Re: I/O or Threading Suffer

> On Tue, 20 Jul 2004, Scott Long wrote:
>
> > If you are dd'ing from /dev/random, then you are depleting the entropy
> > pool.  Anything else that tries to get random numbers is going to block
> > in strange ways.  Trying just dd'ing from /dev/zero and see if that
> > makes a difference.
>
> With Yarrow, /dev/random should just keep on chugging, so this is unlikely
> to be the source.  However, lots of /dev/random I/O may take a while to
> yield if it's working hard in kernel, so if that is combined with a
> scheduling nit of some sort, we could be looking at a starvation issue.
>
> Do we know if this is on a UP box or SMP box, and if so, whether it's
> using HTT?  I could try reproducing it here and see if I see the same
> thing.
>
> Robert N M Watson             FreeBSD Core Team, TrustedBSD Projects
> robert_at_fledge.watson.org      Principal Research Scientist, McAfee
Research
>
>
>
>
hi,
i have tested it with /dev/zero, /dev/random and /dev/urandom, the same
everywhere.
as i mentioned i noticed the problem while mysqldump was dumping
the mysqldatabase over night. in this timespan the mysqld didnt responsed
to anything. after the dump(3minutes of time) the mysqld was back again and
everything worked again.
i have tested it with 2 UP boxes (i386/pIII) without HTT.