igl | vulkan | Reuse the cached VkDescriptorSet to reduce vkAllocateDescriptorSets(). #336
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corporateshark
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corporateshark
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Please post your benchmarking results with and without this approach.
src/igl/vulkan/VulkanContext.cpp
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| VkDevice device_ = VK_NULL_HANDLE; | ||
| VkDescriptorPool pool_ = VK_NULL_HANDLE; | ||
| uint32_t dsetCursor_ = 0; | ||
| std::vector<VkDescriptorSet> allocedDSet_; |
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How about a hash table descriptor set content → VkDescriptorSet?
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I'm still thinking about it.
src/igl/vulkan/VulkanContext.cpp
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| VkDescriptorPool pool_ = VK_NULL_HANDLE; | ||
| uint32_t dsetCursor_ = 0; | ||
| std::vector<VkDescriptorSet> allocedDSet_; | ||
| bool isNewPool_ = true; //is a new created pool or an old cached pool |
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Is there a way to cache descriptors from old pools?
Also, a space after // is missing.
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I add a new filed allocatedDSet in ExtinctDescriptorPool to cache descriptors from old pools.
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before: after:
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This looks very promising. Any numeric perf improvement values you've got? I'll test it on my side as well. |
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@corporateshark has imported this pull request. If you are a Meta employee, you can view this in D90555194. |
| VK_ASSERT(ivkAllocateDescriptorSet(&ctx_.vf_, device_, pool_, dsl_, &dset)); | ||
| allocatedDSet_.emplace_back(dset); | ||
| } else { | ||
| dset = allocatedDSet_[dsetCursor_++]; |
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Potential out-of-bounds access when reusing a descriptor pool. When a pool is reused (line 277), allocatedDSet_ is restored from the extinct pool, but numRemainingDSetsInPool_ is always reset to kNumDSetsPerPool (64) at line 266. If the pool was previously switched before all 64 descriptor sets were allocated, allocatedDSet_ will have fewer than 64 elements. Subsequent calls to getNextDescriptorSet() could then access allocatedDSet_[dsetCursor_++] at line 257 beyond the vector's bounds. Consider either: (1) setting numRemainingDSetsInPool_ based on the actual size of the restored allocatedDSet_ vector, or (2) ensuring that pools always have exactly kNumDSetsPerPool descriptor sets allocated before being marked as extinct.
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