performance improvements

performance improvements

[Russell Coker]

One thing that could really improve system performance would be something like 
"nice" but for disk IO.

If you have a server that's using 90% of it's disk bandwidth with a large 
number of clients (EG a big mail server) then a simple "find /" is usually 
enough to give it a load average of 50+ and a delay of 1 second for every 
disk request (which makes operations such as POP mail checks excessively 
slow).

-- 
http://www.coker.com.au/selinux/   My NSA Security Enhanced Linux packages
http://www.coker.com.au/bonnie++/  Bonnie++ hard drive benchmark
http://www.coker.com.au/postal/    Postal SMTP/POP benchmark
http://www.coker.com.au/~russell/  My home page

Re: performance improvements

[Ragnar Kjørstad]

On Mon, Dec 23, 2002 at 04:32:26PM +0100, Russell Coker wrote:
> One thing that could really improve system performance would be something like 
> "nice" but for disk IO.

Yes, that would be very nice :)

Preferably it should use scheduling priority directly, so one doesn't
have to set a seperate value / use a seperate utility. 


-- 
Ragnar Kjørstad

Re: performance improvements

[Hendrik Visage]

On Mon, Dec 23, 2002 at 04:59:09PM +0100, Ragnar Kjørstad wrote:
> On Mon, Dec 23, 2002 at 04:32:26PM +0100, Russell Coker wrote:
> > One thing that could really improve system performance would be something like 
> > "nice" but for disk IO.
> 
> Yes, that would be very nice :)
> 
> Preferably it should use scheduling priority directly, so one doesn't
> have to set a seperate value / use a seperate utility. 

BTW: In the later (2.4.19 are so) kernels (I'm not if it was with the
pre-empt patches or not), I've noticed that the nice (especially negative
values) make a significant difference in the I/O bandwidth of the
applications (especially mostly sequencial access)

Perhaps test a "nice find /" and/or a "nice -20 pop3d"

GReetz
Hendrik

Re: performance improvements

[Dieter Nützel]

Am Montag, 23. Dezember 2002 16:32 schrieb Russell Coker:
> One thing that could really improve system performance would be something
> like "nice" but for disk IO.
>
> If you have a server that's using 90% of it's disk bandwidth with a large
> number of clients (EG a big mail server) then a simple "find /" is usually
> enough to give it a load average of 50+ and a delay of 1 second for every
> disk request (which makes operations such as POP mail checks excessively
> slow).

What you are really looking for is the deadline IO scheduler coming with 
2.5/2.6.

Merry Christmas!

-Dieter

-- 
Dieter Nützel
Graduate Student, Computer Science

University of Hamburg
Department of Computer Science
@home: Dieter.Nuetzel at hamburg.de (replace at with @)