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[dev.ssa] cmd/compile: reuse sparse sets across compiler passes

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Cache sparse sets in the function so they can be reused by subsequent
compiler passes.

benchmark                        old ns/op     new ns/op     delta
BenchmarkDSEPass-8               206945        180022        -13.01%
BenchmarkDSEPassBlock-8          5286103       2614054       -50.55%
BenchmarkCSEPass-8               1790277       1790655       +0.02%
BenchmarkCSEPassBlock-8          18083588      18112771      +0.16%
BenchmarkDeadcodePass-8          59837         41375         -30.85%
BenchmarkDeadcodePassBlock-8     1651575       511169        -69.05%
BenchmarkMultiPass-8             531529        427506        -19.57%
BenchmarkMultiPassBlock-8        7033496       4487814       -36.19%

benchmark                        old allocs     new allocs     delta
BenchmarkDSEPass-8               11             4              -63.64%
BenchmarkDSEPassBlock-8          599            120            -79.97%
BenchmarkCSEPass-8               18             18             +0.00%
BenchmarkCSEPassBlock-8          2700           2700           +0.00%
BenchmarkDeadcodePass-8          4              3              -25.00%
BenchmarkDeadcodePassBlock-8     30             9              -70.00%
BenchmarkMultiPass-8             24             20             -16.67%
BenchmarkMultiPassBlock-8        1800           1000           -44.44%

benchmark                        old bytes     new bytes     delta
BenchmarkDSEPass-8               221367        142           -99.94%
BenchmarkDSEPassBlock-8          3695207       3846          -99.90%
BenchmarkCSEPass-8               303328        303328        +0.00%
BenchmarkCSEPassBlock-8          5006400       5006400       +0.00%
BenchmarkDeadcodePass-8          84232         10506         -87.53%
BenchmarkDeadcodePassBlock-8     1274940       163680        -87.16%
BenchmarkMultiPass-8             608674        313834        -48.44%
BenchmarkMultiPassBlock-8        9906001       5003450       -49.49%

Change-Id: Ib1fa58c7f494b374d1a4bb9cffbc2c48377b59d3
Reviewed-on: https://go-review.googlesource.com/19100
Reviewed-by: David Chase <drchase@google.com>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Todd Neal 2016-01-28 22:19:46 -06:00
parent 88b230eaa6
commit f962f33035
8 changed files with 150 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
src/cmd/compile/internal/ssa/deadcode.go
View File

@ -134,7 +134,8 @@ func deadcode(f *Func) {
live := liveValues(f, reachable)
// Remove dead & duplicate entries from namedValues map.
s := newSparseSet(f.NumValues())
s := f.newSparseSet(f.NumValues())
defer f.retSparseSet(s)
i := 0
for _, name := range f.Names {
j := 0

9
src/cmd/compile/internal/ssa/deadstore.go
View File

@ -10,9 +10,12 @@ package ssa
// This implementation only works within a basic block. TODO: use something more global.
func dse(f *Func) {
var stores []*Value
loadUse := newSparseSet(f.NumValues())
storeUse := newSparseSet(f.NumValues())
shadowed := newSparseSet(f.NumValues())
loadUse := f.newSparseSet(f.NumValues())
defer f.retSparseSet(loadUse)
storeUse := f.newSparseSet(f.NumValues())
defer f.retSparseSet(storeUse)
shadowed := f.newSparseSet(f.NumValues())
defer f.retSparseSet(shadowed)
for _, b := range f.Blocks {
// Find all the stores in this block. Categorize their uses:
// loadUse contains stores which are used by a subsequent load.

25
src/cmd/compile/internal/ssa/func.go
View File

@ -31,6 +31,8 @@ type Func struct {
freeValues *Value // free Values linked by argstorage[0]. All other fields except ID are 0/nil.
freeBlocks *Block // free Blocks linked by succstorage[0]. All other fields except ID are 0/nil.
scrSparse []*sparseSet // sparse sets to be re-used.
}
// NumBlocks returns an integer larger than the id of any Block in the Func.
@ -43,6 +45,29 @@ func (f *Func) NumValues() int {
return f.vid.num()
}
// newSparseSet returns a sparse set that can store at least up to n integers.
func (f *Func) newSparseSet(n int) *sparseSet {
for i, scr := range f.scrSparse {
if scr != nil && scr.cap() >= n {
f.scrSparse[i] = nil
scr.clear()
return scr
}
}
return newSparseSet(n)
}
// retSparseSet returns a sparse set to the function's cache to be reused by f.newSparseSet.
func (f *Func) retSparseSet(ss *sparseSet) {
for i, scr := range f.scrSparse {
if scr == nil {
f.scrSparse[i] = ss
return
}
}
f.scrSparse = append(f.scrSparse, ss)
}
// newValue allocates a new Value with the given fields and places it at the end of b.Values.
func (f *Func) newValue(op Op, t Type, b *Block, line int32) *Value {
var v *Value

6
src/cmd/compile/internal/ssa/layout.go
View File

@ -12,8 +12,10 @@ func layout(f *Func) {
scheduled := make([]bool, f.NumBlocks())
idToBlock := make([]*Block, f.NumBlocks())
indegree := make([]int, f.NumBlocks())
posdegree := newSparseSet(f.NumBlocks()) // blocks with positive remaining degree
zerodegree := newSparseSet(f.NumBlocks()) // blocks with zero remaining degree
posdegree := f.newSparseSet(f.NumBlocks()) // blocks with positive remaining degree
defer f.retSparseSet(posdegree)
zerodegree := f.newSparseSet(f.NumBlocks()) // blocks with zero remaining degree
defer f.retSparseSet(zerodegree)
// Initialize indegree of each block
for _, b := range f.Blocks {

101
src/cmd/compile/internal/ssa/passbm_test.go Normal file
View File

@ -0,0 +1,101 @@
// Copyright 2015 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
package ssa
import (
"fmt"
"testing"
)
const (
blockCount = 1000
passCount = 15000
)
type passFunc func(*Func)
func BenchmarkDSEPass(b *testing.B) { benchFnPass(b, dse, blockCount, genFunction) }
func BenchmarkDSEPassBlock(b *testing.B) { benchFnBlock(b, dse, genFunction) }
func BenchmarkCSEPass(b *testing.B) { benchFnPass(b, cse, blockCount, genFunction) }
func BenchmarkCSEPassBlock(b *testing.B) { benchFnBlock(b, cse, genFunction) }
func BenchmarkDeadcodePass(b *testing.B) { benchFnPass(b, deadcode, blockCount, genFunction) }
func BenchmarkDeadcodePassBlock(b *testing.B) { benchFnBlock(b, deadcode, genFunction) }
func multi(f *Func) {
cse(f)
dse(f)
deadcode(f)
}
func BenchmarkMultiPass(b *testing.B) { benchFnPass(b, multi, blockCount, genFunction) }
func BenchmarkMultiPassBlock(b *testing.B) { benchFnBlock(b, multi, genFunction) }
// benchFnPass runs passFunc b.N times across a single function.
func benchFnPass(b *testing.B, fn passFunc, size int, bg blockGen) {
b.ReportAllocs()
c := NewConfig("amd64", DummyFrontend{b}, nil, true)
fun := Fun(c, "entry", bg(size)...)
CheckFunc(fun.f)
b.ResetTimer()
for i := 0; i < b.N; i++ {
fn(fun.f)
b.StopTimer()
CheckFunc(fun.f)
b.StartTimer()
}
}
// benchFnPass runs passFunc across a function with b.N blocks.
func benchFnBlock(b *testing.B, fn passFunc, bg blockGen) {
b.ReportAllocs()
c := NewConfig("amd64", DummyFrontend{b}, nil, true)
fun := Fun(c, "entry", bg(b.N)...)
CheckFunc(fun.f)
b.ResetTimer()
for i := 0; i < passCount; i++ {
fn(fun.f)
}
b.StopTimer()
}
func genFunction(size int) []bloc {
var blocs []bloc
elemType := &TypeImpl{Size_: 8, Name: "testtype"}
ptrType := &TypeImpl{Size_: 8, Ptr: true, Name: "testptr", Elem_: elemType} // dummy for testing
valn := func(s string, m, n int) string { return fmt.Sprintf("%s%d-%d", s, m, n) }
blocs = append(blocs,
Bloc("entry",
Valu(valn("store", 0, 4), OpArg, TypeMem, 0, ".mem"),
Valu("sb", OpSB, TypeInvalid, 0, nil),
Goto(blockn(1)),
),
)
for i := 1; i < size+1; i++ {
blocs = append(blocs, Bloc(blockn(i),
Valu(valn("v", i, 0), OpConstBool, TypeBool, 1, nil),
Valu(valn("addr", i, 1), OpAddr, ptrType, 0, nil, "sb"),
Valu(valn("addr", i, 2), OpAddr, ptrType, 0, nil, "sb"),
Valu(valn("addr", i, 3), OpAddr, ptrType, 0, nil, "sb"),
Valu(valn("zero", i, 1), OpZero, TypeMem, 8, nil, valn("addr", i, 3),
valn("store", i-1, 4)),
Valu(valn("store", i, 1), OpStore, TypeMem, 0, nil, valn("addr", i, 1),
valn("v", i, 0), valn("zero", i, 1)),
Valu(valn("store", i, 2), OpStore, TypeMem, 0, nil, valn("addr", i, 2),
valn("v", i, 0), valn("store", i, 1)),
Valu(valn("store", i, 3), OpStore, TypeMem, 0, nil, valn("addr", i, 1),
valn("v", i, 0), valn("store", i, 2)),
Valu(valn("store", i, 4), OpStore, TypeMem, 0, nil, valn("addr", i, 3),
valn("v", i, 0), valn("store", i, 3)),
Goto(blockn(i+1))))
}
blocs = append(blocs,
Bloc(blockn(size+1), Goto("exit")),
Bloc("exit", Exit("store0-4")),
)
return blocs
}

3
src/cmd/compile/internal/ssa/regalloc.go
View File

@ -559,7 +559,8 @@ func (s *regAllocState) compatRegs(t Type) regMask {
}
func (s *regAllocState) regalloc(f *Func) {
liveSet := newSparseSet(f.NumValues())
liveSet := f.newSparseSet(f.NumValues())
defer f.retSparseSet(liveSet)
var oldSched []*Value
var phis []*Value
var phiRegs []register

4
src/cmd/compile/internal/ssa/sparseset.go
View File

@ -18,6 +18,10 @@ func newSparseSet(n int) *sparseSet {
return &sparseSet{nil, make([]int, n)}
}
func (s *sparseSet) cap() int {
return len(s.sparse)
}
func (s *sparseSet) size() int {
return len(s.dense)
}

9
src/cmd/compile/internal/ssa/stackalloc.go
View File

@ -182,8 +182,10 @@ func (s *stackAllocState) stackalloc() {
func (s *stackAllocState) computeLive(spillLive [][]ID) {
s.live = make([][]ID, s.f.NumBlocks())
var phis []*Value
live := newSparseSet(s.f.NumValues())
t := newSparseSet(s.f.NumValues())
live := s.f.newSparseSet(s.f.NumValues())
defer s.f.retSparseSet(live)
t := s.f.newSparseSet(s.f.NumValues())
defer s.f.retSparseSet(t)
// Instead of iterating over f.Blocks, iterate over their postordering.
// Liveness information flows backward, so starting at the end
@ -271,7 +273,8 @@ func (f *Func) setHome(v *Value, loc Location) {
func (s *stackAllocState) buildInterferenceGraph() {
f := s.f
s.interfere = make([][]ID, f.NumValues())
live := newSparseSet(f.NumValues())
live := f.newSparseSet(f.NumValues())
defer f.retSparseSet(live)
for _, b := range f.Blocks {
// Propagate liveness backwards to the start of the block.
// Two values interfere if one is defined while the other is live.