On 6 March 2018 at 19:02, Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: > Hi, > > On 6 March 2018 at 18:52, abhishek koundal <akoundal@xxxxxxxxx> wrote: >> All >> If the size parameter is not given for the runs, how does the tool >> decide what % (LBA span) needs to be written on the drive? > > It will query the disk/file for its size (but this depends on the > ioengine being able to do that and not all do/can). > >> Reason I am asking as I see different data for the same workloads when >> size=100% and no size parameter used. > > Hmm this sounds like it might be due to a rounding issue - what size > is your disk and what job were you running? https://github.com/axboe/fio/blob/master/filesetup.c#L1039-L1048 shows that when in setup_files() using a size set in percent will round the io_size down to the minimum block size whereas not setting size at all looks like it will pass the determined size straight through unrounded. I'm not sure what job you would see the difference on - perhaps one that did backwards I/O? -- 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
