* multi-threaded raid5
@ 2015-03-31 17:17 stkoupr
2015-04-07 1:11 ` NeilBrown
0 siblings, 1 reply; 3+ messages in thread
From: stkoupr @ 2015-03-31 17:17 UTC (permalink / raw)
To: linux-raid
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
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: multi-threaded raid5
2015-03-31 17:17 multi-threaded raid5 stkoupr
@ 2015-04-07 1:11 ` NeilBrown
2015-04-07 4:34 ` Thomas Fjellstrom
0 siblings, 1 reply; 3+ messages in thread
From: NeilBrown @ 2015-04-07 1:11 UTC (permalink / raw)
To: stkoupr; +Cc: linux-raid
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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
> --
> To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
See /sys/block/mdXXX/md/group_thread_cnt
Set it to a bigger number, get more threads.
Requires 3.12 or later.
NeilBrown
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: multi-threaded raid5
2015-04-07 1:11 ` NeilBrown
@ 2015-04-07 4:34 ` Thomas Fjellstrom
0 siblings, 0 replies; 3+ messages in thread
From: Thomas Fjellstrom @ 2015-04-07 4:34 UTC (permalink / raw)
To: NeilBrown, linux-raid
On Tue 07 Apr 2015 11:11:57 AM NeilBrown wrote:
> 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
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-raid" in
> > the body of a message to majordomo@vger.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
> See /sys/block/mdXXX/md/group_thread_cnt
>
> Set it to a bigger number, get more threads.
>
> Requires 3.12 or later.
What does it mean when that property is set to 0?
> NeilBrown
--
Thomas Fjellstrom
thomas@fjellstrom.ca
^ permalink raw reply [flat|nested] 3+ messages in thread
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2015-03-31 17:17 multi-threaded raid5 stkoupr
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2015-04-07 4:34 ` Thomas Fjellstrom
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