On Tue, Jun 30, 2020 at 12:07 AM Jens Axboe <axboe@xxxxxxxxx> wrote:
>
> On 6/28/20 1:27 PM, Yigal Korman wrote:
> > When enabled, some of the more dependency-heavy internal engines are
> > converted to "plugin" engines, i.e. they are built into separate object
> > files and are loaded by fio on demand.
> > This helps downstream distros package these engines separately and not
> > force a long list of package dependencies from the base fio package.
>
> How does this impact the performance of the engine? It'd be interesting
> to run a test with something ala:
>
> fio --name=test --ioengine=null --size=100g --rw=randread --norandommap --gtod_reduce=1
>
> with the current build, then apply these patches (and turn the null engine
> into an externally loadable engine, of course), and re-run the test case.
>
> For what it's worth, I like the change in general, as dependencies do
> pile on. But I'd like to ensure that we're not taking a performance hit
> for something like this.
Great to hear.
Here are the results of the run you suggested:
current build (statically linked) -
[root@host fio]# ./fio.static --name=test --ioengine=null --size=100g
--rw=randread --norandommap --gtod_reduce=1
test: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
4096B-4096B, ioengine=null, iodepth=1
fio-3.20-70-g9888
Starting 1 process
Jobs: 1 (f=1): [r(1)][100.0%][r=3910MiB/s][r=1001k IOPS][eta 00m:00s]
test: (groupid=0, jobs=1): err= 0: pid=155: Tue Jun 30 06:55:19 2020
read: IOPS=1000k, BW=3906MiB/s (4095MB/s)(100GiB/26219msec)
bw ( MiB/s): min= 3786, max= 3967, per=100.00%, avg=3909.96,
stdev=38.59, samples=52
iops : min=969293, max=1015596, avg=1000951.42,
stdev=9879.80, samples=52
cpu : usr=61.66%, sys=38.31%, ctx=103, majf=8, minf=5
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=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
issued rwts: total=26214400,0,0,0 short=0,0,0,0 dropped=0,0,0,0
latency : target=0, window=0, percentile=100.00%, depth=1
Run status group 0 (all jobs):
READ: bw=3906MiB/s (4095MB/s), 3906MiB/s-3906MiB/s
(4095MB/s-4095MB/s), io=100GiB (107GB), run=26219-26219msec
With patches applied[0] -
[root@host fio]# ./fio --name=test --ioengine=null --size=100g
--rw=randread --norandommap --gtod_reduce=1
test: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T)
4096B-4096B, ioengine=null, iodepth=1
fio-3.20-70-g9888
Starting 1 process
Jobs: 1 (f=1): [r(1)][100.0%][r=3905MiB/s][r=1000k IOPS][eta 00m:00s]
test: (groupid=0, jobs=1): err= 0: pid=158: Tue Jun 30 06:55:49 2020
read: IOPS=1006k, BW=3929MiB/s (4120MB/s)(100GiB/26060msec)
bw ( MiB/s): min= 3753, max= 3988, per=100.00%, avg=3933.86,
stdev=45.93, samples=52
iops : min=960962, max=1021038, avg=1007067.92,
stdev=11758.92, samples=52
cpu : usr=62.14%, sys=37.81%, ctx=117, majf=8, minf=5
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=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
complete : 0=0.0%, 4=0.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
issued rwts: total=26214400,0,0,0 short=0,0,0,0 dropped=0,0,0,0
latency : target=0, window=0, percentile=100.00%, depth=1
Run status group 0 (all jobs):
READ: bw=3929MiB/s (4120MB/s), 3929MiB/s-3929MiB/s
(4120MB/s-4120MB/s), io=100GiB (107GB), run=26060-26060msec
I wasn't expecting dynamic linking to have a performance impact and
the results seem to agree.
Thanks!
[0] branch with the null engine converted to dynamic:
https://github.com/ykorman/fio/tree/devel
Yigal
>
>
> --
> Jens Axboe
>
