On Tue, 31 Mar 2015 19:17:34 +0200 stkoupr <p.kouril@cra.cz> wrote:

> Hi,
> 
> We are testing write performance of md raid5 with SSD array and we are 
> hitting limit which I understand is caused by writes being handled in 
> single thread (md0_raid5 process is eating 100% of 1 CPU core when the 
> test is running). I understood that there is some work in progress which 
> should make write handling multi-threaded. I'd like to ask about the 
> status of this work, is it still in progress or planned?
> 
> Regards,
> Prema
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See /sys/block/mdXXX/md/group_thread_cnt

Set it to a bigger number, get more threads.

Requires 3.12 or later.

NeilBrown