Vulkan: Update dynamic buffer size policy
When allocating a dynamic buffer, it is checked if the new data can
fit in an existing allocation. However, if the size of the new data
exceeds that of the current buffer, a new one is allocated. To avoid
using too much memory, if the data size is less than a threshold (a
fraction of the current buffer size, a smaller size will be used for
the new buffer.
However, with a specific pattern for the new sizes, combined with the
threshold value, there could be many allocations and deallocations,
which can affect the performance.
In this CL, the policy to update the dynamic buffer size is updated to
avoid this issue.
* Instead of using a smaller buffer when the required size is less than
1/4 of the current buffer size, it is done when the average required
size is less than 1/8 of the current size.
* Added a decaying average required size for the DynamicBuffer object.
* mSizeInRecentHistory
* For each new buffer allocation, the new required size is used with
the average size to calculate the new average.
* For each calculation, kDecayCoeffPercent is used as the weight for
the existing average, and the rest is the new required size, plus
rounding.
* kDecayCoeffPercent is currently set to 20%.
* sizeIgnoringHistory renamed to minRequiredBlockSize for more clarity.
Bug: b/322216767
Change-Id: Idcabbbe50f656910fe2103925e4d6d8602ca3425
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/5254218
Commit-Queue: Amirali Abdolrashidi <abdolrashidi@google.com>
Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>
Reviewed-by: Charlie Lao <cclao@google.com>
diff --git a/src/libANGLE/renderer/vulkan/vk_helpers.cpp b/src/libANGLE/renderer/vulkan/vk_helpers.cpp
index 586632e..9892ad7 100644
--- a/src/libANGLE/renderer/vulkan/vk_helpers.cpp
+++ b/src/libANGLE/renderer/vulkan/vk_helpers.cpp
@@ -2974,6 +2974,7 @@
mInitialSize(0),
mNextAllocationOffset(0),
mSize(0),
+ mSizeInRecentHistory(0),
mAlignment(0),
mMemoryPropertyFlags(0)
{}
@@ -2985,6 +2986,7 @@
mBuffer(std::move(other.mBuffer)),
mNextAllocationOffset(other.mNextAllocationOffset),
mSize(other.mSize),
+ mSizeInRecentHistory(other.mSizeInRecentHistory),
mAlignment(other.mAlignment),
mMemoryPropertyFlags(other.mMemoryPropertyFlags),
mInFlightBuffers(std::move(other.mInFlightBuffers)),
@@ -3010,8 +3012,9 @@
// Check that we haven't overridden the initial size of the buffer in setMinimumSizeForTesting.
if (mInitialSize == 0)
{
- mInitialSize = initialSize;
- mSize = 0;
+ mInitialSize = initialSize;
+ mSize = 0;
+ mSizeInRecentHistory = initialSize;
}
// Workaround for the mock ICD not supporting allocations greater than 0x1000.
@@ -3104,10 +3107,19 @@
RendererVk *renderer = context->getRenderer();
- const size_t sizeIgnoringHistory = std::max(mInitialSize, sizeToAllocate);
- if (sizeToAllocate > mSize || sizeIgnoringHistory < mSize / 4)
+ const size_t minRequiredBlockSize = std::max(mInitialSize, sizeToAllocate);
+
+ // The average required buffer size in recent history is used to determine whether the currently
+ // used buffer size needs to be reduced (when it goes below 1/8 of the current buffer size).
+ constexpr uint32_t kDecayCoeffPercent = 20;
+ static_assert(kDecayCoeffPercent >= 0 && kDecayCoeffPercent <= 100);
+ mSizeInRecentHistory = (mSizeInRecentHistory * kDecayCoeffPercent +
+ minRequiredBlockSize * (100 - kDecayCoeffPercent) + 50) /
+ 100;
+
+ if (sizeToAllocate > mSize || mSizeInRecentHistory < mSize / 8)
{
- mSize = sizeIgnoringHistory;
+ mSize = minRequiredBlockSize;
// Clear the free list since the free buffers are now either too small or too big.
ReleaseBufferListToRenderer(renderer, &mBufferFreeList);
}
@@ -3240,12 +3252,14 @@
mInitialSize = minSize;
// Forces a new allocation on the next allocate.
- mSize = 0;
+ mSize = 0;
+ mSizeInRecentHistory = 0;
}
void DynamicBuffer::reset()
{
mSize = 0;
+ mSizeInRecentHistory = 0;
mNextAllocationOffset = 0;
}
diff --git a/src/libANGLE/renderer/vulkan/vk_helpers.h b/src/libANGLE/renderer/vulkan/vk_helpers.h
index 7e029f4..03b5e38 100644
--- a/src/libANGLE/renderer/vulkan/vk_helpers.h
+++ b/src/libANGLE/renderer/vulkan/vk_helpers.h
@@ -132,6 +132,7 @@
std::unique_ptr<BufferHelper> mBuffer;
uint32_t mNextAllocationOffset;
size_t mSize;
+ size_t mSizeInRecentHistory;
size_t mAlignment;
VkMemoryPropertyFlags mMemoryPropertyFlags;
