code review 145790043: runtime: change minimum stack size to 2K.

runtime: change minimum stack size to 2K.

It will be 8K on windows because it needs 4K for the OS.
Similarly, plan9 will be 4K.

On linux/amd64, reduces size of 100,000 goroutines
from ~819MB to ~245MB.

Update issue 7514

[khr, 2014-09-16 21:42:06]

Hello golang-codereviews@googlegroups.com,

I'd like you to review this change to
https://khr%40golang.org@code.google.com/p/go/

[dvyukov, 2014-09-16 22:28:40]

https://codereview.appspot.com/145790043/diff/60001/src/runtime/proc.c
File src/runtime/proc.c (right):

https://codereview.appspot.com/145790043/diff/60001/src/runtime/proc.c#newcod...
src/runtime/proc.c:2203: if(siz >= StackMin - 4*sizeof(uintreg) - sizeof(void*))
please comment what is "4*sizeof(uintreg) - sizeof(void*)"

[khr1, 2014-09-17 00:09:49]

PTAL

On Tue, Sep 16, 2014 at 3:28 PM, <dvyukov@google.com> wrote:

>
> https://codereview.appspot.com/145790043/diff/60001/src/runtime/proc.c
> File src/runtime/proc.c (right):
>
> https://codereview.appspot.com/145790043/diff/60001/src/
> runtime/proc.c#newcode2203
> src/runtime/proc.c:2203: if(siz >= StackMin - 4*sizeof(uintreg) -
> sizeof(void*))
> please comment what is "4*sizeof(uintreg) - sizeof(void*)"
>
> https://codereview.appspot.com/145790043/
>

[dvyukov, 2014-09-17 00:24:42]

LGTM

[aram, 2014-09-17 05:43:16]

Why does Plan 9 require 4k?

[khr1, 2014-09-17 06:23:37]

Plan 9 reserves 512 bytes of the stack for the note handler.  We add that
to the min size (2K) and round up to a power of 2.
If Plan 9 wants 2K stacks, then it gets only 1.5K of Go frames.


On Tue, Sep 16, 2014 at 10:43 PM, <aram@mgk.ro> wrote:

> Why does Plan 9 require 4k?
>
>
> https://codereview.appspot.com/145790043/
>

[khr, 2014-09-17 15:32:22]

*** Submitted as https://code.google.com/p/go/source/detail?r=2acb59fb63b6 ***

runtime: change minimum stack size to 2K.

It will be 8K on windows because it needs 4K for the OS.
Similarly, plan9 will be 4K.

On linux/amd64, reduces size of 100,000 goroutines
from ~819MB to ~245MB.

Update issue 7514

LGTM=dvyukov
R=golang-codereviews, dvyukov, khr, aram
CC=golang-codereviews
https://codereview.appspot.com/145790043

[aram2, 2014-10-03 13:30:48]

Apologies for the long delay.

On Wed, Sep 17, 2014 at 8:23 AM, 'Keith Randall' via
golang-codereviews <golang-codereviews@googlegroups.com> wrote:
> Plan 9 reserves 512 bytes of the stack for the note handler.

+cc ality, 0intro

Surely we need this only for the M stack?

-- 
Aram Hăvărneanu