> On Mar 21, 2018, at 7:34 AM, Jens Axboe <axboe@xxxxxxxxx> wrote: > > On 3/16/18 12:45 PM, Jeff Furlong wrote: >> A few comments: >> >> -How does the cpu utilization look compared between the lfsr and >> default tausworthe generators? Is the cpu util actually higher on >> lfsr? If it is near saturated on 16 devices, then naturally >> throughput would decrease. > > The LFSR generator is constant overhead, and it should not degrade as > more jobs are using it. There's no shared state at all. Actually it’s only one job. > > If I were to guess, then the identical offsets of the jobs is probably a > likely clue, since that is the only real difference between the two > random generators. Are these 16 volumes all completely separate? > The 16 volumes are coming from the same E8 storage controller. the volumes share the same RAID6 array and the data traffic is flowing through the same Ethernet infrastructure, 100Gb end to en. >From E8 host driver perspective, there is no overhead for more volumes - 1 or 1000 it’s all the same. Michael-- 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
