Re: 2.9test9-mm1 and DAO ATAPI cd-burning corrupt

[Nick Piggin]

Jens Axboe wrote:

> On Thu, Nov 06 2003, Nick Piggin wrote:
>
> > Prakash K. Cheemplavam wrote:
> >
> >
> > > > > procs -----------memory---------- ---swap-- -----io---- --system-- 
> > > > > ----cpu----
> > > > > r  b   swpd   free   buff  cache   si   so    bi    bo   in    cs us 
> > > > > sy id wa
> > > > > 2  0      0 579472  13976 308572    0    0   425    85 1255   645  5 
> > > > > 3 84  9
> > > > > 2  0      0 579456  13976 308572    0    0     0     0  725   521  5 
> > > > > 5 91  0
> > > > > 1  0      0 579448  13976 308572    0    0     0     0  736   523  2 
> > > > > 5 94  0
> > > > > 0  0      0 579448  13976 308572    0    0     0    25  745   439  2 
> > > >
> > > >
> > > > [snip]
> > > >
> > > > This looks good, from a system utilization point of view. I'm wondering
> > > > whether you have the iso image cached? There's no block io going on.
> > > >
> > > > It does like more like a CPU scheduler problem at this point.
> > >
> > >
> > > Ok, then it is Nick's turn, I guess. :-) Yeah most probably the iso is 
> > > cached, as it was not the first time I burnt the iso when I did the 
> > > vmstat, furthermore I have 1 GB of RAM... The other thing which 
> > > doesn't speack for i/o problems, I guess: Just the first seconds when 
> > > I start erasing the CD-RW the mouse hangs and heavily stutters, then 
> > > it is OK until actual burning of image begins, then the mouse slightly 
> > > stutters. All this was not with test9-mm1.
> > I don't think the scheduler is the problem if you didn't have these problems
> > in mm1. The scheduler is quite good when nothing is reniced. Whats funny
> > though is it looks like you're losing timer interrupts, this is a sign that
> > something is holding interrupts off for too long, and would also cause
> > problems with your mouse.
>
> sys time is usually pretty high if that is the case, and it's hovering
> around 5% here... Prakash, are you sure that dma is enabled on the
> drive? When you see the problem, do a vmstat 1 for 10 seconds so you are
> absolutely sure you are sending the info from when the problem occurs.

Although have a look at the interrupts field in vmstat 1255, 725, 736 ...

> > I guess its over to Andrew.
>
> Back to you, Kent! :-)

:)

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