From 96dcc4457b9aad418abc0eb4316c21fefdbf08e1 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Martin=20M=C3=B6hrmann?= Date: Fri, 1 Jun 2018 14:30:49 +0200 Subject: [PATCH] runtime: replace typedmemmmove with bulkBarrierPreWrite and memmove in growslice MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit A bulkBarrierPreWrite together with a memmove as used in typedslicecopy is faster than a typedmemmove for each element of the old slice that needs to be copied to the new slice. typedslicecopy is not used here as runtime functions should not call other instrumented runtime functions and some conditions like dst == src or the destination slice not being large enought that are checked for in typedslicecopy can not happen in growslice. Append 13.5ns ± 6% 13.3ns ± 3% ~ (p=0.304 n=10+10) AppendGrowByte 1.18ms ± 2% 1.19ms ± 1% ~ (p=0.113 n=10+9) AppendGrowString 123ms ± 1% 73ms ± 1% -40.39% (p=0.000 n=9+8) AppendSlice/1Bytes 3.81ns ± 1% 3.78ns ± 1% ~ (p=0.116 n=10+10) AppendSlice/4Bytes 3.71ns ± 1% 3.70ns ± 0% ~ (p=0.095 n=10+9) AppendSlice/7Bytes 3.73ns ± 0% 3.75ns ± 1% ~ (p=0.442 n=10+10) AppendSlice/8Bytes 4.00ns ± 1% 4.01ns ± 1% ~ (p=0.330 n=10+10) AppendSlice/15Bytes 4.29ns ± 1% 4.28ns ± 1% ~ (p=0.536 n=10+10) AppendSlice/16Bytes 4.28ns ± 1% 4.31ns ± 1% +0.75% (p=0.019 n=10+10) AppendSlice/32Bytes 4.57ns ± 2% 4.58ns ± 2% ~ (p=0.236 n=10+10) AppendSliceLarge/1024Bytes 305ns ± 2% 306ns ± 1% ~ (p=0.236 n=10+10) AppendSliceLarge/4096Bytes 1.06µs ± 1% 1.06µs ± 0% ~ (p=1.000 n=9+10) AppendSliceLarge/16384Bytes 3.12µs ± 2% 3.11µs ± 1% ~ (p=0.493 n=10+10) AppendSliceLarge/65536Bytes 5.61µs ± 5% 5.36µs ± 2% -4.58% (p=0.003 n=10+8) AppendSliceLarge/262144Bytes 21.0µs ± 1% 19.5µs ± 1% -7.09% (p=0.000 n=8+10) AppendSliceLarge/1048576Bytes 78.4µs ± 1% 78.7µs ± 2% ~ (p=0.315 n=8+10) AppendStr/1Bytes 3.96ns ± 6% 3.99ns ± 9% ~ (p=0.591 n=10+10) AppendStr/4Bytes 3.98ns ± 1% 3.99ns ± 1% ~ (p=0.515 n=9+9) AppendStr/8Bytes 4.27ns ± 1% 4.27ns ± 1% ~ (p=0.633 n=10+10) AppendStr/16Bytes 4.56ns ± 2% 4.55ns ± 1% ~ (p=0.869 n=10+10) AppendStr/32Bytes 4.85ns ± 1% 4.89ns ± 1% +0.71% (p=0.003 n=10+8) AppendSpecialCase 18.7ns ± 1% 18.7ns ± 1% ~ (p=0.144 n=10+10) AppendInPlace/NoGrow/Byte 438ns ± 1% 439ns ± 1% ~ (p=0.135 n=10+8) AppendInPlace/NoGrow/1Ptr 1.05µs ± 2% 1.05µs ± 1% ~ (p=0.469 n=10+10) AppendInPlace/NoGrow/2Ptr 1.77µs ± 1% 1.78µs ± 2% ~ (p=0.469 n=10+10) AppendInPlace/NoGrow/3Ptr 1.94µs ± 1% 1.93µs ± 2% ~ (p=0.517 n=10+10) AppendInPlace/NoGrow/4Ptr 3.18µs ± 1% 3.17µs ± 0% ~ (p=0.483 n=10+9) AppendInPlace/Grow/Byte 382ns ± 2% 383ns ± 2% ~ (p=0.705 n=9+10) AppendInPlace/Grow/1Ptr 383ns ± 1% 384ns ± 1% ~ (p=0.844 n=10+10) AppendInPlace/Grow/2Ptr 459ns ± 2% 467ns ± 2% +1.74% (p=0.001 n=10+10) AppendInPlace/Grow/3Ptr 593ns ± 1% 597ns ± 2% ~ (p=0.195 n=10+10) AppendInPlace/Grow/4Ptr 583ns ± 2% 589ns ± 2% ~ (p=0.084 n=10+10) Change-Id: I629872f065a22b29267c1adbfc578aaedd36d365 Reviewed-on: https://go-review.googlesource.com/115755 Run-TryBot: Martin Möhrmann TryBot-Result: Gobot Gobot Reviewed-by: Keith Randall --- src/runtime/mbarrier.go | 2 -- src/runtime/slice.go | 10 +++------- 2 files changed, 3 insertions(+), 9 deletions(-) diff --git a/src/runtime/mbarrier.go b/src/runtime/mbarrier.go index b6c5ee0658..5142f4327a 100644 --- a/src/runtime/mbarrier.go +++ b/src/runtime/mbarrier.go @@ -226,8 +226,6 @@ func reflectcallmove(typ *_type, dst, src unsafe.Pointer, size uintptr) { //go:nosplit func typedslicecopy(typ *_type, dst, src slice) int { - // TODO(rsc): If typedslicecopy becomes faster than calling - // typedmemmove repeatedly, consider using during func growslice. n := dst.len if n > src.len { n = src.len diff --git a/src/runtime/slice.go b/src/runtime/slice.go index fd5d08b52c..737aab5704 100644 --- a/src/runtime/slice.go +++ b/src/runtime/slice.go @@ -195,21 +195,17 @@ func growslice(et *_type, old slice, cap int) slice { var p unsafe.Pointer if et.kind&kindNoPointers != 0 { p = mallocgc(capmem, nil, false) - memmove(p, old.array, lenmem) // The append() that calls growslice is going to overwrite from old.len to cap (which will be the new length). // Only clear the part that will not be overwritten. memclrNoHeapPointers(add(p, newlenmem), capmem-newlenmem) } else { // Note: can't use rawmem (which avoids zeroing of memory), because then GC can scan uninitialized memory. p = mallocgc(capmem, et, true) - if !writeBarrier.enabled { - memmove(p, old.array, lenmem) - } else { - for i := uintptr(0); i < lenmem; i += et.size { - typedmemmove(et, add(p, i), add(old.array, i)) - } + if writeBarrier.enabled { + bulkBarrierPreWrite(uintptr(p), uintptr(old.array), lenmem) } } + memmove(p, old.array, lenmem) return slice{p, old.len, newcap} } -- 2.50.0