Re: kupdated using all CPU
Tue, 19 Feb 2002 09:42:14 -0800
[Mon, Feb 18, 2002 at 09:53:08PM -0700] firstname.lastname@example.org wrote:
+ Andrew Morton <email@example.com> writes:
+ > john wrote:
+ > >
+ > > [Mon, Feb 18, 2002 at 02:13:06PM -0800] firstname.lastname@example.org wrote:
+ > > + john wrote:
+ > > + >
+ > > + > hi,
+ > > + > ive searched all over and found many references to this problem, but
+ > > + > never found an actual solution. the problem is that during heavy
+ > > + > disk I/O, kupdated will periodically take up ALL the cpu.
+ > > +
+ > > + I've seen a couple of reports of this, nothing to indicate that it's
+ > > + a common problem?
+ > > +
+ > > + In the other reports, it was related to extremely low disk throughput.
+ > > + What does `hdparm -t /dev/hda' say?
+ > >
+ > > root@doom:~# hdparm -t /dev/hda
+ > >
+ > > /dev/hda:
+ > > Timing buffered disk reads: 64 MB in 25.60 seconds = 2.50 MB/sec
+ > ugh. OK, I'll see if I cen reproduce this - there's no reason
+ > why disk suckiness should cause high CPU load. But you need to
+ > pay some attention to your IDE settings in kernel config, and
+ > possibly tuning.
+ Another possibility with the same symptoms is that there are simply
+ very large I/O request starving everything else out. When some
+ crucial data needs to be paged back in. john can you confirm you
+ looked in top and saw kupdate taking 100% of the cpu?
yes, i did. another thing that makes it pretty obvious is the cpu time reported by ps. kupdated cpu time will stay 0:00 until i run into the condition i described. then kupdated cpu time will jump as much as 0:45.
but i have fixed the issue by using the correct ide driver. though, someone may want to look into this anyway...dunno..
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