Bouts of Extreme System Slug

[Bill Davidsen]

g wrote:
> Oliver Ruebenacker wrote:
> 
>>   The more applications I am running, the more noticeable these phases
>> of sluggishness become,
> 
> more you run, more you load. when you close an app, it does not clear out
> immediately. it has to
> flush buffers and other house cleaning.
> 
> what size swap do you have?
> 
He noted that he wasn't using any of what he has, that's unlikely to be an issue.

>>   How can I diagnose what causes the sluggishness?
> 
> 1st, run 'man top' to see what it is telling you. then run 'top'. when you see
> what is using high
> amount of '%cpu' and '%mem', disable them to see if you are still sluggish.
> 
And iostat and/or vmstat may give you useful information.

> because you are running firefox, clean up history that you do not need. also,
> if you have a lot
> of add-ons, disable what you are not using.
> 
> firefox and thunderbird are both memory hogs. with add-ons, they get worse.
> this is reason to
> disable what you are not always using.
> 
Given that he noted memory use was less than half, and io pressure isn't pushing 
anything to swap, I think that memory pressure is unlikely to be involved. My 
though is an unhappy hard drive, be that wouldn't use all of both CPUs if the 
drive was doing odd retries in firmware.

> also, 'man nice'. changing levels of less important may help.
> 
> what services are running? what services can you disable?
> 
> to run fsck and badblocks, back system up, use a live cd to run checks.
> 
Looking at the remaining space with df and "df -i" is unlikely to be helpful, 
but it's fast and easy, so I usually suggest it. Running vmstat with a 1sec 
delay (into a file) is often useful, when the system is slow it's helpful to 
look at context switches to see if it is hung in a few processes or thrashing 
between many, and knowing if the time spent is in user or system will sometimes 
be a useful clue.

I agree with all the things you said about memory use, but he seems to have no 
indication of that being an issue. Looking at the messages log, running SMART, 
and checking the CPU and disk temp are all things which I think are more likely 
to provide useful information.

I would take a backup ASAP, my guess is that it's a disk error.

-- 
Bill Davidsen <davidsen at tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot