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

From: Nick Piggin
Date: Thu Nov 06 2003 - 08:06:53 EST




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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