Mercurial > hg > truffle
changeset 17760:5479cb006184
8036860: Pad and cache-align the BiasedMappedArray
Summary: Pad and cache-align BiasedMappedArray instances by default to avoid performance variability problems due to false sharing, as instances of this data structures are typically used for performance sensitive code.
Reviewed-by: brutisso, stefank
| author | tschatzl |
|---|---|
| date | Mon, 24 Mar 2014 15:31:00 +0100 |
| parents | bc22cbb8b45a |
| children | ac767c227ea2 |
| files | src/share/vm/gc_implementation/g1/g1BiasedArray.cpp src/share/vm/gc_implementation/g1/g1BiasedArray.hpp src/share/vm/memory/padded.hpp src/share/vm/memory/padded.inline.hpp |
| diffstat | 4 files changed, 28 insertions(+), 6 deletions(-) [+] |
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--- a/src/share/vm/gc_implementation/g1/g1BiasedArray.cpp Mon Mar 24 15:30:56 2014 +0100 +++ b/src/share/vm/gc_implementation/g1/g1BiasedArray.cpp Mon Mar 24 15:31:00 2014 +0100 @@ -24,6 +24,14 @@ #include "precompiled.hpp" #include "gc_implementation/g1/g1BiasedArray.hpp" +#include "memory/padded.inline.hpp" + +// Allocate a new array, generic version. +address G1BiasedMappedArrayBase::create_new_base_array(size_t length, size_t elem_size) { + assert(length > 0, "just checking"); + assert(elem_size > 0, "just checking"); + return PaddedPrimitiveArray<u_char, mtGC>::create_unfreeable(length * elem_size); +} #ifndef PRODUCT void G1BiasedMappedArrayBase::verify_index(idx_t index) const {
--- a/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp Mon Mar 24 15:30:56 2014 +0100 +++ b/src/share/vm/gc_implementation/g1/g1BiasedArray.hpp Mon Mar 24 15:31:00 2014 +0100 @@ -25,8 +25,8 @@ #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_G1BIASEDARRAY_HPP +#include "memory/allocation.hpp" #include "utilities/debug.hpp" -#include "memory/allocation.inline.hpp" // Implements the common base functionality for arrays that contain provisions // for accessing its elements using a biased index. @@ -48,11 +48,7 @@ _bias(0), _shift_by(0) { } // Allocate a new array, generic version. - static address create_new_base_array(size_t length, size_t elem_size) { - assert(length > 0, "just checking"); - assert(elem_size > 0, "just checking"); - return NEW_C_HEAP_ARRAY(u_char, length * elem_size, mtGC); - } + static address create_new_base_array(size_t length, size_t elem_size); // Initialize the members of this class. The biased start address of this array // is the bias (in elements) multiplied by the element size.
--- a/src/share/vm/memory/padded.hpp Mon Mar 24 15:30:56 2014 +0100 +++ b/src/share/vm/memory/padded.hpp Mon Mar 24 15:31:00 2014 +0100 @@ -101,4 +101,12 @@ static T** create_unfreeable(uint rows, uint columns, size_t* allocation_size = NULL); }; +// Helper class to create an array of T objects. The array as a whole will +// start at a multiple of alignment and its size will be aligned to alignment. +template <class T, MEMFLAGS flags, size_t alignment = DEFAULT_CACHE_LINE_SIZE> +class PaddedPrimitiveArray { + public: + static T* create_unfreeable(size_t length); +}; + #endif // SHARE_VM_MEMORY_PADDED_HPP
--- a/src/share/vm/memory/padded.inline.hpp Mon Mar 24 15:30:56 2014 +0100 +++ b/src/share/vm/memory/padded.inline.hpp Mon Mar 24 15:31:00 2014 +0100 @@ -76,3 +76,13 @@ return result; } + +template <class T, MEMFLAGS flags, size_t alignment> +T* PaddedPrimitiveArray<T, flags, alignment>::create_unfreeable(size_t length) { + // Allocate a chunk of memory large enough to allow for some alignment. + void* chunk = AllocateHeap(length * sizeof(T) + alignment, flags); + + memset(chunk, 0, length * sizeof(T) + alignment); + + return (T*)align_pointer_up(chunk, alignment); +}