[PlanetCCRMA] Re: fedora machine load

[Fernando Lopez-Lezcano]

On Thu, 2005-06-16 at 18:34, Peter Lutek wrote:
> plutek@infinity.net wrote:
> > Fernando Lopez-Lezcano writes:
> >> On Wed, 2005-06-15 at 09:00, Peter Lutek wrote:
> >>
> >>> greetings!
> >>> a while ago, i switched from ccrma/fc2 to gentoo on my laptop, 
> >>> because of  the richer available repository of non-audio packages, 
> >>> and also the  ability to better customize the environment to a given 
> >>> set of hardware. i  am currently considering re-examining ccrma (on 
> >>> fc3), because i want to  spend more time making music, and less time 
> >>> doing sys admin.
> >>> i still have my ccrma/fc2 hard drive, and have recently compared it 
> >>> to my  gentoo install, which is on a separate drive. here are some 
> >>> observations  (both with nothing running except the ion3 window 
> >>> manager and top):
> >>> ccrma/fc2: 62 processes, 218 Mb RAM used
> >>> gentoo: 40 processes, 54 Mb RAM used
> >>> yes, i realize this is a simplistic comparison, but i have to think 
> >>> twice  about moving back to a system which uses almost 1/4 of my 
> >>> available RAM  when it is IDLE (i have 1Gb RAM in this machine).
> >>> so, questions:
> >>> is fc3 better in this respect than fc2?
> >>
> >>
> >> Number of processes running after a stock install? I don't know,
> >> probably not that different. The numbers 62 and 40 don't say much about
> >> what is going on on both machines. A list of _which_ processes are
> >> running on both would be a better start. Most probably a lot of the
> >> processes and services in the fedora machine can be stopped safely, it
> >> all depends on what you need (and this is something you would do once,
> >> of course). 
> >
> well... i've stopped a bunch of services, and the idle memory usage is a 
> little better, but still not what it was with gentoo.
> 
> interestingly, though, i'm getting better audio performance in a simple 
> 18-track ardour recording test than i was in gentoo. jack frames and 
> buffers are at 64 and 2, and i'm getting NO xruns, even when starting 
> and stopping other applications, resizing windows, etc. -- on my gentoo 
> system, i could only barely run at 64/2 and would at least get xruns 
> when starting and stopping ardour. furthermore, with this Planet setup, 
> i'm doing it all as user rather than as root. now that is COOL!

Glad it is working for you (not everyone is so lucky, depends on the
hardware). But do you really have reasons to run at 64x2? For recording
it should not matter, I think. 

BTW, I also think that extra system processes (within reason) should not
really alter your latency results. In the Jack world the audio processes
run with elevated priorities and those are above all other normal
processes, so system processes should just wait. Of course if you are
running a lot of them and a big web server and all that, then memory
usage will impact the system, probably when things start swapping to
disk...

> and the install/tweak/etc. was done in a day. like i said before, more 
> music time is what i want.
> 
> a BIG thankyou to fernando!
> 
> now, there is one remaining curiosity, which perhaps someone can help me 
> sort out: my average load NEVER gets below 1.0, even with no 
> applications running, and it is not solved by a reboot. the machine does 
> not behave like a 1.0-loaded machine, so there's something strange going 
> on here. i've read some references to processes in a D state causing 
> this sort of thing, but there don't appear to be any of those, so i'm at 
> a loss. any clues?

Not really. I've seen this in a laptop here at CCRMA (hi Chris!) and I
did not have any clues as to what was happening. As you say that happens
when processes are stuck waiting for hardware (or something like that),
each one that is stuck increments the load by 1.0. But I did not see
anything so I suspect a kernel bug (or feature?) or something that
changed in the kernel that fools the user space tools into thinking
there is a real load of 1.0. 

-- Fernando