Re: severe regression with random I/O from (at least) 4.14?

2017-12-21 Thread Paolo Valente 


> Il giorno 21 dic 2017, alle ore 11:57, Paolo Valente 
>  ha scritto:
> 
> Hi,
> a few minutes ago I bumped into this apparent severe regression, with 
> 4.15-rc4 and an SSD PLEXTOR PX-256M5S. If, with none as I/O scheduler, I do
> fio --name=global --rw=randread --size=512m --name=job1
> 
> I get
> read : io=524288KB, bw=34402KB/s, iops=8600, runt= 15240msec
> 
> This device had to reach at least 40 KIOPS. I retried with mq-deadline too, 
> and then with a 4.14, same outcome in all cases. I asked some colleague to 
> repeat the test with his/her device. Same outcome, so far, also with an SSD 
> 850 EVO 250GB.
> 
> I'm sorry if I'm making some colossal mistake.
> 

Forget it, sorry. I was confused by a failed test where iodepth was higher than 
1, and I am sleeping too little ...

Thanks,
Paolo

> Thanks,
> Paolo
> 
> 
>

severe regression with random I/O from (at least) 4.14?

2017-12-21 Thread Paolo Valente 
Hi,
a few minutes ago I bumped into this apparent severe regression, with 4.15-rc4 
and an SSD PLEXTOR PX-256M5S. If, with none as I/O scheduler, I do
fio --name=global --rw=randread --size=512m --name=job1

I get
read : io=524288KB, bw=34402KB/s, iops=8600, runt= 15240msec

This device had to reach at least 40 KIOPS. I retried with mq-deadline too, and 
then with a 4.14, same outcome in all cases. I asked some colleague to repeat 
the test with his/her device. Same outcome, so far, also with an SSD 850 EVO 
250GB.

I'm sorry if I'm making some colossal mistake.

Thanks,
Paolo