On Thu, Jul 16 2009, Richard Kennedy wrote: > Running tests of fio write with sizes that are less than the write cache > size I'm seeing a big slow down when using mmap. I'm running the tests > on linux 2.6.31-rc* x86_64. > > Typical results with default writes :- > > fio size=300m rw=write > write: io=300MiB, bw=314MiB/s, iops=80,418, runt= 955msec > > with mmap :- > > fio size=300m rw=write ioengine=mmap > write: io=300MiB, bw=55,732KiB/s, iops=13,933, runt= 5512msec > > > Is this expected or is it indicative of a problem somewhere? What does the full job file look like? Is the file cached, or are the faults reading in data? -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
