Re: [ANNOUNCE] BFS CPU scheduler v0.450 with SMT nice support for linux-3.16

Re: [ANNOUNCE] BFS CPU scheduler v0.450 with SMT nice support for linux-3.16

[Hillf Danton]

Hey Con
> 
> This is to announce a resync and  update of the Brain Fuck Scheduler,
> version 0.450 for the latest stable linux kernel.
> 
[...]
> The patch against linux-3.16(.x) is available here:
> http://ck.kolivas.org/patches/bfs/3.0/3.16/3.16-sched-bfs-450.patch
> 
$ grep -nr above_background_load  bfs/src
bfs/src/3.16-sched-bfs-450.patch:689:+bool above_background_load(void);
bfs/src/3.16-sched-bfs-450.patch:736:+static inline bool above_background_load(void)
bfs/src/3.16-sched-bfs-450.patch:1665:+bool above_background_load(void)

Would you please pin-point what is that routine used for?

Thanks
Hillf

Re: [ANNOUNCE] BFS CPU scheduler v0.450 with SMT nice support for linux-3.16

[Con Kolivas]

On 3 December 2014 at 19:12, Hillf Danton <hillf.zj@alibaba-inc.com> wrote:
> Hey Con

Hi Hilf

>> This is to announce a resync and  update of the Brain Fuck Scheduler,
>> version 0.450 for the latest stable linux kernel.
>>
> [...]
>> The patch against linux-3.16(.x) is available here:
>> http://ck.kolivas.org/patches/bfs/3.0/3.16/3.16-sched-bfs-450.patch
>>
> $ grep -nr above_background_load  bfs/src
> bfs/src/3.16-sched-bfs-450.patch:689:+bool above_background_load(void);
> bfs/src/3.16-sched-bfs-450.patch:736:+static inline bool above_background_load(void)
> bfs/src/3.16-sched-bfs-450.patch:1665:+bool above_background_load(void)
>
> Would you please pin-point what is that routine used for?

This function used to be used with the VM tweaks that the -ck patchset
used to come with. I have since deprecated those VM tweaks but the
function remains in the scheduler. You're right to point it out and
I'll remove it when I resync with 3.18 (it's still in the BFS 458
patch for 3.17).

Thanks,
Con

> Thanks
> Hillf
>

[ANNOUNCE] BFS CPU scheduler v0.450 with SMT nice support for linux-3.16

[Con Kolivas]

This is to announce a resync and  update of the Brain Fuck Scheduler, 
version 0.450 for the latest stable linux kernel.

In addition to the usual round of fixes and changes to resync with mainline 
changes, this release brings a new feature of configurable SMT nice support.

The configuration help follows to explain:

Enabling Hyperthreading on Intel CPUs decreases the effectiveness                                                                                   
of the use of 'nice' levels and different scheduling policies                                                                                       
(e.g. realtime) due to sharing of CPU power between hyperthreads.                                                                                   
SMT nice support makes each logical CPU aware of what is running on                                                                                 
its hyperthread siblings, maintaining appropriate distribution of                                                                                   
CPU according to nice levels and scheduling policies at the expense                                                                                 
of slightly increased overhead.      

This code is based on my original idea from ten years ago discussed here:
http://lwn.net/Articles/73614/

A full discussion of the rationale and development follows here:
http://ck-hack.blogspot.com/2014/08/smthyperthreading-nice-and-scheduling.html

The patch against linux-3.16(.x) is available here:
http://ck.kolivas.org/patches/bfs/3.0/3.16/3.16-sched-bfs-450.patch

A -ck branded linux-3.16-ck1 patch is available here:
http://ck.kolivas.org/patches/3.0/3.16/3.16-ck1/

All patches available here:
http://ck.kolivas.org/patches

Code blog:
http://ck-hack.blogspot.com

Enjoy!
お楽しみください

-- 
-ck