Comment 169 for bug 197762

On Wed, Jul 15, 2009 at 01:55:49AM -0000, Theodore Ts'o wrote:
> Eric,
>
> The problem is that your problem may be very different from other
> peoples' problem. First of all, in your test, you are continually
> dirtying the page cache with "cp /dev/zero /mnt/bigfile". This brings
> in filesystem effects, and VM effects, and so it's hard to tell what is
> actually going on.

I was showing the results of the test that Simon propoesed a few posts
earlier. Sorry I didn't attribute my reply properly. It was in response to
the following:

Simon Holm Th\370gersen wrote on 2009-06-09:
> It should literally be something as simple as the following
> (cp bigfile /media/disk/ &) ; sleep 10 ; time echo foo > /media/disk/bar
> If the time is really in seconds as you seem to suggest it is
> interesting I'd say.

Anyway I did also attach iostat output from during the test.

> And certainly the test which you did "(cp /dev/zero /media/disk/bigfile
> &); sleep 10 ; time echo foo > /media/disk/test" is not one that we can
> replicate on Windows, so the assertion that something is wrong is also
> not something which is immediately obvious given the very limited amount
> of information you have given. Maybe it's *somewhere* in this bug
> report, bug this is why it is really not useful to mingle multiple
> users' problems in one bug report.

I'm not sure what to tell you about it not being repeatable on Windows, as
I don't use it. But I think it would be silly to restrict debugging efforts
to only those that can be repeated in Microsoft operating systems,
especially since it may well turn out to be a VM system issue.
I agree that this particular bug report has degenerated into nonsense and
I'll be leaving it alone henceforth.

> [ ... ] you just want to whine
> about how horrible Ubuntu or Linux is, then keep on doing what you're
> doing here. It's not going to lead to anything useful though. But if

Maybe you're mistaking me for someone else. I haven't engaged in any
bashing of Ubuntu or Linux. Fwiw i've commercially deployed thousands of
Ubuntu systems with great success.

oao,
eric