Hello!

Whenever I'm watching a dvd, playing a video game or even just watching the screensaver, every so often (around 5 minutes intervals, give or take a minute or two) my computer "skips". Everything slows down for a moment and then has to catch up again. It's somewhat annoying. During these skips, the hard drive is being accessed. And I have no idea what my computer could be doing then. I've shut off all the services I don't use and I don't think it's swapping (although I'm not entirely sure about that one).

Is there a way I can figure out what's happening (and stop it)? I know a little about niceness, but I'm not sure if that'll help (and I'm afraid I'll screw something else up).

Thanks,

Ryan

P.S. I use RedHat 9, and have 256MB of memory on a 400MHZ machine. I usually have about 2GB of free disk space at any given time.

There are issues with IDE I/O in the 2.4.x kernels. However on the way to releasing 2.4.21, some of these issues are reportedly fixed. You can see the changelog here

Try updating to the freshly released 2.4.21 kernel to see if your situation improves.

Hello, again!

Thanks for the quick reply. I updated my kernel and (so far) it looks like it fixed the problem. I read this was a "rare" issue - typical of my luck that I had it.

Anyway, thanks again,

Ryan

Hello!

SHOOT! It's baaaaaack...

Everything was working great after upgrading the kernel, but now, (a couple of days later) the "skipping" problem is happening again. The disk drive access is waaaayyy less obvious than before, but the computer still skips (a little less than before, but still annoying enough). I've timed it... it's exactly every five minutes. The screensaver is off and so is the automatic mail checking (in evolution). I don't know that much about tripwire or anacron... I get a lot of mail from these when I log in as root... could this be the problem?

Thanks in advance (again!),

Ryan

You should check your crons... maybe you'll find that you have something running every 5 minutes.

You didn't mention you're running tripwire or some crontabs in your first post... Arggh! Heheh.

Anyway, the kernel update already does wonders to your HD I/O I assume SO it's not a total waste of time.

Hello!

Well, I guess I can retain the title of "newbie" for a while longer...

I shut off crond and the "skipping" stopped. As I said before, I don't know that much about this stuff, but I'll RTFM to teach myself what it does and what I need it to do before I turn it back on.

The kernel upgrade has made noticeable improvements, btw, so I am glad I did that.

Thanks for the quick replies (and the patience!), your site is great!

Ryan

I've just checked /etc/crontab on my copy of RH9 and didn't see anything there running at precisely 5 minute intervals.

Here's a bit of info picked up someplace else: ext3 journaling daemon flushes journal buffers every 5 minutes... Not sure if it is related to the problem, but might be.

Hey, again!

I've been doing some more testing to narrow down the problem:

1) The skipping problem is directly related to crond. If it's on, skipping; if it's off, no skipping.

2) The skipping happens exactly every 5 minutes (on the zero second, IE, 2:45:00). It's relative to the system time (IE, it's happens at 2:45:00 no matter how long I've been booted up). I've even manually changed the time on my machine to prove it (IE, 5 minutes didn't "actually" pass, i just "tricked" my machine into thinking so).

3) Here's a listing of my crontab:
-----
[root@localhost etc]# cat crontab
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
HOME=/

# run-parts
01 * * * * root run-parts /etc/cron.hourly
02 4 * * * root run-parts /etc/cron.daily
22 4 * * 0 root run-parts /etc/cron.weekly
42 4 1 * * root run-parts /etc/cron.monthly
[root@localhost etc]# ls cron*
crontab

cron.d:
mrtg sysstat

cron.daily:
00-logwatch logrotate slrnpull-expire tripwire-check
00webalizer makewhatis.cron squirrelmail.cron
0anacron rpm tetex.cron
inn-cron-expire slocate.cron tmpwatch

cron.hourly:
diskcheck inn-cron-nntpsend inn-cron-rnews

cron.monthly:
0anacron

cron.weekly:
0anacron makewhatis.cron
-----

As i mentioned before, I don't know a lot about this stuff. I can assume, at this point, it's one of these scripts, but I don't know how to tell which one happens every 5 minutes, and I don't want to just randomly try stuff for fear of messing something else up.

I'm just glad I can watch a DVD (and play chromium!) without the annoying skip! Currently, I just stop/start crond, to control it.

If you guys can give me more incite based on the above, that'd be cool...

Thanks,

Ryan

you can also add a patch to your kernel for desktop
performance. look for Con kolivas on the web.
you can increase the cache size for whatever program
you are using to watch dvd's? mplayer?

~/.mplayer# cat config
# Write your default config options here!
framedrop=yes
cache=16384
double=1
vo = x11
# gui = 1
ao = oss

Hello!

Well, as i figured, starting & stopping crond led to some weird problems (IE alsa would mess up (?)). So, upon further investigation, i found two files in my crontab that were running every five minutes.

The first was mailman. And after I rpm -e this one, the skipping still happened.

The next one was mrtg. And after I rpm -e this one, the skipping stopped.

Finally!

Ryan

P.S. I'm still going to figure out what these are for, but not today - it's beer time!