On Mon, 2008-10-13 at 14:07 -0700, Grant Grundler wrote: > On Mon, Oct 13, 2008 at 12:19 PM, kenneth johansson <ken@xxxxxxxxx> wrote: > > When writing data to /dev/sdb (that is the whole disk and no filesystem) > > it starts out ok around 100MB/sec but soon end up doing considerably > > worse. For prolonged times lasting several minutes it hovers in the > > 20-30MB/sec. > > Is the application using "O_DIRECT"? no just open then write no fancy stuff > If not, could be issue with how VM writeback is (not) working. the access pattern is the simplest possible. Is there any knobs I could try to adjust. > Can you reproduce this using fio or even "dd"? > (See git://git.kernel.dk/fio) dd is having the same effect. -- To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
