Thanks for the mentioning the 'loops' option. But still, it is weird that by changing ioengine, iolog will report differently. I think either sync mistakenly performs only one loop, or the IO is done correctly but iolog report is wrong. I think the expected behavior is that iolog is the same for both sync and libaio. And both of them should follow the HOW: "if 'size' is set to 21G, and 'io_size' is set to 40G, then fio will do 40G of IO within the 0..20G region." Jun On Thu, Dec 10, 2015 at 12:56 AM, Sitsofe Wheeler <sitsofe@xxxxxxxxx> wrote: > Hi, > > Your job sets and io_size four times that of "size" of the disk that > you are using. This will force your I/O to wrap abound to the start of > the region (why not use loops?). Are you saying that you think the > sync job's iolog is wrong because it only says it performed one loop? > > On 9 December 2015 at 02:50, Jun He <jhe@xxxxxxxxxxx> wrote: >> Hi all, >> I think there is a bug for io_size. >> >> For example, I want to write 16KB data to a file of size 8KB (so each block is >> written twice) and I have the following job file: >> >> [global] >> ioengine=sync >> rw=write >> bs=4kb >> size=8kb >> io_size=32kb >> >> [job1] >> write_iolog=iolog.1 >> >> >> After running, iolog.1 will contain the following contents: >> >> fio version 2 iolog >> job1.0.0 add >> job1.0.0 open >> job1.0.0 write 0 4096 >> job1.0.0 write 4096 4096 >> job1.0.0 close >> >> This shows that each block has been only written once. >> >> If I change the ioengine to libaio, iolog.1 will contain: >> >> fio version 2 iolog >> job1.0.0 add >> job1.0.0 open >> job1.0.0 write 0 4096 >> job1.0.0 write 4096 4096 >> job1.0.0 close >> job1.0.0 open >> job1.0.0 write 0 4096 >> job1.0.0 write 4096 4096 >> job1.0.0 close >> job1.0.0 open >> job1.0.0 write 0 4096 >> job1.0.0 write 4096 4096 >> job1.0.0 close >> job1.0.0 open >> job1.0.0 write 0 4096 >> job1.0.0 write 4096 4096 >> job1.0.0 close >> >> >> Bug or wrong usage? >> >> Thanks, >> Jun >> >> >> >> -- >> 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 > > > > -- > 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
