On Mon, Feb 03 2014, Puthikorn Voravootivat wrote: > In verify phase, the rand_seed generated on replay does not match > the written rand_seed. > > Multiple problems are causing this: > 1. In verify phase fio does not set io_u->rand_seed to compare with > hdr->rand_seed > 2. In randrw scenario, fio log is stored in red-black tree in "sorted by LBA" > order. Thus, it is imposible to replay the written order, or rather > generate the seeds again in the same order. > 3. In write phase, the code currently will generate rand_seed, write data > and log rand_seed. When queuedepth > 1, it's possible the writes complete > in a different order than rand_seed was generated. Thus when replaying > the log, the generated rand_seed might not match what was written. > 4. verify_backlog option will start verification before all the data has been > written and it make rand_seed replay code broken with current design. > > Proposed fixes: > 1. Use of existing verify_state to generate verify header. > (and assumes this was the original intention of verify_state). And also > adds code to replay rand_seed in verify phase. > 2. If verifysort option is not enabled, store the write log in a list instead > of the red-black tree. Otherwise, don't attempt to verify the rand_seed > in the header. > 3. In write phase, generate rand_seed, log rand_seed, write data. I.e. log > IO transactions in the order generated, not completed. > 4. Don't verify rand_seed when verify_backlog is enabled.
Seems like a reasonable solution to it all. Thanks! I'll get this applied. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe fio" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
