"why is my Linux so damn slow?"

[Rick Sewill]

On Saturday, February 12, 2011 12:27:55 pm Rick Sewill wrote:
> On Saturday, February 12, 2011 12:09:34 pm M. Fioretti wrote:
> > On Sat, Feb 12, 2011 19:03:56 PM +0100, Marco Fioretti
> 
> (mfioretti at nexaima.net) wrote:
> > > On Sat, Feb 12, 2011 12:55:16 PM -0500, Lamar Owen (lowen at pari.edu) 
wrote:
> > > > On Saturday, February 12, 2011 12:19:33 pm M. Fioretti wrote:
> > > > > besides hard drive and DVD burner there are only Logitech webcam,
> > > > > wheelmouse and earphone microphone, but everything is plugged in
> > > > > the back which is not really accessible without moving
> > > > > furniture. I'll do that if needed, but isn't a way to check for
> > > > > those interrupts from the prompt?
> > > > 
> > > > Let's see if iowaits are you issue.  Install the sysstat package
> > > > (yum install sysstat) and run: iostat -x 1
> > > 
> > > here it is, thanks for the tip. When it isn't zero, the await column
> > > gives anything from 27.36 to 35.78 (last line) to 5 (I have already
> > > posted top output in a comment to the web page):
> > > 
> > > [root at polaris ~]# iostat -x 1 | egrep -i 'device|sda'
> > 
> > Sorry, of course that's only the part of the story about sda. here is one
> > complete run of iostat:
> > 
> > 
> > Device:         rrqm/s   wrqm/s     r/s     w/s   rsec/s   wsec/s
> > avgrq-sz avgqu-sz   await  svctm  %util sda               0.00     5.00 
> >   0.00 5.00     0.00    64.00    12.80     0.03    6.00   6.00   3.00
> > dm-0
> > 
> >       0.00     0.00    0.00    8.00     0.00    64.00     8.00     0.04
> > 
> > 4.38   3.75   3.00 dm-1              0.00     0.00    0.00    0.00
> > 0.00     0.00     0.00     0.00    0.00   0.00   0.00
> > 
> > other runs show all null values for  dm-0 / dm-1, or values similar to
> > these
> > 
> > Marco
> 
> Could you show the output of iostat -x 1,
> not iostat -x 1 | egrep -i 'device|sda'
> please?
> 
> On my system, when I do
> iostat -x 1
> I get "avg-cpu" besides drive information.
> avg-cpu:  %user   %nice %system %iowait  %steal   %idle
>            5.05    0.00    4.04    0.00    0.00   90.91
> 
> Device:         rrqm/s   wrqm/s     r/s     w/s   rsec/s   wsec/s avgrq-sz
> avgqu-sz   await  svctm  %util
> sda               0.00     0.00    0.00    0.00     0.00     0.00     0.00
> 0.00    0.00   0.00   0.00
> 
> It might help to see the "avg-cpu".
> If we are lucky, either the %user or %system or ... will show high cpu
> usage.

Another question please...if it's spurious interrupts, I found the device file,
/proc/interrupts, which has a row for Spurious interrupts.

We haven't demonstrated the problem is interrupt related.
Can we try to isolate or rule out this as a problem please?

Could you show us the output of twice, the second time a few seconds
after the first time so we can see if any interrupt number changes fast. 
more /proc/interrupts
...
more /proc/interrupts

Can people suggest any information/files in /proc which might help us?

I assume there is a periodic hardware clock interrupt for your CPU.
Can we find out this clock interrupt rate somewhere?
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 198 bytes
Desc: This is a digitally signed message part.
Url : http://lists.fedoraproject.org/pipermail/users/attachments/20110212/45fd851f/attachment.bin