Starting with Solaris 11.4 you got a new interface for device latency without using dtrace. The information was always there but now you can use a “human readable” command. That might bring easier understanding and analyzing the disk subsystem.
I ran an IO calibrate in a 18c database which resides on NVMe flash drives:
root@t7primary01:~# iostat -x -L c5t1d0 c1t1d0 1
extended device statistics
device r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b
blkdev2 29.9 13.1 185.7 81.4 0.0 0.0 0.0 0.1 0 0
latency range count density distribution
<4us 0 0.00% 0.00%
4-8us 3527 0.02% 0.02%
8-16us 1224166 5.74% 5.76%
16-32us 4020858 18.85% 24.61%
32-64us 1225365 5.75% 30.35%
64-128us 13243355 62.10% 92.45%
128-256us 1561222 7.32% 99.77%
256-512us 34758 0.16% 99.93%
512-1024us 4642 0.02% 99.96%
1-2ms 3624 0.02% 99.97%
2-4ms 5758 0.03% 100.00%
4-8ms 97 0.00% 100.00%
8-16ms 33 0.00% 100.00%
>16ms 0 0.00% 100.00%
total 21327405
blkdev3 32.0 14.0 198.5 86.8 0.0 0.0 0.0 0.1 0 0
latency range count density distribution
<4us 0 0.00% 0.00%
4-8us 2848 0.01% 0.01%
8-16us 1280834 5.62% 5.64%
16-32us 4197957 18.44% 24.07%
32-64us 1355014 5.95% 30.02%
64-128us 14167408 62.22% 92.24%
128-256us 1734203 7.62% 99.86%
256-512us 29629 0.13% 99.99%
512-1024us 895 0.00% 99.99%
1-2ms 614 0.00% 100.00%
2-4ms 939 0.00% 100.00%
4-8ms 104 0.00% 100.00%
8-16ms 27 0.00% 100.00%
>16ms 0 0.00% 100.00%
extended device statistics
device r/s w/s kr/s kw/s wait actv wsvc_t asvc_t %w %b
blkdev2 49234.1 1.0 307781.4 20.0 0.0 5.4 0.0 0.1 0 20
latency range count density distribution
<16us 0 0.00% 0.00%
16-32us 1 0.00% 0.00%
32-64us 21 0.04% 0.05%
64-128us 42324 88.06% 88.10%
128-256us 5647 11.75% 99.85%
256-512us 67 0.14% 99.99%
512-1024us 1 0.00% 99.99%
1-2ms 1 0.00% 100.00%
2-4ms 2 0.00% 100.00%
>4ms 0 0.00% 100.00%
total 48064
blkdev3 52145.2 0.0 325741.9 0.0 0.0 5.7 0.0 0.1 0 18
latency range count density distribution
<32us 0 0.00% 0.00%
32-64us 28 0.05% 0.05%
64-128us 44430 87.26% 87.31%
128-256us 6374 12.52% 99.83%
256-512us 84 0.16% 99.99%
512-1024us 3 0.01% 100.00%
>1024us 0 0.00% 100.00%
total 50919
That’s a nice overview…