6 ms·

Linux resource scheduling and prioritization and is pretty awful compared to its popularity. TBH, there are very few OSes that get high-pressure resource sched

Linux resource scheduling and prioritization and is pretty awful compared to its popularity. TBH, there are very few OSes that get high-pressure resource scheduling and prioritization right under nearly all normal circumstances. The hackaround for decades on Linux is always adding a tiny swap device, say 64-256 MiB on a fast device in order to 0) detect average high memory pressure with monitoring tools 1) prevent oddities under load without swap (as in OP example).

ddingus 7y ago
Sgi IRIX nailed this, FWIW. I would have thought some of the IRIX scheduler made it into Linux by now.
- Annatar 7y ago
  No way, any sufficiently advanced technology is indistinguishable from magic and IRIX was so very, very advanced. IRIX hasn't been in development for almost two decades now and it's still more advanced in aspects like guaranteed I/O and software management (inst(1M))... What does that say about it and what does it say about the engineers who worked on it?
  - twic 7y ago
    XFS is still better than any version of that ext dreck!
    - vthriller 7y ago
      That's debatable. Better at losing file contents after hard reset? Maybe.
  - ddingus 7y ago
    Makes me want to gather them in a room and continue the process. Irix was so very good.
  - ddingus 7y ago
    And you are right on all counts. Inst was magic. The things I did, often on live systems...
- IcePic 7y ago
  Irix even had "virtual swap" which had no (or very insufficient sized) backing store for it, just to handle all the superlarge allocations from which it only uses a tiny amount.
nathell 7y ago
As crazy as it sounds, can that fast device be a ramdisk?
- GuB-42 7y ago
  Exactly what I thought. Losing <5% of your RAM as swap space probably won't do much difference. But if it solves problems, why doesn't the kernel automatically assign part of RAM as a virtual swap device, if the user allows it. It can help monitoring tools, and because the kernel knows it is not a real swap device, it can optimize its use.
- LargoLasskhyfv 7y ago
  Not crazy at all, very useful. https://en.wikipedia.org/wiki/Zram https://en.wikipedia.org/wiki/Zram https://wiki.gentoo.org/wiki/Zram https://wiki.gentoo.org/wiki/Zram https://wiki.debian.org/ZRam https://wiki.debian.org/ZRam Or Armbian, a Debian derivative for many RaspberryPi-like ARM boards, where it helps avoiding trashing the usual sd-cards, and holds the logs, with different compression algorithms for /var/log, /tmp and swap. Their script is here: https://github.com/armbian/build/blob/master/packages/bsp/common/usr/lib/armbian/armbian-zram-config https://github.com/armbian/build/blob/master/packages/bsp/co... I really like how this enables a tiny NanoPi Neo2 with one GB Ram booting from a 64GB SD-Card in an aluminum case with SATA-adapter and a 2,5" HDD mostly idling to draw only about 1W from the wall socket, while clocking up from about 400Mhz to 1,3Ghz if it needs to. It's not the fastest, but sufficient.
- pantalaimon 7y ago
  It's not that crazy, there is zram: https://www.kernel.org/doc/Documentation/blockdev/zram.txt https://www.kernel.org/doc/Documentation/blockdev/zram.txt

ddingus 7y ago

Sgi IRIX nailed this, FWIW. I would have thought some of the IRIX scheduler made it into Linux by now.

Annatar 7y ago
No way, any sufficiently advanced technology is indistinguishable from magic and IRIX was so very, very advanced. IRIX hasn't been in development for almost two decades now and it's still more advanced in aspects like guaranteed I/O and software management (inst(1M))... What does that say about it and what does it say about the engineers who worked on it?
- twic 7y ago
  XFS is still better than any version of that ext dreck!
  - vthriller 7y ago
    That's debatable. Better at losing file contents after hard reset? Maybe.
- ddingus 7y ago
  Makes me want to gather them in a room and continue the process. Irix was so very good.
- ddingus 7y ago
  And you are right on all counts. Inst was magic. The things I did, often on live systems...
IcePic 7y ago
Irix even had "virtual swap" which had no (or very insufficient sized) backing store for it, just to handle all the superlarge allocations from which it only uses a tiny amount.

nathell 7y ago

As crazy as it sounds, can that fast device be a ramdisk?

GuB-42 7y ago
Exactly what I thought. Losing <5% of your RAM as swap space probably won't do much difference. But if it solves problems, why doesn't the kernel automatically assign part of RAM as a virtual swap device, if the user allows it. It can help monitoring tools, and because the kernel knows it is not a real swap device, it can optimize its use.
LargoLasskhyfv 7y ago
Not crazy at all, very useful. https://en.wikipedia.org/wiki/Zram https://en.wikipedia.org/wiki/Zram https://wiki.gentoo.org/wiki/Zram https://wiki.gentoo.org/wiki/Zram https://wiki.debian.org/ZRam https://wiki.debian.org/ZRam Or Armbian, a Debian derivative for many RaspberryPi-like ARM boards, where it helps avoiding trashing the usual sd-cards, and holds the logs, with different compression algorithms for /var/log, /tmp and swap. Their script is here: https://github.com/armbian/build/blob/master/packages/bsp/common/usr/lib/armbian/armbian-zram-config https://github.com/armbian/build/blob/master/packages/bsp/co... I really like how this enables a tiny NanoPi Neo2 with one GB Ram booting from a 64GB SD-Card in an aluminum case with SATA-adapter and a 2,5" HDD mostly idling to draw only about 1W from the wall socket, while clocking up from about 400Mhz to 1,3Ghz if it needs to. It's not the fastest, but sufficient.
pantalaimon 7y ago
It's not that crazy, there is zram: https://www.kernel.org/doc/Documentation/blockdev/zram.txt https://www.kernel.org/doc/Documentation/blockdev/zram.txt