Showing posts with label sched_yield. Show all posts
Showing posts with label sched_yield. Show all posts

Monday, 12 December 2016

linux-4.9-ck1, MuQSS version 0.150

Announcing a new -ck release, 4.9-ck1  with new version of the Multiple Queue Skiplist Scheduler, version 0.150. These are patches designed to improve system responsiveness and interactivity with specific emphasis on the desktop, but configurable for any workload.

linux-4.9-ck1

-ck1 patches:
http://ck.kolivas.org/patches/4.0/4.9/4.9-ck1/

Git tree:
https://github.com/ckolivas/linux/tree/4.9-ck

Ubuntu 16.04 LTS packages:
http://ck.kolivas.org/patches/4.0/4.9/4.9-ck1/Ubuntu16.04/

MuQSS

Download:
4.9-sched-MuQSS_150.patch

Git tree:
4.9-muqss


MuQSS 0.150 updates

Regarding MuQSS, apart from a resync to linux-4.9, which has numerous hotplug and cpufreq changes (again!), I've cleaned up the patch to not include any Hz changes of its own, leaving Hz changes up to users to choose, unless they use the -ck patchset.
Additionally, I've modified sched_yield yet again. Since expected behaviour is different for different (inappropriate) users out there of sched_yield, I've made it tunable in /proc/sys/kernel/yield_type and changed the default to what I believe should happen. From the documentation I added in Documentation/sysctl/kernel.txt:

yield_type: (MuQSS CPU scheduler only)

This determines what type of yield calls to sched_yield will perform.

 0: No yield.
 1: Yield only to better priority/deadline tasks. (default)
 2: Expire timeslice and recalculate deadline.

Previous versions of MuQSS defaulted to type 2 above. If you find behavioural regressions with any of your workloads try switching it back to 2.

4.9-ck1 updates

Apart from resyncing with the latest trees from linux-bfq and wb-buf-throttling
- Added a new kernel configuration option to enable threaded IRQs and set it by default
- Changed Hz to default to the safe 100 value, removing 128 which caused spurious issues and had no real world advantage.
- Fixed a build for muqss disabled (why would you use -ck and do that I don't know)
- Made hrtimers not be used if we know we're in suspend which may have caused suspend failures for drivers that did no use correct freezable vs normal timeouts
- Enabled bfq and set it to default
- Enabled writeback throttling by default

Enjoy!
お楽しみ下さい
-ck