[HN Gopher] New Linux OS Scheduler Reduces Lag by Keeping Light ...
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       New Linux OS Scheduler Reduces Lag by Keeping Light Work on Fewer
       CPU Cores
        
       Author : rbanffy
       Score  : 124 points
       Date   : 2022-09-16 12:26 UTC (10 hours ago)
        
 (HTM) web link (www.tomshardware.com)
 (TXT) w3m dump (www.tomshardware.com)
        
       | Rebelgecko wrote:
       | I wonder how this interacts with big.Little style architectures,
       | like Intel is moving towards with their E cores
        
       | selimnairb wrote:
       | Based on my quick reading of this it doesn't seem like the
       | nesting structure explicitly takes into consideration the
       | presence of efficiency cores. Am I missing something? How would
       | this perform (in terms of latency, throughput, and power
       | efficiency) on a hybrid CPU? Is this only meant for classic SMP
       | and/or NUMA systems?
        
         | alkonaut wrote:
         | It also sounds like it doesn't query the power
         | states/frequencies and instead simply assumes a recently used
         | core will be more efficient to use than idle one?
         | 
         | Is that correct and if so, why? Is it slow or inefficient to
         | query power states at regular intervals? Or would it require
         | more bespoke per-cpu code that you don't want in a scheduler?
         | That type of knowledge seems it's still inevitable to schedule
         | between big/little cores anyway?
        
         | jeffbee wrote:
         | It seems to be focused more on throughput-oriented workloads on
         | large-bordering-on-exotic multi-node servers (e.g. 4-socket
         | Xeons). It doesn't seem to have been evaluated at all in terms
         | of latency (i.e. how long after a network request or other
         | exogenous event arrives is a thread running on the CPU, and is
         | that wakeup CPU selection optimal).
        
       | wing-_-nuts wrote:
       | Interesting. I recently switched from arch to popOS, and one
       | thing that I noticed was that my laptop no longer dropped frames
       | watching 1080p youtube, and the subtitles do a better job keeping
       | up at 2x speed. This is supposedly due to a different scheduler.
       | 
       | Granted, while I've got no hard evidence I'm thermal throttling,
       | I probably need to reapply thermal paste. When I did that for an
       | old laptop my temps dropped by 20c and it noticeably improved
       | it's performance.
        
         | danogentili wrote:
         | You probably didn't install/enable hardware acceleration in
         | arch as described here:
         | https://wiki.archlinux.org/title/Hardware_video_acceleration
        
           | wing-_-nuts wrote:
           | Yeah, I've been using linux for over 20 years, but I was
           | pretty shocked by the number of sharp edges I encountered
           | with arch. A recent update basically borked grub. On
           | investigating the issue I found that the arch maintainers
           | were shipping grub builds from the grub master branch, and
           | when I pointed out this _might_ not be the best idea the
           | maintainer got huffy and said maybe I wasn 't 'ready for
           | arch'.
           | 
           | I installed popOS that day. I miss the AUR a bit, but pop
           | resolves most of the issues I had with ubuntu, and starts and
           | runs noticeably faster than arch, so all in all I'm pretty
           | happy with it. It's a shame that arch can be so user hostile.
           | I really admire it's wiki.
        
             | gmadsen wrote:
             | use manjaro. really, you get the benefits of AUR, stable
             | rolling release, without all the headache of arch
             | 
             | I haven't had a single update issue so far in the last year
        
             | entropicdrifter wrote:
             | Arch is great as a hobby, the problems only come up if you
             | also want to _use_ your computer for other hobbies. I
             | installed arch on my laptop back in 2010 and it was a
             | worthwhile learning experience, but these days I use Mint
             | with the Liquorix kernel and it 's fantastic for regular
             | desktop usage and gaming.
        
             | pkulak wrote:
             | I recently switched from Arch to Fedora Silverblue. I have
             | my terminal open directly into an Archlinux container
             | created by Distrobox. In there I have all my usual bits and
             | bobs installed from the main Arch repos, plus the aur. Even
             | graphical stuff, like Sublime Music, which I export to the
             | host. But you don't need to be running Silverblue. You
             | should give it a shot on PopOS; it really makes you feel at
             | home coming from Arch.
        
               | nerpderp82 wrote:
               | https://github.com/89luca89/distrobox
               | 
               | If done right this could be a baby step towards Qubes,
               | https://www.qubes-os.org/
        
               | pkulak wrote:
               | haha, yeah, I did try out qubes, but I'm not really in it
               | for the security, just the flexibility.
        
             | LordDragonfang wrote:
             | Do you mind listing what issues you have with Ubuntu
             | compared to Arch (and which ones popOS fixes?)? As someone
             | who's only ever used Debian-based distros, I've always
             | wondered what problems Arch actually solves for people.
        
             | rolisz wrote:
             | So I'm not the only one bitten by the Grub issue. I haven't
             | had time to properly look into it so far, and I don't use
             | my ArchLinux machine too often, so I guess it will wait
             | quite a while.
        
               | d_tr wrote:
               | I switched to systemd-boot because I could not boot even
               | after wiping all grub files, reinstalling and running
               | grub-mkconfig. Worked fine in minutes with all my kernel
               | entries and Windows.
               | 
               | Before that I tried rEFInd, wrote a small lean config
               | file and while I could boot, I had some UI issues. Seemed
               | buggy but it might have been my fault.
        
       | eklitzke wrote:
       | Linux Plumbers Conference presentation on this work:
       | https://www.youtube.com/watch?v=_h-kV8AYYqM&t=11097s
       | 
       | Slides:
       | https://lpc.events/event/16/contributions/1198/attachments/9...
        
       | [deleted]
        
       | ChoGGi wrote:
       | The Tom's article references a phoronix article
       | 
       | https://www.phoronix.com/news/Nest-Linux-Scheduling-Warm-Cor...
        
         | btdmaster wrote:
         | The slides are interesting, though I wonder whether the 5%
         | power consumption increase could go away:
         | 
         | https://lpc.events/event/16/contributions/1198/attachments/9...
        
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