From: aimuz Date: Sun, 28 Apr 2024 01:52:06 +0000 (+0000) Subject: encoding/json: optimize field sorting with slices and cmp X-Git-Tag: go1.23rc1~501 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=9e0685f9c24ff80a7e710e764c1090c680a5095c;p=gostls13.git encoding/json: optimize field sorting with slices and cmp Refactor field sorting in typeFields to use slices.SortFunc and cmp.Compare, resulting in performance improvements in cache misses and slight increases in hit latency. Memory allocation and operation counts also reduced significantly for cache misses. goos: darwin goarch: arm64 pkg: encoding/json cpu: Apple M2 Max │ old.txt │ new.txt │ │ sec/op │ sec/op vs base │ TypeFieldsCache/MissTypes1-12 5.068µ ± 2% 5.032µ ± 1% ~ (p=0.055 n=10) TypeFieldsCache/MissTypes10-12 15.22µ ± 2% 14.79µ ± 2% -2.84% (p=0.000 n=10) TypeFieldsCache/MissTypes100-12 98.40µ ± 3% 94.72µ ± 1% -3.73% (p=0.002 n=10) TypeFieldsCache/MissTypes1000-12 860.3µ ± 3% 840.7µ ± 1% ~ (p=0.105 n=10) TypeFieldsCache/MissTypes10000-12 8.092m ± 3% 7.987m ± 4% ~ (p=0.280 n=10) TypeFieldsCache/MissTypes100000-12 80.90m ± 9% 80.62m ± 2% ~ (p=0.631 n=10) TypeFieldsCache/MissTypes1000000-12 1009.5m ± 7% 933.8m ± 7% -7.50% (p=0.011 n=10) TypeFieldsCache/HitTypes1-12 1.554n ± 3% 1.617n ± 3% +4.05% (p=0.004 n=10) TypeFieldsCache/HitTypes10-12 1.575n ± 1% 1.624n ± 6% +3.14% (p=0.000 n=10) TypeFieldsCache/HitTypes100-12 1.566n ± 1% 1.627n ± 5% +3.86% (p=0.000 n=10) TypeFieldsCache/HitTypes1000-12 1.526n ± 4% 1.596n ± 3% +4.55% (p=0.001 n=10) TypeFieldsCache/HitTypes10000-12 1.506n ± 0% 1.573n ± 3% +4.41% (p=0.000 n=10) TypeFieldsCache/HitTypes100000-12 1.480n ± 1% 1.529n ± 7% +3.35% (p=0.001 n=10) TypeFieldsCache/HitTypes1000000-12 1.473n ± 2% 1.468n ± 2% ~ (p=0.739 n=10) geomean 1.371µ 1.374µ +0.25% │ old.txt │ new.txt │ │ B/op │ B/op vs base │ TypeFieldsCache/MissTypes1-12 2.023Ki ± 0% 2.000Ki ± 0% -1.16% (p=0.000 n=10) TypeFieldsCache/MissTypes10-12 10.95Ki ± 0% 10.71Ki ± 0% -2.17% (p=0.000 n=10) TypeFieldsCache/MissTypes100-12 101.91Ki ± 0% 99.53Ki ± 0% -2.34% (p=0.000 n=10) TypeFieldsCache/MissTypes1000-12 1044.3Ki ± 0% 1020.8Ki ± 0% -2.25% (p=0.000 n=10) TypeFieldsCache/MissTypes10000-12 9.957Mi ± 0% 9.730Mi ± 0% -2.29% (p=0.000 n=10) TypeFieldsCache/MissTypes100000-12 97.79Mi ± 0% 95.50Mi ± 0% -2.34% (p=0.000 n=10) TypeFieldsCache/MissTypes1000000-12 1018.4Mi ± 0% 995.5Mi ± 0% -2.25% (p=0.000 n=10) TypeFieldsCache/HitTypes1-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes10-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes100-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes1000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes10000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes100000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes1000000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ geomean ² -1.06% ² ¹ all samples are equal ² summaries must be >0 to compute geomean │ old.txt │ new.txt │ │ allocs/op │ allocs/op vs base │ TypeFieldsCache/MissTypes1-12 46.00 ± 0% 45.00 ± 0% -2.17% (p=0.000 n=10) TypeFieldsCache/MissTypes10-12 215.0 ± 0% 205.0 ± 0% -4.65% (p=0.000 n=10) TypeFieldsCache/MissTypes100-12 1.845k ± 0% 1.745k ± 0% -5.42% (p=0.000 n=10) TypeFieldsCache/MissTypes1000-12 18.08k ± 0% 17.08k ± 0% -5.53% (p=0.000 n=10) TypeFieldsCache/MissTypes10000-12 180.3k ± 0% 170.3k ± 0% -5.55% (p=0.000 n=10) TypeFieldsCache/MissTypes100000-12 1.804M ± 0% 1.704M ± 0% -5.54% (p=0.000 n=10) TypeFieldsCache/MissTypes1000000-12 18.04M ± 0% 17.04M ± 0% -5.54% (p=0.000 n=10) TypeFieldsCache/HitTypes1-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes10-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes100-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes1000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes10000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes100000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ TypeFieldsCache/HitTypes1000000-12 0.000 ± 0% 0.000 ± 0% ~ (p=1.000 n=10) ¹ geomean ² -2.49% ² ¹ all samples are equal ² summaries must be >0 to compute geomean Change-Id: I62b8f524f5747f4f1b9241a1d849efeef1851049 GitHub-Last-Rev: d16772d4fb44f76e2688e15f1bdfc7db14bb55c6 GitHub-Pull-Request: golang/go#67046 Reviewed-on: https://go-review.googlesource.com/c/go/+/581895 LUCI-TryBot-Result: Go LUCI Auto-Submit: Ian Lance Taylor Reviewed-by: Ian Lance Taylor Reviewed-by: Joedian Reid --- diff --git a/src/encoding/json/encode.go b/src/encoding/json/encode.go index 0035a65cfc..bd55c7caf0 100644 --- a/src/encoding/json/encode.go +++ b/src/encoding/json/encode.go @@ -12,13 +12,13 @@ package json import ( "bytes" + "cmp" "encoding" "encoding/base64" "fmt" "math" "reflect" "slices" - "sort" "strconv" "strings" "sync" @@ -1162,21 +1162,23 @@ func typeFields(t reflect.Type) structFields { } } - sort.Slice(fields, func(i, j int) bool { - x := fields + slices.SortFunc(fields, func(a, b field) int { // sort field by name, breaking ties with depth, then // breaking ties with "name came from json tag", then // breaking ties with index sequence. - if x[i].name != x[j].name { - return x[i].name < x[j].name + if c := strings.Compare(a.name, b.name); c != 0 { + return c } - if len(x[i].index) != len(x[j].index) { - return len(x[i].index) < len(x[j].index) + if c := cmp.Compare(len(a.index), len(b.index)); c != 0 { + return c } - if x[i].tag != x[j].tag { - return x[i].tag + if a.tag != b.tag { + if a.tag { + return -1 + } + return +1 } - return slices.Compare(x[i].index, x[j].index) == -1 + return slices.Compare(a.index, b.index) }) // Delete all fields that are hidden by the Go rules for embedded fields,