5 ms·

It's a great idea - is there any word as to whether it's patented/patentable, or might we see this on other OSes?

sirn 13y ago
Not sure about other features, but for Compressed Memory, there's zRam[1] in Linux that does something similiar if not the same thing. [1]: http://en.wikipedia.org/wiki/ZRam http://en.wikipedia.org/wiki/ZRam
- AhtiK 13y ago
  zram in Linux kernel should be quite close to what the advertised "Compressed Memory" feature is in Mavericks. AFAIK zram is using LZO compression. According to some tests it is about the same efficiency as WKdm (used in Mavericks) but it has bit slower compression speed [1]. zram is an experimental kernel module since 3.2 and can be installed: [2], [3], [4]. [1] WKdm vs LZO http://terpconnect.umd.edu/~barua/matt-compress-tr.pdf http://terpconnect.umd.edu/~barua/matt-compress-tr.pdf [2] Gentoo zram http://wiki.gentoo.org/wiki/Zram http://wiki.gentoo.org/wiki/Zram [3] Arch zram https://wiki.archlinux.org/index.php/Maximizing_Performance https://wiki.archlinux.org/index.php/Maximizing_Performance [4] Debian&Ubuntu zram http://gionn.net/2012/03/11/zram-on-debian-ubuntu-for-memory-overcommitment/ http://gionn.net/2012/03/11/zram-on-debian-ubuntu-for-memory...
  - morsch 13y ago
    Ok so zram creates a compressed block device in memory. Apparently it's sometimes used to hold a swap space for virtual memory. Compression rates are about 50%, ie you can roughly "double" your memory. I was going to say that this is crazy: why waste RAM to hold swap space, when you could use that RAM to avoid swapping in the first place. I still think it'd be odd to reserve a significant chunk of your memory for it. But I can see how it'd be pretty cool if you can manage it dynamically, ie. only start compressing memory as you run out of it to avoid hitting the disk. Of course the usual rule still applies: if your PC swaps often, get more RAM; or if the RAM is not upgradable, go back in time and buy a machine with more RAM, then smack yourself on the head for not doing so in the first place. :)
    - diroussel 13y ago
      > I was going to say that this is crazy: why waste RAM to hold swap space Because you can get faster performance, and more importantly lower energy usage, on the same hardware.
  - deno 13y ago
    Also https://github.com/mystilleef/FedoraZram https://github.com/mystilleef/FedoraZram Note that you need kmod–staging from RPMFusion.
- sciurus 13y ago
  FYI there are a couple other implementations of this, with zswap looking like the closest to being merged into mainline linux. https://lwn.net/Articles/551401/ https://lwn.net/Articles/551401/ https://lwn.net/Articles/545244/ https://lwn.net/Articles/545244/
cheald 13y ago
Timer coalescing has been around for ages. Linux and Windows both already do it. Here's a 2009 article describing it in Windows: https://blogs.technet.com/b/askperf/archive/2009/10/03/windows-7-windows-server-2008-r2-core-parking-intelligent-timer-tick-timer-coalescing.aspx?Redirected=true https://blogs.technet.com/b/askperf/archive/2009/10/03/windo... "App Nap" is a familiar concept to anyone who has ever played a game with unfocused framerate caps (like most MMOs, for example). It being enforced by the OS may be new, though. It kind of feels like a more aggressive `nice` though.
- ttrreeww 13y ago
  I bet Apple filed patents for App Nap already.
- melchebo 13y ago
  Apple had timer deadlines (much the same thing) in the kernel since the 10.5.5 release for their then new MacBook Airs, in November 2008.

sirn 13y ago

Not sure about other features, but for Compressed Memory, there's zRam[1] in Linux that does something similiar if not the same thing. [1]: http://en.wikipedia.org/wiki/ZRam http://en.wikipedia.org/wiki/ZRam

AhtiK 13y ago
zram in Linux kernel should be quite close to what the advertised "Compressed Memory" feature is in Mavericks. AFAIK zram is using LZO compression. According to some tests it is about the same efficiency as WKdm (used in Mavericks) but it has bit slower compression speed [1]. zram is an experimental kernel module since 3.2 and can be installed: [2], [3], [4]. [1] WKdm vs LZO http://terpconnect.umd.edu/~barua/matt-compress-tr.pdf http://terpconnect.umd.edu/~barua/matt-compress-tr.pdf [2] Gentoo zram http://wiki.gentoo.org/wiki/Zram http://wiki.gentoo.org/wiki/Zram [3] Arch zram https://wiki.archlinux.org/index.php/Maximizing_Performance https://wiki.archlinux.org/index.php/Maximizing_Performance [4] Debian&Ubuntu zram http://gionn.net/2012/03/11/zram-on-debian-ubuntu-for-memory-overcommitment/ http://gionn.net/2012/03/11/zram-on-debian-ubuntu-for-memory...
- morsch 13y ago
  Ok so zram creates a compressed block device in memory. Apparently it's sometimes used to hold a swap space for virtual memory. Compression rates are about 50%, ie you can roughly "double" your memory. I was going to say that this is crazy: why waste RAM to hold swap space, when you could use that RAM to avoid swapping in the first place. I still think it'd be odd to reserve a significant chunk of your memory for it. But I can see how it'd be pretty cool if you can manage it dynamically, ie. only start compressing memory as you run out of it to avoid hitting the disk. Of course the usual rule still applies: if your PC swaps often, get more RAM; or if the RAM is not upgradable, go back in time and buy a machine with more RAM, then smack yourself on the head for not doing so in the first place. :)
  - diroussel 13y ago
    > I was going to say that this is crazy: why waste RAM to hold swap space Because you can get faster performance, and more importantly lower energy usage, on the same hardware.
- deno 13y ago
  Also https://github.com/mystilleef/FedoraZram https://github.com/mystilleef/FedoraZram Note that you need kmod–staging from RPMFusion.
sciurus 13y ago
FYI there are a couple other implementations of this, with zswap looking like the closest to being merged into mainline linux. https://lwn.net/Articles/551401/ https://lwn.net/Articles/551401/ https://lwn.net/Articles/545244/ https://lwn.net/Articles/545244/

cheald 13y ago

Timer coalescing has been around for ages. Linux and Windows both already do it. Here's a 2009 article describing it in Windows: https://blogs.technet.com/b/askperf/archive/2009/10/03/windows-7-windows-server-2008-r2-core-parking-intelligent-timer-tick-timer-coalescing.aspx?Redirected=true https://blogs.technet.com/b/askperf/archive/2009/10/03/windo... "App Nap" is a familiar concept to anyone who has ever played a game with unfocused framerate caps (like most MMOs, for example). It being enforced by the OS may be new, though. It kind of feels like a more aggressive `nice` though.

ttrreeww 13y ago
I bet Apple filed patents for App Nap already.
melchebo 13y ago
Apple had timer deadlines (much the same thing) in the kernel since the 10.5.5 release for their then new MacBook Airs, in November 2008.