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fmt: make the malloc test check its counts

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Discover than %g is now down to 1 malloc from 2 from 4.
Have fun with funcs.

R=golang-dev, rsc
CC=golang-dev
https://golang.org/cl/5504077
This commit is contained in:
Rob Pike 2011-12-22 15:16:06 -08:00
parent 102c1a7c96
commit 07db252222
1 changed files with 31 additions and 67 deletions
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98
src/pkg/fmt/fmt_test.go
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@ -506,78 +506,42 @@ func BenchmarkSprintfFloat(b *testing.B) {
}
}
var mallocBuf bytes.Buffer
var mallocTest = []struct {
count int
desc string
fn func()
}{
{0, `Sprintf("")`, func() { Sprintf("") }},
{1, `Sprintf("xxx")`, func() { Sprintf("xxx") }},
{1, `Sprintf("%x")`, func() { Sprintf("%x", 7) }},
{2, `Sprintf("%s")`, func() { Sprintf("%s", "hello") }},
{1, `Sprintf("%x %x")`, func() { Sprintf("%x", 7, 112) }},
{1, `Sprintf("%g")`, func() { Sprintf("%g", 3.14159) }},
{0, `Fprintf(buf, "%x %x %x")`, func() { mallocBuf.Reset(); Fprintf(&mallocBuf, "%x %x %x", 7, 8, 9) }},
{1, `Fprintf(buf, "%s")`, func() { mallocBuf.Reset(); Fprintf(&mallocBuf, "%s", "hello") }},
}
var _ bytes.Buffer
func TestCountMallocs(t *testing.T) {
if testing.Short() {
return
}
const N = 100
runtime.UpdateMemStats()
mallocs := 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
Sprintf("")
for _, mt := range mallocTest {
const N = 100
runtime.UpdateMemStats()
mallocs := 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
mt.fn()
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
if mallocs/N != uint64(mt.count) {
t.Errorf("%s: expected %d mallocs, got %d", mt.desc, mt.count, mallocs/N)
}
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"\"): %d\n", mallocs/N)
runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
Sprintf("xxx")
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"xxx\"): %d\n", mallocs/N)
runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
Sprintf("%x", i)
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"%%x\"): %d\n", mallocs/N)
runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
Sprintf("%s", "hello")
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Sprintf(\"%%s\"): %d\n", mallocs/N)
runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
Sprintf("%x %x", i, i)
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
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)
runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
buf.Reset()
Fprintf(buf, "%x %x %x", i, i, i)
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Fprintf(buf, \"%%x %%x %%x\"): %d\n", mallocs/N)
runtime.UpdateMemStats()
mallocs = 0 - runtime.MemStats.Mallocs
for i := 0; i < N; i++ {
buf.Reset()
Fprintf(buf, "%s", "hello")
}
runtime.UpdateMemStats()
mallocs += runtime.MemStats.Mallocs
Printf("mallocs per Fprintf(buf, \"%%s\"): %d\n", mallocs/N)
}
type flagPrinter struct{}