2.6.23 kernel patched w/ patch-2.6.23-rt1 = massive problems

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leadghost
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Just a heads up: I build the latest and greatest kernel w/ rt patches and suffered a horrible performance loss. Desktop performance was awful and had xruns like crazy. I'd advise sticking with an older build for now.

thorgal
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I am experiencing the opposite situation, performance is better for me. I went through a quite drastic OS upgrade because my kubuntu 'dist-upgrade' introduced really weird bugs, among which a complete ignorance of my HDSP PCI card at every boot + X screwed (fonts not visible, text totally gone from X objects, never seen this before). I installed 64Studio that I upgraded to Debian Sid (so back to my preferred linux distro). I set up the usual stuff (rtlimits, etc) and I could get even more down in frames (64 frames at 96kHz) without any xruns. At the end, it was worth the effort ...

FYI, here is my software conf :


/etc/security/limits.conf
@audio - rtprio 99
@audio - memlock 1000000 (I've got 4G of mem)
@audio - nice -10

JACK conf :
/usr/bin/jackd -R -P70 -u -dalsa -dhw:0 -r96000 -p64 -n2 -H

IRQ related stuff : haven't touched it myself.

My h/w is RME HDSP Multiface II, mobo DG965SS, CPU Core 2 Duo E6600 (2x2.4 GHz), RAM 4G, SATAII HDs. All of this packed in an Antech Sonata III case, cooled down by some neat Zalman coolers.

thorgal
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well, actually I am experiencing something a bit odd, which did not happen before : the connection to my LAN is unstable. As soon as jackd is off, it's OK. I did not mention that I am in fact using jackdmp. I will try the old jackd and see how the connectivity to my LAN goes.

thorgal
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OK, not using jackdmp but jackd seems to make the connection to the LAN stable. But on the other hand, I get a couple of xruns as I open or close some programs. I am not sure about what jackdmp does that removes all xruns but the LAN thing is certainly an issue to me ...

thorgal
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LAN issue gone with jackdmp 0.67 compiled from source. No clue as to why it happened in the first place ...

EDIT: I did eventually get a LAN problem. But I don't think it is jack related since JACK was not on when it happened last ...

porl
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i'm using a 2.6.23-rt kernel on ubuntustudio and it is the first time i have been able to get reliable sub 6ms performance. i can even get down under 3ms but i have had it drop out on me once when i was pushing it to see how far i could go (actually, it was running 'oblivion' under wine in compiz whilst spinning the cube that dropped ardour out, so i'm not sure i can blame it :) note though that i had to compile it a few times with various options before i found one that worked. my early attempts had xruns galore (but so does the ubuntustudio -rt kernel for me for some reason).

i have had no end of trouble with other kernels, the only pre 2.6.23 kernel i was successful with was 64studio's 2.6.22 kernel (installed it on ubuntu manually), but that had no firewire support for some reason and i'm trying to get my new saffire pro working.

anyway, the good thing with linux is you can try the new kernel parallel to your current one and try it to see for yourself.

thorgal
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hey Porl, nice to hear :)

One thing though : aren't you mixing up ubuntu and debian packages ? not that they drastically differ but the package dependencies are certainly quite different. How did it go with forcing a debian kernel into an ubuntu system ?

regarding my LAN issue, looked like related to some hwmon stuff (nothing to do with JACK). It's quite stable now and that's fine with me :)

porl
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the kernel packages are pretty self contained, just depending on their respective modules packages really. i didn't add the repository to apt though, i used dpkg on the deb files. they installed cleanly with no problems.

porl

ps. actually i think i needed to change the nvidia-glx package to the 64studio one as well, can't remember.

thorgal
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spoke too fast, connection to LAN still erratic but not as much since I compiled my own version of the network driver (e1000, version 7.6.9) ... without any log or messages from the system, it is hard to determine but this is OT.

thorgal
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OK, after using 2.6.23 for a while (even with the latest RT patch), I get random problems. I though it was better at first but honestly, things are going weird at times (LAN problems, xruns popping up for no apparent reasons, etc). I am going back to 2.6.22 ...

Update: way better in terms of stability! no more LAN issues, etc, rock solid ...

kelargo
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is 2.6.23 still having issues?
I thought I'd give 2.6.23-gentoo-r1 try

porl
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as i said above, it works great for me. seems to me that its worth giving it a go. you can always roll back if it doesn't work for you.

porl

kelargo
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I seem to get many more xruns than with the previous release
kernel-2.6.22-gentoo-r5.

How much memory do you have? I am going to install some more RAM just to see if that has any impact.

porl
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i've only got 1gig of ram. while i definitely want to increase it, it doesn't seem to cause any problems for me with xruns.

porl

porl
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just in case it helps, i have posted my (new since last post as i reformatted back to 32 bit) kernel config file here. it was used on the git version of the kernel here: git://git.kernel.org/pub/scm/linux/kernel/git/cloos/rt-2.6.git

it is 2.6.23.1-rt5. i haven't had any problems with it yet, but i did have issues with a different configuration (which i can't figure out) on the same kernel. maybe it will help someone else as a starting point.

porl

ps. it is configured with initramdisk support, so if you don't want that i assume you would have to change some modules to be hardcoded into the kernel.

breakerfall
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I switched to 2.6.26.3 when it was released and didn't notice any loss of performance, however, it seems to break MIDI in an unpredictable way. This was confirmed in the linux audio developers irc channel, where I was told that 2.6.26.3 broke MIDI and had performance issues... back to 2.6.25.8 I went hehe.

mrorange (not verified)

great post sir..
thanks for sharing. really helped a lot here.
regards,

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