[ +Cc Hannes ]
On 2016-04-01 15:22, Mike Snitzer wrote:
On Fri, Apr 01 2016 at 4:12am -0400,
Johannes Thumshirn <jthumshirn@xxxxxxx> wrote:
On 2016-03-31 22:04, Mike Snitzer wrote:
>I developed these changes some weeks ago but have since focused on
>regression and performance testing on larger NUMA systems.
>
>For regression testing I've been using mptest:
>https://github.com/snitm/mptest
>
>For performance testing I've been using a null_blk device (with
>various configuration permutations, e.g. pinning memory to a
>particular NUMA node, and varied number of submit_queues).
>
>By eliminating multipath's heavy use of the m->lock spinlock in the
>fast IO paths serious performance improvements are realized.
Hi Mike,
Are this the patches you pointed Hannes to?
If yes, please add my Tested-by: Johannes Thumshirn
<jthumshirn@xxxxxxx>
No they are not.
Hannes seems to have last pulled in my DM mpath changes that (ab)used
RCU.
I ended up dropping those changes and this patchset is the replacement.
Now that you're saying it I can remember some inspiring RCU usage in the
patches.
So please retest with this patchset (I know you guys have a large setup
that these changes are very relevant for). If you could actually share
_how_ yo've tested that'd help me understand how these changes are
holding up. So far all looks good for me...
The test itself is actually quite simple, we're testing with fio against
a fiber channel array (all SSDs but I was very careful to only write
into the cache)
Here's my fio job file:
[mq-test]
iodepth=128
numjobs=40
group_reporting
direct=1
ioengine=libaio
size=3G
filename=/dev/dm-0
filename=/dev/dm-1
filename=/dev/dm-2
filename=/dev/dm-3
filename=/dev/dm-4
filename=/dev/dm-5
filename=/dev/dm-6
filename=/dev/dm-7
name="MQ Test"
and the test runner:
#!/bin/sh
for rw in 'randread' 'randwrite' 'read' 'write'; do
for bs in '4k' '8k' '16k' '32k' '64k'; do
fio mq-test.fio --bs="${bs}" --rw="${rw}"
--output="fio-${bs}-${rw}.txt"
done
done
The initiator has 40 CPUs on 4 NUMA nodes (no HT) and 64GB RAM. I'm not
sure how much in term of numbers I can share from the old patchset (will
ask Hannes on Monday), but I'm aware I'll have to when I retested with
your new patches and we want to compare the results.
Byte,
Johannes
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