Hello Minchan,
On (10/07/16 15:33), Minchan Kim wrote:
[..]
> > as soon as wb flush kworker can't keep up anymore things are going off
> > the rails. most of the time, fio-template-static-buffer are in D state,
> > while the biggest bdi flush kworker is doing the job (a lot of job):
> >
> > PID USER PR NI VIRT RES %CPU %MEM TIME+ S COMMAND
> > 6274 root 20 0 0.0m 0.0m 100.0 0.0 1:15.60 R [kworker/u8:1]
> > 11169 root 20 0 718.1m 1.6m 16.6 0.0 0:01.88 D fio
> > ././conf/fio-template-static-buffer
> > 11171 root 20 0 718.1m 1.6m 3.3 0.0 0:01.15 D fio
> > ././conf/fio-template-static-buffer
> > 11170 root 20 0 718.1m 3.3m 2.6 0.1 0:00.98 D fio
> > ././conf/fio-template-static-buffer
> >
> >
> > and still working...
> >
> > 6274 root 20 0 0.0m 0.0m 100.0 0.0 3:05.49 R [kworker/u8:1]
> > 12048 root 20 0 718.1m 1.6m 16.7 0.0 0:01.80 R fio
> > ././conf/fio-template-static-buffer
> > 12047 root 20 0 718.1m 1.6m 3.3 0.0 0:01.12 D fio
> > ././conf/fio-template-static-buffer
> > 12049 root 20 0 718.1m 1.6m 3.3 0.0 0:01.12 D fio
> > ././conf/fio-template-static-buffer
> > 12050 root 20 0 718.1m 1.6m 2.0 0.0 0:00.98 D fio
> > ././conf/fio-template-static-buffer
> >
> > and working...
[..]
> Isn't it blk-mq you mentioned? With blk-mq, I have some concerns.
>
> 1. read speed degradation
> 2. no work with rw_page
> 3. more memory footprint by bio/request queue allocation
yes, I did. and I've seen your concerns in another email - I
just don't have enough knowledge at the moment to say something
not entirely stupid. gotta look more at the whole thing.
> Having said, it's worth to look into it in detail more.
> I will have time to see that approach to know what I can do
> with that.
thanks a lot!
will keep looking as well.
-ss
