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regexp/syntax: don't do both linear and binary sesarch in MatchRunePos
MatchRunePos is a significant element of regexp performance, so some attention to optimization is appropriate. Before this CL, a non-matching rune would do both a linear search in the first four entries, and a binary search over all the entries. Change the code to optimize for the common case of two runes, to only do a linear search when there are up to four entries, and to only do a binary search when there are more than four entries. Updates #26623 name old time/op new time/op delta Find-12 260ns ± 1% 275ns ± 7% +5.84% (p=0.000 n=8+10) FindAllNoMatches-12 144ns ± 9% 143ns ±12% ~ (p=0.187 n=10+10) FindString-12 256ns ± 4% 254ns ± 1% ~ (p=0.357 n=9+8) FindSubmatch-12 587ns ±12% 593ns ±11% ~ (p=0.516 n=10+10) FindStringSubmatch-12 534ns ±12% 525ns ±14% ~ (p=0.565 n=10+10) Literal-12 104ns ±14% 106ns ±11% ~ (p=0.145 n=10+10) NotLiteral-12 1.51µs ± 8% 1.47µs ± 2% ~ (p=0.508 n=10+9) MatchClass-12 2.47µs ± 1% 2.26µs ± 6% -8.55% (p=0.000 n=8+10) MatchClass_InRange-12 2.18µs ± 5% 2.25µs ±11% +2.85% (p=0.009 n=9+10) ReplaceAll-12 2.35µs ± 6% 2.08µs ±23% -11.59% (p=0.010 n=9+10) AnchoredLiteralShortNonMatch-12 93.2ns ± 9% 93.2ns ±11% ~ (p=0.716 n=10+10) AnchoredLiteralLongNonMatch-12 118ns ±10% 117ns ± 9% ~ (p=0.802 n=10+10) AnchoredShortMatch-12 142ns ± 1% 141ns ± 1% -0.53% (p=0.007 n=8+8) AnchoredLongMatch-12 303ns ± 9% 304ns ± 6% ~ (p=0.724 n=10+10) OnePassShortA-12 620ns ± 1% 618ns ± 9% ~ (p=0.162 n=8+10) NotOnePassShortA-12 599ns ± 8% 568ns ± 1% -5.21% (p=0.000 n=10+8) OnePassShortB-12 525ns ± 7% 489ns ± 1% -6.93% (p=0.000 n=10+8) NotOnePassShortB-12 449ns ± 9% 431ns ±11% -4.05% (p=0.033 n=10+10) OnePassLongPrefix-12 119ns ± 6% 114ns ± 0% -3.88% (p=0.006 n=10+9) OnePassLongNotPrefix-12 420ns ± 9% 410ns ± 7% ~ (p=0.645 n=10+9) MatchParallelShared-12 376ns ± 0% 375ns ± 0% -0.45% (p=0.003 n=8+10) MatchParallelCopied-12 39.4ns ± 1% 39.1ns ± 0% -0.55% (p=0.004 n=10+9) QuoteMetaAll-12 139ns ± 7% 142ns ± 7% ~ (p=0.445 n=10+10) QuoteMetaNone-12 56.7ns ± 0% 61.3ns ± 7% +8.03% (p=0.001 n=8+10) Match/Easy0/32-12 83.4ns ± 7% 83.1ns ± 8% ~ (p=0.541 n=10+10) Match/Easy0/1K-12 417ns ± 8% 394ns ± 6% ~ (p=0.059 n=10+9) Match/Easy0/32K-12 7.05µs ± 8% 7.30µs ± 9% ~ (p=0.190 n=10+10) Match/Easy0/1M-12 291µs ±17% 284µs ±10% ~ (p=0.481 n=10+10) Match/Easy0/32M-12 9.89ms ± 4% 10.27ms ± 8% ~ (p=0.315 n=10+10) Match/Easy0i/32-12 1.13µs ± 1% 1.14µs ± 1% +1.51% (p=0.000 n=8+8) Match/Easy0i/1K-12 35.7µs ±11% 36.8µs ±10% ~ (p=0.143 n=10+10) Match/Easy0i/32K-12 1.70ms ± 7% 1.72ms ± 7% ~ (p=0.776 n=9+6) name old alloc/op new alloc/op delta Find-12 0.00B 0.00B ~ (all equal) FindAllNoMatches-12 0.00B 0.00B ~ (all equal) FindString-12 0.00B 0.00B ~ (all equal) FindSubmatch-12 48.0B ± 0% 48.0B ± 0% ~ (all equal) FindStringSubmatch-12 32.0B ± 0% 32.0B ± 0% ~ (all equal) name old allocs/op new allocs/op delta Find-12 0.00 0.00 ~ (all equal) FindAllNoMatches-12 0.00 0.00 ~ (all equal) FindString-12 0.00 0.00 ~ (all equal) FindSubmatch-12 1.00 ± 0% 1.00 ± 0% ~ (all equal) FindStringSubmatch-12 1.00 ± 0% 1.00 ± 0% ~ (all equal) name old speed new speed delta QuoteMetaAll-12 101MB/s ± 8% 99MB/s ± 7% ~ (p=0.529 n=10+10) QuoteMetaNone-12 458MB/s ± 0% 425MB/s ± 8% -7.22% (p=0.003 n=8+10) Match/Easy0/32-12 385MB/s ± 7% 386MB/s ± 7% ~ (p=0.579 n=10+10) Match/Easy0/1K-12 2.46GB/s ± 8% 2.60GB/s ± 6% ~ (p=0.065 n=10+9) Match/Easy0/32K-12 4.66GB/s ± 7% 4.50GB/s ±10% ~ (p=0.190 n=10+10) Match/Easy0/1M-12 3.63GB/s ±15% 3.70GB/s ± 9% ~ (p=0.481 n=10+10) Match/Easy0/32M-12 3.40GB/s ± 4% 3.28GB/s ± 8% ~ (p=0.315 n=10+10) Match/Easy0i/32-12 28.4MB/s ± 1% 28.0MB/s ± 1% -1.50% (p=0.000 n=8+8) Match/Easy0i/1K-12 28.8MB/s ±10% 27.9MB/s ±11% ~ (p=0.143 n=10+10) Match/Easy0i/32K-12 19.0MB/s ±14% 19.1MB/s ± 8% ~ (p=1.000 n=10+6) Change-Id: I238a451b36ad84b0f5534ff0af5c077a0d52d73a Reviewed-on: https://go-review.googlesource.com/130417 Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Ian Lance Taylor
parent
a21ae28f39
commit
3396034155
@ -201,8 +201,12 @@ func (i *Inst) MatchRune(r rune) bool {
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func (i *Inst) MatchRunePos(r rune) int {
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rune := i.Rune
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// Special case: single-rune slice is from literal string, not char class.
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if len(rune) == 1 {
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switch len(rune) {
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case 0:
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return noMatch
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case 1:
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// Special case: single-rune slice is from literal string, not char class.
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r0 := rune[0]
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if r == r0 {
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return 0
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@ -215,17 +219,25 @@ func (i *Inst) MatchRunePos(r rune) int {
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}
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}
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return noMatch
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}
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// Peek at the first few pairs.
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// Should handle ASCII well.
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for j := 0; j < len(rune) && j <= 8; j += 2 {
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if r < rune[j] {
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return noMatch
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case 2:
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if r >= rune[0] && r <= rune[1] {
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return 0
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}
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if r <= rune[j+1] {
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return j / 2
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return noMatch
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case 4, 6, 8:
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// Linear search for a few pairs.
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// Should handle ASCII well.
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for j := 0; j < len(rune); j += 2 {
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if r < rune[j] {
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return noMatch
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}
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if r <= rune[j+1] {
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return j / 2
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}
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}
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return noMatch
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}
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// Otherwise binary search.
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