Subject: Re: jerky interactive behavior
To: Perry E. Metzger <perry@piermont.com>
From: haad <haaaad@gmail.com>
List: current-users
Date: 01/21/2007 22:37:21
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Perry E. Metzger wrote:
> "Steven M. Bellovin" <smb@cs.columbia.edu> writes:
>> I recently upgraded my kernel to one from January 8 (and then to one
>> from today).  Before that, I'd been running a mid-December -current.
>>
>> Interactive performance on my Thinkpad T42 has become completely
>> unacceptable.  Something else -- I have no idea what -- occasionally
>> grabs the CPU.  Moving the mouse shows jerky cursor motion, I get
>> doubled input characters, etc.  ps and top show that the machine is
>> mostly idle, though xosview sometimes shows brief spurts of 100% busy.
>> It isn't swapping (it's got 2G of RAM), the interrupt load doesn't seem
>> high (about 1.4-1.6K/sec, with HZ set to 1000), etc.  
>>
>> Is anyone else seeing this?  Anything I should do to tune it?  Might
>> the new scheduler code be part of it?
> 
> I can explain exactly what is going on but not why.
> 
> This sort of thing was very routine for me before before BUFQ_READPRIO
> (which was once called NEW_BUFQ_STRATEGY). Once I added that to my
> kernel years ago, the problem went away. I suspect you have that in
> your kernel.
> 
> As of Jan, something seems to have broken BUFQ_READPRIO -- unclear who
> did it or why, but it is very clear to me that it got broken. The
> old symptoms of lots of disk i/o locking out userland processes trying
> to read something have returned.
> 
> Perry
> 

I don't think so ,because for me I have not lot of disk i/o operations.
When I have these problems.After my school exams I try to look at it.

Any hints, I'm not very skilled in low level OS debuging/monitoring:).

Regards
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Adam Hamsik
ICQ 249727910
jabber haad@jabber.org
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