> -----Original Message----- > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of > Somnath Roy > Sent: 11 September 2015 06:23 > To: Rafael Lopez <rafael.lopez@xxxxxxxxxx> > Cc: ceph-users@xxxxxxxxxxxxxx > Subject: Re: bad perf for librbd vs krbd using FIO > > That’s probably because the krbd version you are using doesn’t have the > TCP_NODELAY patch. We have submitted it (and you can build it from latest > rbd source) , but, I am not sure when it will be in linux mainline. >From memory it landed in 3.19, but there are also several issues with max IO size, max nr_requests and readahead. I would suggest for testing, try one of these:- http://gitbuilder.ceph.com/kernel-deb-precise-x86_64-basic/ref/ra-bring-back/ > > Thanks & Regards > Somnath > > From: Rafael Lopez [mailto:rafael.lopez@xxxxxxxxxx] > Sent: Thursday, September 10, 2015 10:12 PM > To: Somnath Roy > Cc: ceph-users@xxxxxxxxxxxxxx > Subject: Re: bad perf for librbd vs krbd using FIO > > Ok I ran the two tests again with direct=1, smaller block size (4k) and smaller > total io (100m), disabled cache at ceph.conf side on client by adding: > > [client] > rbd cache = false > rbd cache max dirty = 0 > rbd cache size = 0 > rbd cache target dirty = 0 > > > The result seems to have swapped around, now the librbd job is running > ~50% faster than the krbd job! > > ####### krbd job: > > [root@rcprsdc1r72-01-ac rafaell]# fio ext4_test > job1: (g=0): rw=rw, bs=4K-4K/4K-4K/4K-4K, ioengine=sync, iodepth=16 > fio-2.2.8 > Starting 1 process > Jobs: 1 (f=1): [W(1)] [100.0% done] [0KB/571KB/0KB /s] [0/142/0 iops] [eta > 00m:00s] > job1: (groupid=0, jobs=1): err= 0: pid=29095: Fri Sep 11 14:48:21 2015 > write: io=102400KB, bw=647137B/s, iops=157, runt=162033msec > clat (msec): min=2, max=25, avg= 6.32, stdev= 1.21 > lat (msec): min=2, max=25, avg= 6.32, stdev= 1.21 > clat percentiles (usec): > | 1.00th=[ 2896], 5.00th=[ 4320], 10.00th=[ 4768], 20.00th=[ 5536], > | 30.00th=[ 5920], 40.00th=[ 6176], 50.00th=[ 6432], 60.00th=[ 6624], > | 70.00th=[ 6816], 80.00th=[ 7136], 90.00th=[ 7584], 95.00th=[ 7968], > | 99.00th=[ 9024], 99.50th=[ 9664], 99.90th=[15808], 99.95th=[17536], > | 99.99th=[19328] > bw (KB /s): min= 506, max= 1171, per=100.00%, avg=632.22, stdev=104.77 > lat (msec) : 4=2.88%, 10=96.69%, 20=0.43%, 50=0.01% > cpu : usr=0.17%, sys=0.71%, ctx=25634, majf=0, minf=35 > IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, > >=64=0.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > issued : total=r=0/w=25600/d=0, short=r=0/w=0/d=0, > drop=r=0/w=0/d=0 > latency : target=0, window=0, percentile=100.00%, depth=16 > > Run status group 0 (all jobs): > WRITE: io=102400KB, aggrb=631KB/s, minb=631KB/s, maxb=631KB/s, > mint=162033msec, maxt=162033msec > > Disk stats (read/write): > rbd0: ios=0/25638, merge=0/32, ticks=0/160765, in_queue=160745, > util=99.11% > [root@rcprsdc1r72-01-ac rafaell]# > > ###### librb job: > > [root@rcprsdc1r72-01-ac rafaell]# fio fio_rbd_test > job1: (g=0): rw=rw, bs=4K-4K/4K-4K/4K-4K, ioengine=rbd, iodepth=16 > fio-2.2.8 > Starting 1 process > rbd engine: RBD version: 0.1.9 > Jobs: 1 (f=1): [W(1)] [100.0% done] [0KB/703KB/0KB /s] [0/175/0 iops] [eta > 00m:00s] > job1: (groupid=0, jobs=1): err= 0: pid=30568: Fri Sep 11 14:50:24 2015 > write: io=102400KB, bw=950141B/s, iops=231, runt=110360msec > slat (usec): min=70, max=992, avg=115.05, stdev=30.07 > clat (msec): min=13, max=117, avg=67.91, stdev=24.93 > lat (msec): min=13, max=117, avg=68.03, stdev=24.93 > clat percentiles (msec): > | 1.00th=[ 19], 5.00th=[ 26], 10.00th=[ 38], 20.00th=[ 40], > | 30.00th=[ 46], 40.00th=[ 62], 50.00th=[ 77], 60.00th=[ 85], > | 70.00th=[ 88], 80.00th=[ 91], 90.00th=[ 95], 95.00th=[ 99], > | 99.00th=[ 105], 99.50th=[ 110], 99.90th=[ 116], 99.95th=[ 117], > | 99.99th=[ 118] > bw (KB /s): min= 565, max= 3174, per=100.00%, avg=935.74, stdev=407.67 > lat (msec) : 20=2.41%, 50=29.85%, 100=64.46%, 250=3.29% > cpu : usr=2.43%, sys=0.29%, ctx=7847, majf=0, minf=2750 > IO depths : 1=6.2%, 2=12.5%, 4=25.0%, 8=50.0%, 16=6.2%, 32=0.0%, > >=64=0.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > complete : 0=0.0%, 4=94.1%, 8=0.0%, 16=5.9%, 32=0.0%, 64=0.0%, > >=64=0.0% > issued : total=r=0/w=25600/d=0, short=r=0/w=0/d=0, > drop=r=0/w=0/d=0 > latency : target=0, window=0, percentile=100.00%, depth=16 > > Run status group 0 (all jobs): > WRITE: io=102400KB, aggrb=927KB/s, minb=927KB/s, maxb=927KB/s, > mint=110360msec, maxt=110360msec > > Disk stats (read/write): > dm-1: ios=240/369, merge=0/0, ticks=742/40, in_queue=782, util=0.38%, > aggrios=240/379, aggrmerge=0/19, aggrticks=742/41, aggrin_queue=783, > aggrutil=0.39% > sda: ios=240/379, merge=0/19, ticks=742/41, in_queue=783, util=0.39% > [root@rcprsdc1r72-01-ac rafaell]# > > > > Confirmed speed (at least for krbd) using dd: > [root@rcprsdc1r72-01-ac rafaell]# dd if=/mnt/ssd/random100g > of=/mnt/rbd/dd_io_test bs=4k count=10000 oflag=direct > 10000+0 records in > 10000+0 records out > 40960000 bytes (41 MB) copied, 64.9799 s, 630 kB/s > [root@rcprsdc1r72-01-ac rafaell]# > > > Back to FIO, it's worse for 1M block size (librbd is about ~100% better perf). > 1M librbd: > Run status group 0 (all jobs): > WRITE: io=1024.0MB, aggrb=112641KB/s, minb=112641KB/s, > maxb=112641KB/s, mint=9309msec, maxt=9309msec > > 1M krbd: > Run status group 0 (all jobs): > WRITE: io=1024.0MB, aggrb=49939KB/s, minb=49939KB/s, maxb=49939KB/s, > mint=20997msec, maxt=20997msec > > Raf > > On 11 September 2015 at 14:33, Somnath Roy <Somnath.Roy@xxxxxxxxxxx> > wrote: > Only changing client side ceph.conf and rerunning the tests is sufficient. > > Thanks & Regards > Somnath > > From: Rafael Lopez [mailto:rafael.lopez@xxxxxxxxxx] > Sent: Thursday, September 10, 2015 8:58 PM > To: Somnath Roy > Cc: ceph-users@xxxxxxxxxxxxxx > Subject: Re: bad perf for librbd vs krbd using FIO > > Thanks for the quick reply Somnath, will give this a try. > > In order to set the rbd cache settings, is it a matter of updating the ceph.conf > file on the client only prior to running the test, or do I need to inject args to all > OSDs ? > > Raf > > > On 11 September 2015 at 13:39, Somnath Roy <Somnath.Roy@xxxxxxxxxxx> > wrote: > It may be due to rbd cache effect.. > Try the following.. > > Run your test with direct = 1 both the cases and rbd_cache = false (disable all > other rbd cache option as well). This should give you similar result like krbd. > > In direct =1 case, we saw ~10-20% degradation if we make rbd_cache = true. > But, direct = 0 case, it could be more as you are seeing.. > > I think there is a delta (or need to tune properly) if you want to use rbd > cache. > > Thanks & Regards > Somnath > > > > From: ceph-users [mailto:ceph-users-bounces@xxxxxxxxxxxxxx] On Behalf Of > Rafael Lopez > Sent: Thursday, September 10, 2015 8:24 PM > To: ceph-users@xxxxxxxxxxxxxx > Subject: bad perf for librbd vs krbd using FIO > > Hi all, > > I am seeing a big discrepancy between librbd and kRBD/ext4 performance > using FIO with single RBD image. RBD images are coming from same RBD > pool, same size and settings for both. The librbd results are quite bad by > comparison, and in addition if I scale up the kRBD FIO job with more > jobs/threads it increases up to 3-4x results below, but librbd doesn't seem to > scale much at all. I figured that it should be close to the kRBD result for a > single job/thread before parallelism comes into play though. RBD cache > settings are all default. > > I can see some obvious differences in FIO output, but not being well versed > with FIO I'm not sure what to make of it or where to start diagnosing the > discrepancy. Hunted around but haven't found anything useful, any > suggestions/insights would be appreciated. > > RBD cache settings: > [root@rcmktdc1r72-09-ac rafaell]# ceph --admin-daemon > /var/run/ceph/ceph-osd.659.asok config show | grep rbd_cache > "rbd_cache": "true", > "rbd_cache_writethrough_until_flush": "true", > "rbd_cache_size": "33554432", > "rbd_cache_max_dirty": "25165824", > "rbd_cache_target_dirty": "16777216", > "rbd_cache_max_dirty_age": "1", > "rbd_cache_max_dirty_object": "0", > "rbd_cache_block_writes_upfront": "false", > [root@rcmktdc1r72-09-ac rafaell]# > > This is the FIO job file for the kRBD job: > > [root@rcprsdc1r72-01-ac rafaell]# cat ext4_test > ; -- start job file -- > [global] > rw=rw > size=100g > filename=/mnt/rbd/fio_test_file_ext4 > rwmixread=0 > rwmixwrite=100 > percentage_random=0 > bs=1024k > direct=0 > iodepth=16 > thread=1 > numjobs=1 > [job1] > ; -- end job file -- > > [root@rcprsdc1r72-01-ac rafaell]# > > This is the FIO job file for the librbd job: > > [root@rcprsdc1r72-01-ac rafaell]# cat fio_rbd_test > ; -- start job file -- > [global] > rw=rw > size=100g > rwmixread=0 > rwmixwrite=100 > percentage_random=0 > bs=1024k > direct=0 > iodepth=16 > thread=1 > numjobs=1 > ioengine=rbd > rbdname=nas1-rds-stg31 > pool=rbd > [job1] > ; -- end job file -- > > > Here are the results: > > [root@rcprsdc1r72-01-ac rafaell]# fio ext4_test > job1: (g=0): rw=rw, bs=1M-1M/1M-1M/1M-1M, ioengine=sync, iodepth=16 > fio-2.2.8 > Starting 1 thread > job1: Laying out IO file(s) (1 file(s) / 102400MB) > Jobs: 1 (f=1): [W(1)] [100.0% done] [0KB/321.7MB/0KB /s] [0/321/0 iops] [eta > 00m:00s] > job1: (groupid=0, jobs=1): err= 0: pid=37981: Fri Sep 11 12:33:13 2015 > write: io=102400MB, bw=399741KB/s, iops=390, runt=262314msec > clat (usec): min=411, max=574082, avg=2492.91, stdev=7316.96 > lat (usec): min=418, max=574113, avg=2520.12, stdev=7318.53 > clat percentiles (usec): > | 1.00th=[ 446], 5.00th=[ 458], 10.00th=[ 474], 20.00th=[ 510], > | 30.00th=[ 1064], 40.00th=[ 1096], 50.00th=[ 1160], 60.00th=[ 1320], > | 70.00th=[ 1592], 80.00th=[ 2448], 90.00th=[ 7712], 95.00th=[ 7904], > | 99.00th=[11072], 99.50th=[11712], 99.90th=[13120], 99.95th=[73216], > | 99.99th=[464896] > bw (KB /s): min= 264, max=2156544, per=100.00%, avg=412986.27, > stdev=375092.66 > lat (usec) : 500=18.68%, 750=7.43%, 1000=2.11% > lat (msec) : 2=48.89%, 4=4.35%, 10=16.79%, 20=1.67%, 50=0.03% > lat (msec) : 100=0.03%, 250=0.02%, 500=0.01%, 750=0.01% > cpu : usr=1.24%, sys=45.38%, ctx=19298, majf=0, minf=974 > IO depths : 1=100.0%, 2=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, > >=64=0.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > issued : total=r=0/w=102400/d=0, short=r=0/w=0/d=0, > drop=r=0/w=0/d=0 > latency : target=0, window=0, percentile=100.00%, depth=16 > > Run status group 0 (all jobs): > WRITE: io=102400MB, aggrb=399740KB/s, minb=399740KB/s, > maxb=399740KB/s, mint=262314msec, maxt=262314msec > > Disk stats (read/write): > rbd0: ios=0/150890, merge=0/49, ticks=0/36117700, in_queue=36145277, > util=96.97% > [root@rcprsdc1r72-01-ac rafaell]# > > [root@rcprsdc1r72-01-ac rafaell]# fio fio_rbd_test > job1: (g=0): rw=rw, bs=1M-1M/1M-1M/1M-1M, ioengine=rbd, iodepth=16 > fio-2.2.8 > Starting 1 thread > rbd engine: RBD version: 0.1.9 > Jobs: 1 (f=1): [W(1)] [100.0% done] [0KB/65405KB/0KB /s] [0/63/0 iops] [eta > 00m:00s] > job1: (groupid=0, jobs=1): err= 0: pid=43960: Fri Sep 11 12:54:25 2015 > write: io=102400MB, bw=121882KB/s, iops=119, runt=860318msec > slat (usec): min=355, max=7300, avg=908.97, stdev=361.02 > clat (msec): min=11, max=1468, avg=129.59, stdev=130.68 > lat (msec): min=12, max=1468, avg=130.50, stdev=130.69 > clat percentiles (msec): > | 1.00th=[ 21], 5.00th=[ 26], 10.00th=[ 29], 20.00th=[ 34], > | 30.00th=[ 37], 40.00th=[ 40], 50.00th=[ 44], 60.00th=[ 63], > | 70.00th=[ 233], 80.00th=[ 241], 90.00th=[ 269], 95.00th=[ 367], > | 99.00th=[ 553], 99.50th=[ 652], 99.90th=[ 832], 99.95th=[ 848], > | 99.99th=[ 1369] > bw (KB /s): min=20363, max=248543, per=100.00%, avg=124381.19, > stdev=42313.29 > lat (msec) : 20=0.95%, 50=55.27%, 100=5.55%, 250=24.83%, 500=12.28% > lat (msec) : 750=0.89%, 1000=0.21%, 2000=0.01% > cpu : usr=9.58%, sys=1.15%, ctx=23883, majf=0, minf=2751023 > IO depths : 1=1.2%, 2=3.0%, 4=9.7%, 8=68.3%, 16=17.8%, 32=0.0%, > >=64=0.0% > submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, > >=64=0.0% > complete : 0=0.0%, 4=92.5%, 8=4.3%, 16=3.2%, 32=0.0%, 64=0.0%, > >=64=0.0% > issued : total=r=0/w=102400/d=0, short=r=0/w=0/d=0, > drop=r=0/w=0/d=0 > latency : target=0, window=0, percentile=100.00%, depth=16 > > Run status group 0 (all jobs): > WRITE: io=102400MB, aggrb=121882KB/s, minb=121882KB/s, > maxb=121882KB/s, mint=860318msec, maxt=860318msec > > Disk stats (read/write): > dm-1: ios=0/2072, merge=0/0, ticks=0/233, in_queue=233, util=0.01%, > aggrios=1/2249, aggrmerge=7/559, aggrticks=9/254, aggrin_queue=261, > aggrutil=0.01% > sda: ios=1/2249, merge=7/559, ticks=9/254, in_queue=261, util=0.01% > [root@rcprsdc1r72-01-ac rafaell]# > > Cheers, > Raf > > > -- > Rafael Lopez > Data Storage Administrator > Servers & Storage (eSolutions) > > > ________________________________________ > > PLEASE NOTE: The information contained in this electronic mail message is > intended only for the use of the designated recipient(s) named above. If the > reader of this message is not the intended recipient, you are hereby notified > that you have received this message in error and that any review, > dissemination, distribution, or copying of this message is strictly prohibited. If > you have received this communication in error, please notify the sender by > telephone or e-mail (as shown above) immediately and destroy any and all > copies of this message in your possession (whether hard copies or > electronically stored copies). > > > > > -- > Rafael Lopez > Data Storage Administrator > Servers & Storage (eSolutions) > +61 3 990 59118 > > > > > > -- > Rafael Lopez > Data Storage Administrator > Servers & Storage (eSolutions) > +61 3 990 59118 _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
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