On Fri, Apr 11, 2008 at 08:45:44PM +0200, Jurjen Oskam wrote: > Hi there, > > First, I just received my OpenBSD 4.3 CD set. Thanks for another release! > > Since the harddisk on my laptop was full and I was eager to give 4.3 a > spin, I installed in on a USB stick. The read and write performance of the > stick was much less than I expected, based on how the stick performs under > Linux (on the same machine). > > Under Linux, I get ~30MB/sec read and ~20MB/sec write throughput when doing > "dd if=/dev/stick of=/dev/null bs=16384" and "dd if=/dev/zero of=/dev/stick > bs=16384", respectively. Under OpenBSD, I get ~2,7MB/sec read and 900K/sec > write throughput using dd with the same blocksize. It doesn matter whether > I use GENERIC or GENERIC.MP with or without ACPI enabled, the results are > the same. > > Am I doing something wrong? I've searched the archives, but didn't come up > with anything. >
I presume that /dev/sd0c or sdN[a-k] was used to access the USB device this goes thru the buffer cache which defeats the use of larger blocks under OpenBSD. To accurately compare the I/O speeds use /dev/rsd0c, the raw device. Please be accurate about what is being tested. Dale Rahn [EMAIL PROTECTED]
