Re: [Discussion v2] Usecases for the per-task latency-nice attribute

2019-10-07 Thread Tim Chen
On 10/2/19 9:11 AM, David Laight wrote: > From: Parth Shah >> Sent: 30 September 2019 11:44 > ... >> 5> Separating AVX512 tasks and latency sensitive tasks on separate cores >> ( -Tim Chen ) >> === >> Another usecase we are

Re: [Discussion v2] Usecases for the per-task latency-nice attribute

2019-10-07 Thread Parth Shah
On 10/2/19 9:41 PM, David Laight wrote: > From: Parth Shah >> Sent: 30 September 2019 11:44 > ... >> 5> Separating AVX512 tasks and latency sensitive tasks on separate cores >> ( -Tim Chen ) >> === >> Another usecase we are

RE: [Discussion v2] Usecases for the per-task latency-nice attribute

2019-10-02 Thread David Laight
From: Parth Shah > Sent: 30 September 2019 11:44 ... > 5> Separating AVX512 tasks and latency sensitive tasks on separate cores > ( -Tim Chen ) > === > Another usecase we are considering is to segregate those workload that

[Discussion v2] Usecases for the per-task latency-nice attribute

2019-09-30 Thread Parth Shah
Hello everyone, This is the v2 of the discussion started for introducing per-task latency-nice attribute for providing scheduler hints. v1: https://lkml.org/lkml/2019/9/18/555 In brief, we face two challenges with the introduction of such attr. 1. Name: == ( Should be relevant to

Re: Usecases for the per-task latency-nice attribute

2019-09-27 Thread Pavel Machek
Hi! > > I don't want to start a bikeshedding session here, but I agree with Parth > > on the interpretation of the values. > > > > I've always read niceness values as > > -20 (least nice to the system / other processes) > > +19 (most nice to the system / other processes) > > > > So following

Re: Usecases for the per-task latency-nice attribute

2019-09-20 Thread Parth Shah
On 9/19/19 8:13 PM, Qais Yousef wrote: > On 09/18/19 18:11, Parth Shah wrote: >> Hello everyone, >> >> As per the discussion in LPC2019, new per-task property like latency-nice >> can be useful in certain scenarios. The scheduler can take proper decision >> by knowing latency requirement of a

Re: Usecases for the per-task latency-nice attribute

2019-09-19 Thread Valentin Schneider
On 19/09/2019 17:41, Parth Shah wrote: > So jotting down separately, in case if we think to have "latency-nice" > terminology, then we might need to select one of the 2 interpretation: > > 1). >> -20 (least nice to latency, i.e. sacrifice latency for throughput) >> +19 (most nice to latency, i.e.

Re: Usecases for the per-task latency-nice attribute

2019-09-19 Thread Parth Shah
On 9/18/19 9:12 PM, Valentin Schneider wrote: > On 18/09/2019 15:18, Patrick Bellasi wrote: >>> 1. Name: What should be the name for such attr for all the possible >>> usecases? >>> = >>> Latency nice is the proposed name as of now where the lower value indicates >>> that the task

Re: Usecases for the per-task latency-nice attribute

2019-09-19 Thread Tim Chen
On 9/19/19 2:06 AM, David Laight wrote: > From: Tim Chen >> Sent: 18 September 2019 18:16 > ... >> Some users are running machine learning batch tasks with AVX512, and have >> observed >> that these tasks affect the tasks needing a fast response. They have to >> rely on manual CPU affinity to

Re: Usecases for the per-task latency-nice attribute

2019-09-19 Thread Tim Chen
On 9/19/19 1:37 AM, Parth Shah wrote: > >> >> $> Separating AVX512 tasks and latency sensitive tasks on separate cores >> - >> Another usecase we are considering is to segregate those workload that will >> pull down >> core

Re: Usecases for the per-task latency-nice attribute

2019-09-19 Thread Qais Yousef
On 09/18/19 18:11, Parth Shah wrote: > Hello everyone, > > As per the discussion in LPC2019, new per-task property like latency-nice > can be useful in certain scenarios. The scheduler can take proper decision > by knowing latency requirement of a task from the end-user itself. > > There has

RE: Usecases for the per-task latency-nice attribute

2019-09-19 Thread David Laight
From: Tim Chen > Sent: 18 September 2019 18:16 ... > Some users are running machine learning batch tasks with AVX512, and have > observed > that these tasks affect the tasks needing a fast response. They have to > rely on manual CPU affinity to separate these tasks. With appropriate > latency

Re: Usecases for the per-task latency-nice attribute

2019-09-19 Thread Parth Shah
On 9/18/19 10:46 PM, Tim Chen wrote: > On 9/18/19 5:41 AM, Parth Shah wrote: >> Hello everyone, >> >> As per the discussion in LPC2019, new per-task property like latency-nice >> can be useful in certain scenarios. The scheduler can take proper decision >> by knowing latency requirement of a

Re: Usecases for the per-task latency-nice attribute

2019-09-19 Thread Parth Shah
On 9/18/19 7:48 PM, Patrick Bellasi wrote: > > On Wed, Sep 18, 2019 at 13:41:04 +0100, Parth Shah wrote... > >> Hello everyone, > > Hi Parth, > thanks for staring this discussion. > > [ + patrick.bell...@matbug.net ] my new email address, since with > @arm.com I will not be reachable

Re: Usecases for the per-task latency-nice attribute

2019-09-18 Thread Tim Chen
On 9/18/19 5:41 AM, Parth Shah wrote: > Hello everyone, > > As per the discussion in LPC2019, new per-task property like latency-nice > can be useful in certain scenarios. The scheduler can take proper decision > by knowing latency requirement of a task from the end-user itself. > > There has

Re: Usecases for the per-task latency-nice attribute

2019-09-18 Thread Vincent Guittot
On Wed, 18 Sep 2019 at 17:46, Patrick Bellasi wrote: > > > On Wed, Sep 18, 2019 at 16:22:32 +0100, Vincent Guittot wrote... > > > On Wed, 18 Sep 2019 at 16:19, Patrick Bellasi > > wrote: > > [...] > > >> $> Wakeup path tunings > >> == > >> > >> Some additional possible

Re: Usecases for the per-task latency-nice attribute

2019-09-18 Thread Patrick Bellasi
On Wed, Sep 18, 2019 at 16:22:32 +0100, Vincent Guittot wrote... > On Wed, 18 Sep 2019 at 16:19, Patrick Bellasi wrote: [...] >> $> Wakeup path tunings >> == >> >> Some additional possible use-cases was already discussed in [3]: >> >> - dynamically tune the policy of

Re: Usecases for the per-task latency-nice attribute

2019-09-18 Thread Valentin Schneider
On 18/09/2019 15:18, Patrick Bellasi wrote: >> 1. Name: What should be the name for such attr for all the possible usecases? >> = >> Latency nice is the proposed name as of now where the lower value indicates >> that the task doesn't care much for the latency > > If by "lower value"

Re: Usecases for the per-task latency-nice attribute

2019-09-18 Thread Vincent Guittot
On Wed, 18 Sep 2019 at 16:19, Patrick Bellasi wrote: > > > On Wed, Sep 18, 2019 at 13:41:04 +0100, Parth Shah wrote... > > > Hello everyone, > > Hi Parth, > thanks for staring this discussion. > > [ + patrick.bell...@matbug.net ] my new email address, since with > @arm.com I will not be reachable

Re: Usecases for the per-task latency-nice attribute

2019-09-18 Thread Patrick Bellasi
On Wed, Sep 18, 2019 at 13:41:04 +0100, Parth Shah wrote... > Hello everyone, Hi Parth, thanks for staring this discussion. [ + patrick.bell...@matbug.net ] my new email address, since with @arm.com I will not be reachable anymore starting next week. > As per the discussion in LPC2019, new

Usecases for the per-task latency-nice attribute

2019-09-18 Thread Parth Shah
Hello everyone, As per the discussion in LPC2019, new per-task property like latency-nice can be useful in certain scenarios. The scheduler can take proper decision by knowing latency requirement of a task from the end-user itself. There has already been an effort from Subhra for introducing