From cd17a717f9f49cffb40fbdef59d1dfac1f9e0cfd Mon Sep 17 00:00:00 2001 From: Dmitriy Vyukov Date: Tue, 29 Jul 2014 11:01:02 +0400 Subject: runtime: simpler and faster GC Implement the design described in: https://docs.google.com/document/d/1v4Oqa0WwHunqlb8C3ObL_uNQw3DfSY-ztoA-4wWbKcg/pub Summary of the changes: GC uses "2-bits per word" pointer type info embed directly into bitmap. Scanning of stacks/data/heap is unified. The old spans types go away. Compiler generates "sparse" 4-bits type info for GC (directly for GC bitmap). Linker generates "dense" 2-bits type info for data/bss (the same as stacks use). Summary of results: -1680 lines of code total (-1000+ in mgc0.c only) -25% memory consumption -3-7% binary size -15% GC pause reduction -7% run time reduction LGTM=khr R=golang-codereviews, rsc, christoph, khr CC=golang-codereviews, rlh https://golang.org/cl/106260045 --- src/pkg/runtime/malloc_test.go | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'src/pkg/runtime/malloc_test.go') diff --git a/src/pkg/runtime/malloc_test.go b/src/pkg/runtime/malloc_test.go index ce2456296a..252760a07e 100644 --- a/src/pkg/runtime/malloc_test.go +++ b/src/pkg/runtime/malloc_test.go @@ -68,6 +68,19 @@ func BenchmarkMallocTypeInfo16(b *testing.B) { mallocSink = x } +type LargeStruct struct { + x [16][]byte +} + +func BenchmarkMallocLargeStruct(b *testing.B) { + var x uintptr + for i := 0; i < b.N; i++ { + p := make([]LargeStruct, 2) + x ^= uintptr(unsafe.Pointer(&p[0])) + } + mallocSink = x +} + var n = flag.Int("n", 1000, "number of goroutines") func BenchmarkGoroutineSelect(b *testing.B) { -- cgit v1.3-5-g9baa