Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread David Miller
From: Christian Borntraeger Date: Fri, 21 Oct 2016 17:08:54 +0200 > On 10/21/2016 04:57 PM, David Miller wrote: >> From: Christian Borntraeger >> Date: Fri, 21 Oct 2016 13:58:53 +0200 >> >>> For spinning loops people did often use barrier() or

Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread David Miller
From: Christian Borntraeger Date: Fri, 21 Oct 2016 17:08:54 +0200 > On 10/21/2016 04:57 PM, David Miller wrote: >> From: Christian Borntraeger >> Date: Fri, 21 Oct 2016 13:58:53 +0200 >> >>> For spinning loops people did often use barrier() or cpu_relax(). >>> For most architectures cpu_relax

Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread Christian Borntraeger
On 10/21/2016 04:57 PM, David Miller wrote: > From: Christian Borntraeger > Date: Fri, 21 Oct 2016 13:58:53 +0200 > >> For spinning loops people did often use barrier() or cpu_relax(). >> For most architectures cpu_relax and barrier are the same, but on >> some

Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread Christian Borntraeger
On 10/21/2016 04:57 PM, David Miller wrote: > From: Christian Borntraeger > Date: Fri, 21 Oct 2016 13:58:53 +0200 > >> For spinning loops people did often use barrier() or cpu_relax(). >> For most architectures cpu_relax and barrier are the same, but on >> some architectures cpu_relax can add

Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread David Miller
From: Christian Borntraeger Date: Fri, 21 Oct 2016 13:58:53 +0200 > For spinning loops people did often use barrier() or cpu_relax(). > For most architectures cpu_relax and barrier are the same, but on > some architectures cpu_relax can add some latency. For example on

Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread David Miller
From: Christian Borntraeger Date: Fri, 21 Oct 2016 13:58:53 +0200 > For spinning loops people did often use barrier() or cpu_relax(). > For most architectures cpu_relax and barrier are the same, but on > some architectures cpu_relax can add some latency. For example on s390 > cpu_relax gives up

Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread Peter Zijlstra
On Fri, Oct 21, 2016 at 01:58:53PM +0200, Christian Borntraeger wrote: > Christian Borntraeger (5): > processor.h: introduce cpu_relax_yield > stop_machine: yield CPU during stop machine > s390: make cpu_relax a barrier again > Remove cpu_relax_lowlatency users > remove

Re: [PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread Peter Zijlstra
On Fri, Oct 21, 2016 at 01:58:53PM +0200, Christian Borntraeger wrote: > Christian Borntraeger (5): > processor.h: introduce cpu_relax_yield > stop_machine: yield CPU during stop machine > s390: make cpu_relax a barrier again > Remove cpu_relax_lowlatency users > remove

[PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread Christian Borntraeger
For spinning loops people did often use barrier() or cpu_relax(). For most architectures cpu_relax and barrier are the same, but on some architectures cpu_relax can add some latency. For example on s390 cpu_relax gives up the time slice to the hypervisor. On power cpu_relax tries to give some of

[PATCH/RFC 0/5] cpu_relax: introduce yield, remove lowlatency

2016-10-21 Thread Christian Borntraeger
For spinning loops people did often use barrier() or cpu_relax(). For most architectures cpu_relax and barrier are the same, but on some architectures cpu_relax can add some latency. For example on s390 cpu_relax gives up the time slice to the hypervisor. On power cpu_relax tries to give some of