code review 5987045: runtime: make GC stats per-M

runtime: make GC stats per-M
This is factored out part of:
http://codereview.appspot.com/5279048/
(Parallel GC)

benchmark                             old ns/op    new ns/op    delta
garbage.BenchmarkParser              3999106750   3975026500   -0.60%
garbage.BenchmarkParser-2            3720553750   3719196500   -0.04%
garbage.BenchmarkParser-4            3502857000   3474980500   -0.80%
garbage.BenchmarkParser-8            3375448000   3341310500   -1.01%
garbage.BenchmarkParserLastPause      329401000    324097000   -1.61%
garbage.BenchmarkParserLastPause-2    208953000    214222000   +2.52%
garbage.BenchmarkParserLastPause-4    110933000    111656000   +0.65%
garbage.BenchmarkParserLastPause-8     71969000     78230000   +8.70%
garbage.BenchmarkParserPause          230808842    197237400  -14.55%
garbage.BenchmarkParserPause-2        123674365    125197595   +1.23%
garbage.BenchmarkParserPause-4         80518525     85710333   +6.45%
garbage.BenchmarkParserPause-8         58310243     56940512   -2.35%
garbage.BenchmarkTree2                 31471700     31289400   -0.58%
garbage.BenchmarkTree2-2               21536800     21086300   -2.09%
garbage.BenchmarkTree2-4               11074700     10880000   -1.76%
garbage.BenchmarkTree2-8                7568600      7351400   -2.87%
garbage.BenchmarkTree2LastPause       314664000    312840000   -0.58%
garbage.BenchmarkTree2LastPause-2     215319000    210815000   -2.09%
garbage.BenchmarkTree2LastPause-4     110698000    108751000   -1.76%
garbage.BenchmarkTree2LastPause-8      75635000     73463000   -2.87%
garbage.BenchmarkTree2Pause           174280857    173147571   -0.65%
garbage.BenchmarkTree2Pause-2         131332714    129665761   -1.27%
garbage.BenchmarkTree2Pause-4          93803095     93422904   -0.41%
garbage.BenchmarkTree2Pause-8          86242333     85146761   -1.27%

[dvyukov, 2012-04-05 14:20:50]

Hello golang-dev@googlegroups.com,

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

[rsc, 2012-04-05 14:30:07]

The code looks fine but this is the first CL making
changes to the garbage collector itself.  I'd like to set
a convention that when we make changes like these
we include benchmarks measuring the effect in the 
CL description.  

Please run make bench in go/test/bench/garbage
with varying numbers of procs before and after this
change and add a summary (like what benchcmp prints,
maybe) to the CL description.

go/test/bench/garbage may not be a good set of tests.
If you have any other tests that should be there, let's
add them (in a separate CL).

Thanks.
Russ

http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c
File src/pkg/runtime/mgc0.c (right):

http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c#newcod...
src/pkg/runtime/mgc0.c:554: m->gcstats.nhandoff += 1;
++

http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c#newcod...
src/pkg/runtime/mgc0.c:940: cachestats(0);
Please use nil instead of 0 when you need a pointer.

http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c#newcod...
src/pkg/runtime/mgc0.c:1038: cachestats(0);
Same.

[dvyukov, 2012-04-05 16:09:00]

On 2012/04/05 14:30:07, rsc wrote:
> The code looks fine but this is the first CL making
> changes to the garbage collector itself.  I'd like to set
> a convention that when we make changes like these
> we include benchmarks measuring the effect in the 
> CL description.  
> 
> Please run make bench in go/test/bench/garbage
> with varying numbers of procs before and after this
> change and add a summary (like what benchcmp prints,
> maybe) to the CL description.
> 
> go/test/bench/garbage may not be a good set of tests.
> If you have any other tests that should be there, let's
> add them (in a separate CL).

I've added results of test/bench/garbage benchmarks (parser and tree2).
I think that big differences on parser are caused by the fact that different
number of garbage collections was executed during the runs.


> http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c
> File src/pkg/runtime/mgc0.c (right):
> 
>
http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c#newcod...
> src/pkg/runtime/mgc0.c:554: m->gcstats.nhandoff += 1;
> ++
> 
>
http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c#newcod...
> src/pkg/runtime/mgc0.c:940: cachestats(0);
> Please use nil instead of 0 when you need a pointer.
> 
>
http://codereview.appspot.com/5987045/diff/1002/src/pkg/runtime/mgc0.c#newcod...
> src/pkg/runtime/mgc0.c:1038: cachestats(0);
> Same.

Done. PTAL.

[rsc, 2012-04-05 16:35:01]

LGTM

Can you please sort the lines in the CL description?

garbage.BenchmarkParser              3999106750   3975026500   -0.60%
garbage.BenchmarkParser-2            3720553750   3719196500   -0.04%
garbage.BenchmarkParser-4            3502857000   3474980500   -0.80%
garbage.BenchmarkParser-8            3375448000   3341310500   -1.01%
garbage.BenchmarkParserLastPause      329401000    324097000   -1.61%
garbage.BenchmarkParserLastPause-2    208953000    214222000   +2.52%
garbage.BenchmarkParserLastPause-4    110933000    111656000   +0.65%
garbage.BenchmarkParserLastPause-8     71969000     78230000   +8.70%
garbage.BenchmarkParserPause          230808842    197237400  -14.55%
garbage.BenchmarkParserPause-2        123674365    125197595   +1.23%
garbage.BenchmarkParserPause-4         80518525     85710333   +6.45%
garbage.BenchmarkParserPause-8         58310243     56940512   -2.35%
garbage.BenchmarkTree2                 31471700     31289400   -0.58%
garbage.BenchmarkTree2-2               21536800     21086300   -2.09%
garbage.BenchmarkTree2-4               11074700     10880000   -1.76%
garbage.BenchmarkTree2-8                7568600      7351400   -2.87%
garbage.BenchmarkTree2LastPause       314664000    312840000   -0.58%
garbage.BenchmarkTree2LastPause-2     215319000    210815000   -2.09%
garbage.BenchmarkTree2LastPause-4     110698000    108751000   -1.76%
garbage.BenchmarkTree2LastPause-8      75635000     73463000   -2.87%
garbage.BenchmarkTree2Pause           174280857    173147571   -0.65%
garbage.BenchmarkTree2Pause-2         131332714    129665761   -1.27%
garbage.BenchmarkTree2Pause-4          93803095     93422904   -0.41%
garbage.BenchmarkTree2Pause-8          86242333     85146761   -1.27%

[dvyukov, 2012-04-05 16:48:41]

*** Submitted as http://code.google.com/p/go/source/detail?r=dd0b27040a5a ***

runtime: make GC stats per-M
This is factored out part of:
http://codereview.appspot.com/5279048/
(Parallel GC)

benchmark                             old ns/op    new ns/op    delta
garbage.BenchmarkParser              3999106750   3975026500   -0.60%
garbage.BenchmarkParser-2            3720553750   3719196500   -0.04%
garbage.BenchmarkParser-4            3502857000   3474980500   -0.80%
garbage.BenchmarkParser-8            3375448000   3341310500   -1.01%
garbage.BenchmarkParserLastPause      329401000    324097000   -1.61%
garbage.BenchmarkParserLastPause-2    208953000    214222000   +2.52%
garbage.BenchmarkParserLastPause-4    110933000    111656000   +0.65%
garbage.BenchmarkParserLastPause-8     71969000     78230000   +8.70%
garbage.BenchmarkParserPause          230808842    197237400  -14.55%
garbage.BenchmarkParserPause-2        123674365    125197595   +1.23%
garbage.BenchmarkParserPause-4         80518525     85710333   +6.45%
garbage.BenchmarkParserPause-8         58310243     56940512   -2.35%
garbage.BenchmarkTree2                 31471700     31289400   -0.58%
garbage.BenchmarkTree2-2               21536800     21086300   -2.09%
garbage.BenchmarkTree2-4               11074700     10880000   -1.76%
garbage.BenchmarkTree2-8                7568600      7351400   -2.87%
garbage.BenchmarkTree2LastPause       314664000    312840000   -0.58%
garbage.BenchmarkTree2LastPause-2     215319000    210815000   -2.09%
garbage.BenchmarkTree2LastPause-4     110698000    108751000   -1.76%
garbage.BenchmarkTree2LastPause-8      75635000     73463000   -2.87%
garbage.BenchmarkTree2Pause           174280857    173147571   -0.65%
garbage.BenchmarkTree2Pause-2         131332714    129665761   -1.27%
garbage.BenchmarkTree2Pause-4          93803095     93422904   -0.41%
garbage.BenchmarkTree2Pause-8          86242333     85146761   -1.27%

R=rsc
CC=golang-dev
http://codereview.appspot.com/5987045