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fmt: benchmark floating point.

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mallocs per Sprintf("%x"): 1
mallocs per Sprintf("%g"): 4

R=golang-dev, gri
CC=golang-dev
https://golang.org/cl/5449106
This commit is contained in:
Rob Pike 2011-12-06 08:40:16 -08:00
parent 972b98c135
commit 66410bac3d
1 changed files with 29 additions and 14 deletions
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43
src/pkg/fmt/fmt_test.go
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@ -500,69 +500,84 @@ func BenchmarkSprintfPrefixedInt(b *testing.B) {
} }
} }
func BenchmarkSprintfFloat(b *testing.B) {
for i := 0; i < b.N; i++ {
Sprintf("%g", 5.23184)
}
}
func TestCountMallocs(t *testing.T) { func TestCountMallocs(t *testing.T) {
if testing.Short() { if testing.Short() {
return return
} }
const N = 100
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs := 0 - runtime.MemStats.Mallocs mallocs := 0 - runtime.MemStats.Mallocs
for i := 0; i < 100; i++ { for i := 0; i < N; i++ {
Sprintf("") Sprintf("")
} }
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"\"): %d\n", mallocs/100) Printf("mallocs per Sprintf(\"\"): %d\n", mallocs/N)
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < 100; i++ { for i := 0; i < N; i++ {
Sprintf("xxx") Sprintf("xxx")
} }
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"xxx\"): %d\n", mallocs/100) Printf("mallocs per Sprintf(\"xxx\"): %d\n", mallocs/N)
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < 100; i++ { for i := 0; i < N; i++ {
Sprintf("%x", i) Sprintf("%x", i)
} }
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"%%x\"): %d\n", mallocs/100) Printf("mallocs per Sprintf(\"%%x\"): %d\n", mallocs/N)
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < 100; i++ { for i := 0; i < N; i++ {
Sprintf("%s", "hello") Sprintf("%s", "hello")
} }
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"%%s\"): %d\n", mallocs/100) Printf("mallocs per Sprintf(\"%%s\"): %d\n", mallocs/N)
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < 100; i++ { for i := 0; i < N; i++ {
Sprintf("%x %x", i, i) Sprintf("%x %x", i, i)
} }
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"%%x %%x\"): %d\n", mallocs/100) Printf("mallocs per Sprintf(\"%%x %%x\"): %d\n", mallocs/N)
runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
Sprintf("%g", 3.14159)
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"%%g\"): %d\n", mallocs/N)
buf := new(bytes.Buffer) buf := new(bytes.Buffer)
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < 100; i++ { for i := 0; i < N; i++ {
buf.Reset() buf.Reset()
Fprintf(buf, "%x %x %x", i, i, i) Fprintf(buf, "%x %x %x", i, i, i)
} }
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Fprintf(buf, \"%%x %%x %%x\"): %d\n", mallocs/100) Printf("mallocs per Fprintf(buf, \"%%x %%x %%x\"): %d\n", mallocs/N)
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < 100; i++ { for i := 0; i < N; i++ {
buf.Reset() buf.Reset()
Fprintf(buf, "%s", "hello") Fprintf(buf, "%s", "hello")
} }
runtime.UpdateMemStats() runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Fprintf(buf, \"%%s\"): %d\n", mallocs/100) Printf("mallocs per Fprintf(buf, \"%%s\"): %d\n", mallocs/N)
} }
type flagPrinter struct{} type flagPrinter struct{}