code review 11433045: runtime: re-enable preemption

runtime: re-enable preemption

Update issue 543

I believe the runtime is strong enough now to reenable
preemption during the function prologue.
Assuming this is or can be made stable, it will be in Go 1.2.
More aggressive preemption is not planned for Go 1.2.

[rsc, 2013-07-17 16:54:19]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://code.google.com/p/go/

[iant, 2013-07-17 18:02:36]

LGTM

[rsc, 2013-07-17 18:03:30]

*** Submitted as https://code.google.com/p/go/source/detail?r=c242bbf5fa8c ***

runtime: re-enable preemption

Update issue 543

I believe the runtime is strong enough now to reenable
preemption during the function prologue.
Assuming this is or can be made stable, it will be in Go 1.2.
More aggressive preemption is not planned for Go 1.2.

R=golang-dev, iant
CC=golang-dev
https://codereview.appspot.com/11433045

[dvyukov, 2013-07-18 13:58:29]

> More aggressive preemption is not planned for Go 1.2.

Do you mean preemption of long running goroutines?
What is the reason? Bug-wise it is the same as GC preemption, and will shake out
bugs faster.
Or do you mean that we are just moving too fast?

[rsc, 2013-07-18 14:07:09]

On Thu, Jul 18, 2013 at 9:58 AM, <dvyukov@google.com> wrote:

> More aggressive preemption is not planned for Go 1.2.
>>
>
> Do you mean preemption of long running goroutines?
>

I mean preemption of goroutines anywhere other than at function entry.
For example, preemption on backwards branches is not going to be in Go 1.2.

Russ

[dvyukov, 2013-07-18 14:19:18]

On Thu, Jul 18, 2013 at 6:07 PM, Russ Cox <rsc@golang.org> wrote:
> On Thu, Jul 18, 2013 at 9:58 AM, <dvyukov@google.com> wrote:
>>>
>>> More aggressive preemption is not planned for Go 1.2.
>>
>>
>> Do you mean preemption of long running goroutines?
>
>
> I mean preemption of goroutines anywhere other than at function entry.
> For example, preemption on backwards branches is not going to be in Go 1.2.

Ah, OK.