would have picked the GTT type in preference to visible VRAM (all > > Feral games will do this), and end up with lower performance. > > > > On a Ryzen 5 2500U laptop (Raven Ridge), this improves average FPS in > > the Rise of the Tomb Raider benchmark by up to ~30%. Tested a couple of > > other (Feral) games and saw similar improvement on those as well. > > Well that patch doesn't looks like a good idea to me. > > Using VRAM over uncached GTT should have something between no and only > minimal performance difference on APU. > > To make things even worse VRAM is still needed for scanout and newer > laptops have only a very very low default setting (32 or 16MB). So you > can end up in VRAM clashing on those systems. > > Can you check some kernel statistics to figure out what exactly is going > on here? > What statistics should I look at? Thanks, Alex > > Regards, > Christian. > > > > > Signed-off-by: Alex Smith <[email protected]> > > --- > > I noticed that the memory types advertised on my Raven laptop looked a > > bit odd so played around with it and found this. I'm not sure if it is > > actually expected that the performance difference between visible VRAM > > and GTT is so large, seeing as it's not dedicated VRAM, but the results > > are clear (and consistent, tested multiple times). > > --- > > src/amd/vulkan/radv_device.c | 18 +++++++++++++++--- > > 1 file changed, 15 insertions(+), 3 deletions(-) > > > > diff --git a/src/amd/vulkan/radv_device.c b/src/amd/vulkan/radv_device.c > > index 3cf050ed220..d36ee226ebd 100644 > > --- a/src/amd/vulkan/radv_device.c > > +++ b/src/amd/vulkan/radv_device.c > > @@ -171,12 +171,11 @@ radv_physical_device_init_mem_types(struct > radv_physical_device *device) > > .heapIndex = vram_index, > > }; > > } > > - if (gart_index >= 0) { > > + if (gart_index >= 0 && device->rad_info.has_dedicated_vram) { > > device->mem_type_indices[type_count] = > RADV_MEM_TYPE_GTT_WRITE_COMBINE; > > device->memory_properties.memoryTypes[type_count++] = > (VkMemoryType) { > > .propertyFlags = > VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | > > - VK_MEMORY_PROPERTY_HOST_COHERENT_BIT | > > - (device->rad_info.has_dedicated_vram ? 0 : > VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT), > > + VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, > > .heapIndex = gart_index, > > }; > > } > > @@ -189,6 +188,19 @@ radv_physical_device_init_mem_types(struct > radv_physical_device *device) > > .heapIndex = visible_vram_index, > > }; > > } > > + if (gart_index >= 0 && !device->rad_info.has_dedicated_vram) { > > + /* Put GTT after visible VRAM for GPUs without dedicated > VRAM > > + * as they have identical property flags, and according to > the > > + * spec, for types with identical flags, the one with > greater > > + * performance must be given a lower index. */ > > + device->mem_type_indices[type_count] = > RADV_MEM_TYPE_GTT_WRITE_COMBINE; > > + device->memory_properties.memoryTypes[type_count++] = > (VkMemoryType) { > > + .propertyFlags = > VK_MEMORY_PROPERTY_DEVICE_LOCAL_BIT | > > + VK_MEMORY_PROPERTY_HOST_VISIBLE_BIT | > > + VK_MEMORY_PROPERTY_HOST_COHERENT_BIT, > > + .heapIndex = gart_index, > > + }; > > + } > > if (gart_index >= 0) { > > device->mem_type_indices[type_count] = > RADV_MEM_TYPE_GTT_CACHED; > > device->memory_properties.memoryTypes[type_count++] = > (VkMemoryType) { > >
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