On 08/11/2014 10:56 PM, Sitsofe Wheeler wrote: > (Resending with list cc) > > On 7 August 2014 22:27, Jens Axboe <axboe@xxxxxxxxx> wrote: >> On 08/05/2014 09:22 AM, Sitsofe Wheeler wrote: >>> When trying to use fio from git >>> ae7e055f755e77dfa71ae9040250ce8eec238721 (commit dated July 25th) the >>> following line always fails at the same point: >>> >>> ./fio --randseed=1 --ioengine=libaio --iodepth=1 --bs=64k >>> --rw=randwrite --verify=meta --verify_backlog=50 --filename >>> /dev/shm/foo --size=8M --time_based --runtime=1m --name=go >>> >>> Switching --loops=4 for --time_based --runtime=1m doesn't resulted in >>> the same error. >>> >>> Is this fio job malformed? >> >> No, the job is fine, it's yet another case where the numberio >> verification for meta fails miserably. Try current git, I committed a >> one liner for it. > > Yup that fixes it. I've got one more mismatch query although with a > different job file: > > fio --thread --direct=1 --ioengine=libaio --iodepth=128 --bs=64k > --rw=randwrite --verify=xxhash --verify_backlog=50 --filename > /dev/sdaw --name=go --time_based --runtime=2m --size=1M > > I've got a case where this generates verification error before the job > completes. However on most of the other disks I have tried (virtual > disks, RAM disks etc) this job runs without issues. Once again > replacing --time_based --runtime with --loops makes the issue go > aways. Further, switching the ioscheduler for this disk from cfq to > noop also makes the problem go away (I've disabled merging by echoing > 1 into nomerges)... > > Could it be this job submits different I/O to the same position in the > same batch? If so isn't the result undefined? Why would using noop > solve the issue? It's most likely a bug that is timing dependent, which is why certain changes to the IO path below fio will make a difference. I'll take a look at this. -- 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
