Lag after resume culprit found

[Andriy Gapon]

On 17/05/2018 10:56, Andriy Gapon wrote:
> On 17/05/2018 10:46, Johannes Lundberg wrote:
>> On Thu, May 17, 2018 at 7:43 AM, Andriy Gapon <avg at freebsd.org
>> <mailto:avg at freebsd.org>> wrote:
>>
>>     On 17/05/2018 02:07, Johannes Lundberg wrote:
>>     > https://github.com/freebsd/freebsd/commit/66f063557f257baa9c8aeab9f933171eaa6e1cfa
>>     <https://github.com/freebsd/freebsd/commit/66f063557f257baa9c8aeab9f933171eaa6e1cfa>
>>     > x86 cpususpend_handler: call wbinvd after setting suspend state bits
>>
>>     That's very interesting and surprising.
>>     That commit changes something that happens before suspend, it should not have
>>     any effect on the system state after resume.
>>
>>     Does anyone have a theory of what could be wrong?
>>
>> Nope but moving
>>         CPU_CLR_ATOMIC(cpu, &suspended_cpus);
>> back to the end of that scope fixes it.
> 
> That's interesting.
> Thank you for testing it!
> And let me think about it.

Oh, I am stupid.
I intended that operation to be right after the CPU is done with restoring its
saved context.  Which means that it has to be after fpuresume/npxresume block.
Could you please re-test with CPU_CLR_ATOMIC(cpu, &suspended_cpus) at that position?
And my apologies.

>>     > How to test (i915kms)
>>     >
>>     > Start X with glxgears
>>     > Confirm running stable at 60 fps
>>     > suspend/resume (S3)
>>     > glxgears is now fluctuating between 10-40 fps.
> 


-- 
Andriy Gapon