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Diffstat (limited to '')
-rw-r--r-- | third_party/jpeg-xl/lib/jxl/base/cache_aligned.h | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/third_party/jpeg-xl/lib/jxl/base/cache_aligned.h b/third_party/jpeg-xl/lib/jxl/base/cache_aligned.h new file mode 100644 index 0000000000..e57df14837 --- /dev/null +++ b/third_party/jpeg-xl/lib/jxl/base/cache_aligned.h @@ -0,0 +1,74 @@ +// Copyright (c) the JPEG XL Project Authors. All rights reserved. +// +// Use of this source code is governed by a BSD-style +// license that can be found in the LICENSE file. + +#ifndef LIB_JXL_BASE_CACHE_ALIGNED_H_ +#define LIB_JXL_BASE_CACHE_ALIGNED_H_ + +// Memory allocator with support for alignment + misalignment. + +#include <stddef.h> +#include <stdint.h> + +#include <memory> + +#include "lib/jxl/base/compiler_specific.h" + +namespace jxl { + +// Functions that depend on the cache line size. +class CacheAligned { + public: + static void PrintStats(); + + static constexpr size_t kPointerSize = sizeof(void*); + static constexpr size_t kCacheLineSize = 64; + // To avoid RFOs, match L2 fill size (pairs of lines). + static constexpr size_t kAlignment = 2 * kCacheLineSize; + // Minimum multiple for which cache set conflicts and/or loads blocked by + // preceding stores can occur. + static constexpr size_t kAlias = 2048; + + // Returns a 'random' (cyclical) offset suitable for Allocate. + static size_t NextOffset(); + + // Returns null or memory whose address is congruent to `offset` (mod kAlias). + // This reduces cache conflicts and load/store stalls, especially with large + // allocations that would otherwise have similar alignments. At least + // `payload_size` (which can be zero) bytes will be accessible. + static void* Allocate(size_t payload_size, size_t offset); + + static void* Allocate(const size_t payload_size) { + return Allocate(payload_size, NextOffset()); + } + + static void Free(const void* aligned_pointer); +}; + +// Avoids the need for a function pointer (deleter) in CacheAlignedUniquePtr. +struct CacheAlignedDeleter { + void operator()(uint8_t* aligned_pointer) const { + return CacheAligned::Free(aligned_pointer); + } +}; + +using CacheAlignedUniquePtr = std::unique_ptr<uint8_t[], CacheAlignedDeleter>; + +// Does not invoke constructors. +static inline CacheAlignedUniquePtr AllocateArray(const size_t bytes) { + return CacheAlignedUniquePtr( + static_cast<uint8_t*>(CacheAligned::Allocate(bytes)), + CacheAlignedDeleter()); +} + +static inline CacheAlignedUniquePtr AllocateArray(const size_t bytes, + const size_t offset) { + return CacheAlignedUniquePtr( + static_cast<uint8_t*>(CacheAligned::Allocate(bytes, offset)), + CacheAlignedDeleter()); +} + +} // namespace jxl + +#endif // LIB_JXL_BASE_CACHE_ALIGNED_H_ |