The dax window I set is not very large (for example, 512MB). I am worried that the setting is too large. After a lot of VM workloads are started, it will take up a lot of memory (I know it is a mapping technology). If this setting is large, will it be a problem? , Such as 10G, 50G? The following is my test performance data, it seems that the results are quite different, I don’t know why? fio --name=small-file-multi-read --directory=/usr/share/nginx/html \ --rw=randread --file_service_type=sequential \ --bs=4k --filesize=10M --nrfiles=100 \ --runtime=60 --time_based --numjobs=1 ... small-file-multi-read: (groupid=0, jobs=1): err= 0: pid=190: Mon Jul 5 07:05:18 2021 read: IOPS=12.0k, BW=46.0MiB/s (49.2MB/s)(212MiB/4505msec) fio --name=5G-bigfile-rand-read --directory=/usr/share/nginx/html --rw=randread --size=5G --bs=4k --runtime=60 --time_based --numjobs=1 ... 5G-bigfile-rand-read: (groupid=0, jobs=1): err= 0: pid=184: Mon Jul 5 06:57:08 2021 read: IOPS=1255, BW=5024KiB/s (5144kB/s)(294MiB/60002msec) 在 2021/7/7 下午8:44，“Vivek Goyal”<vgoyal@redhat.com> 写入: On Fri, Jul 02, 2021 at 10:57:43AM +0200, Fabiano Fidêncio wrote: > Ryo Li, > > On Thu, Jul 1, 2021 at 11:49 AM 李瑞友 <liruiyou@huayun.com> wrote: > > > > Hi guys > > > > I want to build a test scenario to see the difference in performance between the size of DAX windows and the size of read files. But it's not that I don't know how to build. > > > > I tried the following two methods, but it seems that the performance results are similar I am not sure what's the expectation. Why changing file size should change the throughput significantly. If DAX window is big enough to accomodate both small file and large file completely, then I/O rate will probably be same/similar. Thanks Vivek > > > > > > > > fio -filename=/usr/share/nginx/html/400MBfile --rw=randread --loops=10 --group_reporting --name=400MBfile > > > > > > > > fio -filename=/usr/share/nginx/html/5Gfile --rw=randread -bs=16k --group_reporting --name=5Gfile > > > > > > > > sh-4.4# fio -filename=/usr/share/nginx/html/5Gfile --rw=randread -bs=16k --group_reporting --name=5Gfile > > > > 5Gfile: (g=0): rw=randread, bs=(R) 16.0KiB-16.0KiB, (W) 16.0KiB-16.0KiB, (T) 16.0KiB-16.0KiB, ioengine=psync, iodepth=1 > > > > fio-3.19 > > > > Starting 1 process > > > > Jobs: 1 (f=1): [r(1)][100.0%][r=148MiB/s][r=9450 IOPS][eta 00m:00s] > > > > 5Gfile: (groupid=0, jobs=1): err= 0: pid=139: Thu Jul 1 09:38:07 2021 > > > > read: IOPS=9931, BW=155MiB/s (163MB/s)(5120MiB/32993msec) > > > > clat (usec): min=52, max=18734, avg=95.79, stdev=69.49 > > > > lat (usec): min=53, max=18735, avg=96.47, stdev=69.53 > > > > clat percentiles (usec): > > > > | 1.00th=[ 61], 5.00th=[ 64], 10.00th=[ 66], 20.00th=[ 71], > > > > | 30.00th=[ 75], 40.00th=[ 79], 50.00th=[ 82], 60.00th=[ 88], > > > > | 70.00th=[ 97], 80.00th=[ 114], 90.00th=[ 141], 95.00th=[ 163], > > > > | 99.00th=[ 235], 99.50th=[ 293], 99.90th=[ 734], 99.95th=[ 807], > > > > | 99.99th=[ 1287] > > > > bw ( KiB/s): min=87471, max=191168, per=100.00%, avg=159511.97, stdev=18299.18, samples=65 > > > > iops : min= 5466, max=11948, avg=9969.48, stdev=1143.77, samples=65 > > > > lat (usec) : 100=72.93%, 250=26.28%, 500=0.52%, 750=0.19%, 1000=0.06% > > > > lat (msec) : 2=0.01%, 4=0.01%, 10=0.01%, 20=0.01% > > > > cpu : usr=6.04%, sys=46.45%, ctx=329379, majf=1, minf=13 > > > > 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 rwts: total=327680,0,0,0 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=155MiB/s (163MB/s), 155MiB/s-155MiB/s (163MB/s-163MB/s), io=5120MiB (5369MB), run=32993-32993msec > > > I've looped in some folks from Red Hat and Intel who have been working > with virtiofs, either on performance, on integration, or on virtiofs > itself. > I think they'll be able to provide you with some valuable feedback. > > Please, mind that due to July 4th I think folks from the US may be off > for the next few days. > > Best Regards, > -- > Fabiano Fidêncio >