code review 5371100: misc/benchcmp: benchmark comparison script

misc/benchcmp: benchmark comparison script

I've been using this since April and posted it on the
mailing list, but it seems worth having in the repository.
Not sure about the location.

[rsc, 2011-11-15 17:00:00]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[r, 2011-11-15 17:16:15]

LGTM

http://codereview.appspot.com/5371100/diff/3002/misc/benchcmp
File misc/benchcmp (right):

http://codereview.appspot.com/5371100/diff/3002/misc/benchcmp#newcode11
misc/benchcmp:11: echo '	gotest -bench . 2>&1 | tee old.txt' >&2
i think the tee here is confusing
why not just

gotest -bench . 2>&1

(also i'm disappointed but not surprised the 2>&1 is necessary)

http://codereview.appspot.com/5371100/diff/3002/misc/benchcmp#newcode20
misc/benchcmp:20: $1 ~ /Benchmark/ && $4 == "ns/op" {
/^Benchmark.*ns\/op/
is all you need.

http://codereview.appspot.com/5371100/diff/3002/misc/benchcmp#newcode39
misc/benchcmp:39: printf("no repeated benchmarks\n")
print "benchmp: no repeated benchmarks" > "/dev/stderr"

[rsc, 2011-11-15 17:18:01]

On Tue, Nov 15, 2011 at 12:16,  <r@golang.org> wrote:
> (also i'm disappointed but not surprised the 2>&1 is necessary)

i think we should make gotest print everything to stdout.
right now it prints nothing to stdout.
if you agree i will send a CL.

[r2, 2011-11-15 17:20:39]

On Nov 15, 2011, at 9:18 AM, Russ Cox wrote:

> On Tue, Nov 15, 2011 at 12:16,  <r@golang.org> wrote:
>> (also i'm disappointed but not surprised the 2>&1 is necessary)
> 
> i think we should make gotest print everything to stdout.
> right now it prints nothing to stdout.
> if you agree i will send a CL.

agreed

some scripts will be broken but i agree anyway

[rsc, 2011-11-15 17:44:01]

Now I have
	echo 'usage: benchcmp old.txt new.txt' >&2
	echo >&2
	echo 'Each input file should be gotest -bench output.' >&2
	echo 'Benchcmp compares the first and last result for each benchmark.' >&2
	exit 2

I kept the $4 == "ns/op" check, because it sanity checks
that the code agrees about what field is where.

[r, 2011-11-15 17:48:21]

LGTM

[rsc, 2011-11-15 17:49:27]

*** Submitted as http://code.google.com/p/go/source/detail?r=7a92d4f96c44 ***

misc/benchcmp: benchmark comparison script

I've been using this since April and posted it on the
mailing list, but it seems worth having in the repository.
Not sure about the location.

R=golang-dev, r, r
CC=golang-dev
http://codereview.appspot.com/5371100