Re: [PATCH] block/mq-deadline: Speed up the dispatch of low-priority requests

On 8/26/21 5:49 PM, Bart Van Assche wrote:

On 8/26/21 11:45 AM, Jens Axboe wrote:

quoted

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?

-- 
Jens Axboe