On Apr 23,  9:00pm, Michael L. Hitch wrote:
> On Apr 23,  9:37pm, "Stephen J. Roznowski" wrote:
> > I'm seeing poor disk performance under NetBSD-current on my A3000.
> > Under ADOS, I see about 1.7-2.0 megabytes per second (via sysinfo)
> > while under NetBSD, I see about 500 kilobytes per second
> > (dd if=/dev/zero of=zzzzz bs=1024k count=10).
...
>   Trying to compare Sysinfo speeds with a filesystem access using
> dd is going to be next to meaningless.  A fairer test would be
> DiskSpeed with 8K buffers.  [Filesystem access is going to use
> the filesystem buffers, which default to 8K.  Also, the data
> being written to the disk has to be copied from the process user
> space to the kernel space buffers, which isn't real efficient either.]

 Also, the equivalent of what Sysinfo does would probably be:
	dd if=/dev/rsd0c of=/dev/null bs=1024k count=10
This will will read directly from the disk to the user buffer without
going through the file system buffers or copying from kernel space to
user space.  The disk read size will be limited to 64K though, because
raw I/O is limited to MAXPHYS.

Michael

-- 
Michael L. Hitch			INTERNET:  osymh@montana.edu
Computer Consultant
Office of Systems and Computing Services
Montana State University	Bozeman, MT	USA