On 9 March 2018 at 07:17, Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: >> Another question about write process with "rw=randwrite" and "bsrange=". If run it with "ioengine=libaio iodepth=16", will this async write get any overlap? > > Maybe (but you can check the "IO depths" output to see what was > actually achieved)? Did you see the warning for libaio in the ioengine > section of the HOWTO > (http://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-ioengine > and look at the libaio heading)? Perhaps I misunderstood what you mean by overlap and just in case I'll check whether you've seen http://fio.readthedocs.io/en/latest/fio_doc.html#cmdoption-arg-norandommap ? When fio picks a random region to write by default it will ensure that each "spot" is only picked once per loop pass and you would have to set norandommap to turn this behaviour off. If you aren't randomly writing multiple loop passes in the same job and you're not writing without a randommap this is normally enough to stop the same region being written by the concurrently submitted I/Os. -- Sitsofe | http://sucs.org/~sits/ -- 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
