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 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 Best Regards, -- ryo li