On 8/26/21 6:03 PM, Bart Van Assche wrote: > On 8/26/21 4:51 PM, Jens Axboe wrote: >> On 8/26/21 5:49 PM, Bart Van Assche wrote: >>> On 8/26/21 11:45 AM, Jens Axboe wrote: >>>> Just ran a quick test here, and I go from 3.55M IOPS to 1.23M switching >>>> to deadline, of which 37% of the overhead is from dd_dispatch(). >>>> >>>> With the posted patch applied, it runs at 2.3M IOPS with mq-deadline, >>>> which is a lot better. This is on my 3970X test box, so 32 cores, 64 >>>> threads. >>> >>> Hi Jens, >>> >>> With the script below, queue depth >= 2 and an improved version of >>> Zhen's patch I see 970 K IOPS with the mq-deadline scheduler in an >>> 8 core VM (i7-4790 CPU). In other words, more IOPS than what Zhen >>> reported with fewer CPU cores. Is that good enough? >> >> That depends, what kind of IOPS are you getting if you revert the >> original change? > > Hi Jens, > > Here is an overview of the tests I ran so far, all on the same test > setup: > * No I/O scheduler: about 5630 K IOPS. > * Kernel v5.11 + mq-deadline: about 1100 K IOPS. > * block-for-next + mq-deadline: about 760 K IOPS. > * block-for-next with improved mq-deadline performance: about 970 K IOPS. So we're still off by about 12%, I don't think that is good enough. That's assuming that v5.11 + mq-deadline is the same as for-next with the mq-deadline change reverted? Because that would be the key number to compare it with. -- Jens Axboe
