[9188] in linux-scsi channel archive
Re: Benchmarking and correctness
daemon@ATHENA.MIT.EDU (Mads Bondo Dydensborg)
Thu Jul 13 14:56:14 2000
Date: Thu, 13 Jul 2000 20:51:00 +0200 (CEST)
From: Mads Bondo Dydensborg <madsdyd@challenge.dk>
To: Brian Pomerantz <bapper@piratehaven.org>
cc: linux-scsi@vger.rutgers.edu
In-Reply-To: <20000713100227.A25305@skull.piratehaven.org>
Message-ID: <Pine.LNX.4.21.0007132048391.27120-100000@challenge.dk>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
On Thu, 13 Jul 2000, Brian Pomerantz wrote:
> On Thu, Jul 13, 2000 at 11:40:20AM +0200, Mads Bondo Dydensborg wrote:
> > Hi there - a couple of questions I hope you will help me with
> >
> > I have made some modifications to a scsi driver, and need to benchmark
> > it. I know about bonnie, but I was wondering if there where other relevant
> > benchmarking utilities?
> >
> > Is there a way to flush the buffer cache? Right now I reboot to make sure
> > I read from the disk, but that is kinda annoying.
> >
> > Also, are there any "correctness" tests? I have a disk connected to the
> > SCSI controller and would like to be sure that I handle all the
> > "neccesary" SCSI commands.
> >
>
> Using a raw device is a good way to get true numbers for your device.
> Even a 'time dd if=/dev/raw1 of=/dev/null' style test can give pretty
> good results
I did that, unfortunatly I got this :
[root@sci10 linux-2.2.13]# time dd if=/dev/sdb of=/dev/null bs=1024k
count=50
50+0 records in
50+0 records out
0.00user 0.93system 0:10.72elapsed 8%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (124major+268minor)pagefaults 0swaps
[root@sci10 linux-2.2.13]# time dd if=/dev/sdb of=/dev/null bs=1024k
count=50
50+0 records in
50+0 records out
0.01user 0.62system 0:04.20elapsed 15%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (83major+268minor)pagefaults 0swaps
The 2. run is more then twice as fast. Obviously there must be some
buffering still taking place?
Mads
P.S. Yes, this is old/slow hardware.
--
Mads Bondo Dydensborg. madsdyd@challenge.dk
UNIX always presumes you know what you're doing. You're the human being,
after all, and it is a mere operating system.
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