On Fri, Apr 11, 2008 at 08:45:44PM +0200, Jurjen Oskam wrote: > 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 wonder if there's a buffering thing going on. Under both os's, what happens if you time it from the start of dd to the time the light stops flashing and you could remove the stick. Perhaps linux's dd is returning while the data is still being written. Just a thought. Doug.
