[linux-audio-user] hello gentoo? speed up please...

[Reuben Martin]

Back on Sunday 10 April 2005 03:25 pm, Aaron Trumm was like:
> hello all - got a question - I've only recently been stopping and taking a
> look at my studio computer's performance and in the almost year since I
> change from Red Hat 9 to gentoo, it's been more solid on some things, but I
> notice a huge latency difference - ie: I have to run Jack at -p 8192 to get
> anything done in Ardour
>
> Anybody have any tips on what to look at to tweak it?  Seems like it should
> do better than that... I didn't see it as a problem until in the last few
> days I started playing with playing softsynths live directly into Ardour -
> you've gotta be running at -p 1024 or there's a latency that screws up your
> playing - at 8192 it's a downright 8th note delay...
>

1: update kernel to at least 2.6.11
2: make sure the jack tmpdir is set to a ramdrive (tmpfs)
3: try building jack from cvs (there's been MANY improvements)

As a side note, you can patch gentoo-sources with Ingo's realtime-preempt 
patchset. I've done it and the only failed patches was one to modify the 
kernel tag (pointless and not needed) and a trivial one the fails if you have 
gentoo's custom bootsplash framebuffer (Nothing significant. It just adds 
brackets into an if statement) That patch will speed up the latency quite a 
bit. Use it with caution though because you will trade off speed for 
stability.

You can also muck around with the kernel's compiler flags 
in /usr/src/linux/arch/i386/Makefile but again, you'll be playing with fire.

-Reuben