Subject: Re: [linux-audio-user] gentoo mm-sources
From: Gerasimos Grammatikopoulos (dragoon_AT_interfree.it)
Date: Fri Jul 25 2003 - 22:37:20 EEST
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Yet another Gentooer here!
On Friday 25 July 2003 19:14, Paul Winkler wrote:
> On Fri, Jul 25, 2003 at 04:50:41PM +0200, Burkhard Woelfel wrote:
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> > On Friday 25 July 2003 11:37, Chris wrote:
> > > Finally, another gentoo user!
> >
> > Not the only one here... :-)
>
> Indeed. I'm running gentoo on my main box for a few months now.
>
> Regarding kernel patches, with just a little grepping in the portage
> tree I was able to glean the following info...
>
>
> source latency-related info
> ------- ---------------------
> ck-sources "in general his kernels are known to be VERY
> low latency."
> doesn't say what patches are contained, but
> based on notes in other sources, I guess
> LL, PE, and O(1)
My most favorite kernel tree... Unfortunately there have been some issues with
XFS on the .21 releases so I stick to 2.4.20-ck6 atm. Very responsive even at
extreme CPU usage (gcc doing some serious work on a console). Less responsive
than other low-lat versions when your HDD goes postal on I/O. Pretty stable
though.
Keep out of version 2.4.20-ck5... it had some bitter issues
> gaming-sources ebuild contains a URL of a page that tells all:
> http://members.optusnet.com.au/ckolivas/kernel/
> ... at which you can see it contains LL, PE,
> and O(1) among other things.
> Also read the FAQ, it mentions some notable bugs
> e.g. hdparm is broken at least with gaming-sources
> for 2.4.21:
> http://members.optusnet.com.au/ckolivas/kernel/#faq
gaming is another gentoo spin-off based heavily upon ck-sources (ck == Con
Kolivas, also author of the contest kernel benchmark)
> gentoo-sources "Based heavily on ck-sources-2.4.20-r2..."
> contains LL,PE,O(1)
if it's still based on -r2, it's not the most brilliant one. This is one of
the first ck kernels to implement the "elevator" idea for time slices.
> gs-sources contains LL, PE
Never tried it... I believe it's the tree gentoo uses for its liveCDs. Which
means "proven to work on most hardware..." So, if you have issues with other
preemptive, low-lat kernels, I guess this is the one safe choice.
> gentoo-hardened - ck7-base (O(1), preempt, low latency)
Ok, this contains the most relevant bits for low latency but I think is
supposed to concentrate more on security patches.
> mm-sources This is for 2.5/2.6 kernels, which I have not
> really paid attention to. Contains some patches
> from Andrew Morton.
I avoid experimental kernels like the plague... A bug in the FS handling could
be devastating for me... Let's see how 2.6.x turns out, although it's rather
early since there are already some news on failed compiles when using this
kernel.
> wolf-sources "replaced:LowLatency in favor of lowlatency
> fixes from latest -AA"
Actually it's WOLK: Working Overloaded Linux Kernel. The name says it all...
Tried it once, back in the days of 2.4.18. You'll have nightmares in the
night about make menuconfig... There is so much extra stuff in there you
wouldn't believe. Of course, stability is not one of its strengths and it
seams that there is a pattern of time-related "entropy" to the kernel. After
uptimes of > 3 days, things just didn't feel so right. Reboot, and optimal
performance was back. Wouldn't reccomend it for production (making music
after all, IS production) unless you DO need some of the extra patches.
> Note that you still have to pay attention to configuration options:
> e.g. if you don't enable lowlatency and preemptible during kernel
> config, the patches might as well not be there :-)
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