8 Feb
2011
8 Feb
'11
11:22 p.m.
LS,
Does mounting /tmp to tmpfs really yield a tangible performance gain
when it comes to setting up a real-time low latency environment?
Best,
Jeremy
8 Feb
8 Feb
11:45 p.m.
On Tue, Feb 8, 2011 at 5:22 PM, Jeremy Jongepier <jeremy(a)autostatic.com> wrote:
LS,
Does mounting /tmp to tmpfs really yield a tangible performance gain when it
comes to setting up a real-time low latency environment?
no, but putting JACK's tmpdir on a tmpfs filesystem does.
current versions of JACK use /dev/shm as the location for this, no
/tmp (this was done years ago).
--p
9 Feb
9 Feb
9:37 a.m.
On 02/08/2011 11:45 PM, Paul Davis wrote:
no, but putting JACK's tmpdir on a tmpfs
filesystem does.
current versions of JACK use /dev/shm as the location for this, no
/tmp (this was done years ago).
--p
Thanks for the reply Paul. But what about other applications that use
/tmp? Could they benefit from a /tmp directory mounted on a tmpfs
filesystem?
Best,
Jeremy
9:44 a.m.
----- "Jeremy Jongepier" <jeremy(a)autostatic.com> wrote:
Thanks for the reply Paul. But what about other
applications that use
/tmp? Could they benefit from a /tmp directory mounted on a tmpfs
filesystem?
no access to disk, so you may win.
On the other hand you squat some RAM for a file system,
so you may end up with swapping anyway.
So answer is: it depends. On what you do. On your computer
(amount of RAM).
You clearly win if the programs you run do a lot of little I/O
in /tmp and don't smoke too much memory for other things.
10:04 a.m.
On 02/09/2011 09:44 AM, Cedric Roux wrote:
no access to disk, so you may win.
On the other hand you squat some RAM for a file system,
so you may end up with swapping anyway.
Thanks Cedric, I was thinking about that too. And since swapping is not
so desirable in such an environment you can lower the swappiness. But I
guess that may conflict again with your /tmp being on a temporary
filesystem.
So answer is: it depends. On what you do. On your
computer
(amount of RAM).
You clearly win if the programs you run do a lot of little I/O
in /tmp and don't smoke too much memory for other things.
Actually I have no idea what the programs I run do in /tmp. And given
the fact that apparently some people had more issues (xruns) with the
default swappiness of many systems than with a /tmp on a physical disk
I'd assume not mounting /tmp to tmpfs would be a better option. Unless
you got like 16Gb of RAM. Which I don't have.
Best,
Jeremy
12:56 p.m.
On Wed, Feb 9, 2011 at 3:37 AM, Jeremy Jongepier <jeremy(a)autostatic.com> wrote:
On 02/08/2011 11:45 PM, Paul Davis wrote:
programs that use the filesystem from a realtime audio thread are
incorrectly written.
a system that allows disk i/o to interfere with a realtime audio
thread is badly configured.
ergo, i would conclude that the only realtime audio programs that can
benefit from this sort of thing are either badly written or running on
a misconfigured system.
JACK itself isn't doing any file I/O - it just happens to use an
inter-process communication system that uses identifiers that are
related to the filesystem.
no, but putting JACK's tmpdir on a tmpfs
filesystem does.
current versions of JACK use /dev/shm as the location for this, no
/tmp (this was done years ago).
--p
Thanks for the reply Paul. But what about other applications that use
/tmp? Could they benefit from a /tmp directory mounted on a tmpfs
filesystem? 
1:53 p.m.
On Wed, Feb 09, 2011 at 06:56:19AM -0500, Paul Davis wrote:
On Wed, Feb 9, 2011 at 3:37 AM, Jeremy Jongepier
<jeremy(a)autostatic.com> wrote:
you should check the jack README... iirc it still talks about this /tmp
stuff.
On 02/08/2011 11:45 PM, Paul Davis wrote:
programs that use the filesystem from a realtime audio thread are
incorrectly written.
a system that allows disk i/o to interfere with a realtime audio
thread is badly configured.
ergo, i would conclude that the only realtime audio programs that can
benefit from this sort of thing are either badly written or running on
a misconfigured system.
JACK itself isn't doing any file I/O - it just happens to use an
inter-process communication system that uses identifiers that are
related to the filesystem. no, but putting JACK's tmpdir on a tmpfs
filesystem does.
current versions of JACK use /dev/shm as the location for this, no
/tmp (this was done years ago).
--p
Thanks for the reply Paul. But what about other applications that use
/tmp? Could they benefit from a /tmp directory mounted on a tmpfs
filesystem? _______________________________________________
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6 comments
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participants (4)
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