Commit eafa4fff authored by Rob Pike's avatar Rob Pike

fmt: fix allocation test

With new interface allocation rules, the old counts were wrong and
so was the commentary.

LGTM=rsc
R=rsc
CC=golang-codereviews
https://golang.org/cl/142760044
parent b6571a07
......@@ -855,6 +855,7 @@ func BenchmarkManyArgs(b *testing.B) {
}
var mallocBuf bytes.Buffer
var mallocPointer *int // A pointer so we know the interface value won't allocate.
var mallocTest = []struct {
count int
......@@ -866,11 +867,13 @@ var mallocTest = []struct {
{1, `Sprintf("%x")`, func() { Sprintf("%x", 7) }},
{2, `Sprintf("%s")`, func() { Sprintf("%s", "hello") }},
{1, `Sprintf("%x %x")`, func() { Sprintf("%x %x", 7, 112) }},
// For %g we use a float32, not float64, to guarantee passing the argument
// does not need to allocate memory to store the result in a pointer-sized word.
{2, `Sprintf("%g")`, func() { Sprintf("%g", float32(3.14159)) }},
{0, `Fprintf(buf, "%x %x %x")`, func() { mallocBuf.Reset(); Fprintf(&mallocBuf, "%x %x %x", 7, 8, 9) }},
{2, `Sprintf("%g")`, func() { Sprintf("%g", float32(3.14159)) }}, // TODO: Can this be 1?
{1, `Fprintf(buf, "%s")`, func() { mallocBuf.Reset(); Fprintf(&mallocBuf, "%s", "hello") }},
// If the interface value doesn't need to allocate, amortized allocation overhead should be zero.
{0, `Fprintf(buf, "%x %x %x")`, func() {
mallocBuf.Reset()
Fprintf(&mallocBuf, "%x %x %x", mallocPointer, mallocPointer, mallocPointer)
}},
}
var _ bytes.Buffer
......
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