Re: horrible disk thorughput on itanium

Marco Colombo
2001-12-07T21:38:09Z

On Fri, 7 Dec 2001, Greg Hennessy wrote:

> In article <Pine.LNX.4.33.0112070941330.8465-100000@penguin.transmeta.com>,
> Linus Torvalds <torvalds@transmeta.com> wrote:
> > bonnie is a _benchmark_. It's meant for finding bad performance. Changing
> > it to make it work better when performance is bad is _pointless_. You've
> > now made the whole point of bonnie go away.
>
> It isn't just bonnie showing bad performance. My application shows it,
> bonnie shows it, and tiobench shows it. I think the focus on putc
> may be too intense. It isn't suprizing to me that either the kernel
> or glibc may not be optimised on ia64, I'm just trying to figure out
> how to get better io rates out of my itanium machine.

Does a simple 'dd' show the problem? I mean,

time dd if=/dev/zero of=/somelargefile count=somelargenumber bs=8k

is it much slower on the itanium, too? dd doesn't use putc(), I hope.

Just for comparison, I've run the following command here:

# time dd if=/dev/zero of=/u2/test count=250000 bs=8k
250000+0 records in
250000+0 records out
0.14user 12.95system 1:23.15elapsed 15%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (117major+18minor)pagefaults 0swaps

(Almost idle box, 256MB RAM, UDMA disk, 2.2.x kernel)

You may try with a bigger file, expecially if you have more RAM.

.TM.
--
____/ ____/ /
/ / / Marco Colombo
___/ ___ / / Technical Manager
/ / / ESI s.r.l.
_____/ _____/ _/ Colombo@ESI.it