LinuxMusicians

Thanks, I downloaded the new version.

noedig wrote:

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lowlatency.linuxaudio.org      Linux Audio Low-Latency Performance How-To

lilith@realTimeConfigQuickScan wrote:

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** Warning: no tmpfs partition mounted on /tmp
   For more information, see:
   - http://wiki.linuxaudio.org/wiki/system_configuration#tmpfs
   - http://lowlatency.linuxaudio.org

So the lowlatency.linuxaudio homepage had dealt with the "tmpfs" / "shm" topic?

khz wrote:

noedig wrote:

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lowlatency.linuxaudio.org      Linux Audio Low-Latency Performance How-To

lilith@realTimeConfigQuickScan wrote:

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** Warning: no tmpfs partition mounted on /tmp
   For more information, see:
   - http://wiki.linuxaudio.org/wiki/system_configuration#tmpfs
   - http://lowlatency.linuxaudio.org

So the lowlatency.linuxaudio homepage had dealt with the "tmpfs" / "shm" topic?

I got the same warning with the old version.

As far as I remember you had both entries ("shm/tmpfs") in /etc/fstab and later removed the "tmpfs" entry.
If so: Logical because the script searches for "tmpfs" and you only entered "shm".
Only adding the "shm" entry is correct . According to jack Homepage jack uses "shm".

khz wrote:As far as I remember you had both entries ("shm/tmpfs") in /etc/fstab and later removed the "tmpfs" entry.
If so: Logical because the script searches for "tmpfs" and you only entered "shm".
Only adding the "shm" entry is correct . According to jack Homepage jack uses "shm".

Exactly, so this needs to be changed in the script

If what I wrote is true. I have found very little in the intenet on this subject. That surprises me.
I don't have any current links on this topic and of us audio users we are the only two who may have entered this entry in the fstab?
EDIT: Added "size=7500M" to shm.

lilith wrote:

khz wrote:As far as I remember you had both entries ("shm/tmpfs") in /etc/fstab and later removed the "tmpfs" entry.
If so: Logical because the script searches for "tmpfs" and you only entered "shm".
Only adding the "shm" entry is correct . According to jack Homepage jack uses "shm".

Exactly, so this needs to be changed in the script

What exactly do you think should be changed in the script? Could you propose a PR?

viewtopic.php?p=93108#p93108?

khz suggested to add the size of the RAM in the shm line in fstab:
I forgot the M after 7500 and the result was that Jack didn't start, even Chromium and Firefox didn't start. There where some IO errors shown. After adding the M all is working fine again. Crazy how this affects things.

FWIW & IIRC /dev/shm defaults to half of your ram as do the other tmpfs that you have mounted. Changing this is probably mostly useful if you want to limit how much an app can use, not that I've ever seen one actually using much at all. If you don't need to either make it smaller nor bigger then it's probably easier to leave it out of fstab altogether..

Jack Winter wrote:FWIW & IIRC /dev/shm defaults to half of your ram as do the other tmpfs that you have mounted. Changing this is probably mostly useful if you want to limit how much an app can use, not that I've ever seen one actually using much at all. If you don't need to either make it smaller nor bigger then it's probably easier to leave it out of fstab altogether..

Thanks, I'll change it to 4000M then. When I looked very little was used always.

e.g. now:

tmpfs 7,4G 188M 7,2G 3% /dev/shm

BTW: When is it used or what are the criteria when shm is used and when normal RAM?

JACK uses it by default and it was added as a config option for the kernel back in 2.x.

IIRC, back then JACK used /tmp, but was changed to use /dev/shm when that became a standard feature of the kernel. IMO there really isn't any reason at all to bother with this, unless you really are paranoid and would want to make sure that no malicious application starves you of RAM, but if so then you really ought to do the same with all your tmpfs mounts too..

I have "size" in the fstab to define the maximum RAM usage. The gcc can also occupy 512 GB RAM. I'm wondering if internet RAM wouldn't be the better solution https://www.cs.swarthmore.edu/~newhall/nswap2L.html.

I'll take it out completely. As stated somewhere else this is also better for SSD on the long-term.

Jack Winter wrote:JACK uses it by default and it was added as a config option for the kernel back in 2.x.

IIRC, back then JACK used /tmp, but was changed to use /dev/shm when that became a standard feature of the kernel. IMO there really isn't any reason at all to bother with this, unless you really are paranoid and would want to make sure that no malicious application starves you of RAM, but if so then you really ought to do the same with all your tmpfs mounts too..

If I don't have any entry in fstab it is still used as it is in the kernel by default? Can this be checked somehow?