diff options
author | Rob Pike <r@golang.org> | 2014-09-09 11:45:46 -0700 |
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committer | Rob Pike <r@golang.org> | 2014-09-09 11:45:46 -0700 |
commit | f447de583f8a101c406a2ed2e54300bdabb90034 (patch) | |
tree | 8f6386d0ecf499003b5d590a0e3c30c32c15c6d3 | |
parent | 49384de5d72f451ca24e4d30847e1e02f7af6068 (diff) | |
download | go-f447de583f8a101c406a2ed2e54300bdabb90034.tar.gz |
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://codereview.appspot.com/142760044
-rw-r--r-- | src/fmt/fmt_test.go | 11 |
1 files changed, 7 insertions, 4 deletions
diff --git a/src/fmt/fmt_test.go b/src/fmt/fmt_test.go index 8c577949a..89dde2b64 100644 --- a/src/fmt/fmt_test.go +++ b/src/fmt/fmt_test.go @@ -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 |