Re: measuring swap partition speed

Hi Mark & Warner,

I tried using fio with Warner's suggestions as a template, and
pasted the results in the latter part of this message.

On Thu, 21 Dec 2023, at 21:03, Mark Millard wrote:

> # sysctl vm.stats.vm.v_page_size
> vm.stats.vm.v_page_size: 4096

Here, this setting is:
# sysctl vm.stats.vm.v_page_size
vm.stats.vm.v_page_size: 4096

> # sysctl vm.phys_pager_cluster
> vm.phys_pager_cluster: 1024

It is 1024 here, too.

Only the one usb3 port is occupied.

fio output follows. No idea yet if the settings used are suitable for this context
and would welcome suggestions. I think --filename can be a device? Output suggests
it used hw.ncpu instead of --numjobs=8

~~~~~~~
# fio --name=randread --ioengine=posixaio --rw=randread --direct=1 --bs=8k --refill_buffers --norandommap --randrepeat=0 --iodepth=32 --numjobs=8 --runtime=60 --group_reporting --thread --size=2048M
randread: (g=0): rw=randread, bs=(R) 8192B-8192B, (W) 8192B-8192B, (T) 8192B-8192B, ioengine=posixaio, iodepth=32
...
fio-3.36
Starting 8 threads
randread: Laying out IO file (1 file / 2048MiB)
randread: Laying out IO file (1 file / 2048MiB)
randread: Laying out IO file (1 file / 2048MiB)
randread: Laying out IO file (1 file / 2048MiB)
randread: Laying out IO file (1 file / 2048MiB)
randread: Laying out IO file (1 file / 2048MiB)
randread: Laying out IO file (1 file / 2048MiB)
randread: Laying out IO file (1 file / 2048MiB)
Jobs: 4 (f=4): [_(1),r(2),_(2),r(1),_(1),r(1)][21.2%][r=288KiB/s][r=36 IOPS][eta 04m:05s]
randread: (groupid=0, jobs=8): err= 0: pid=135125: Thu Dec 21 16:43:00 2023
  read: IOPS=43, BW=351KiB/s (359kB/s)(22.6MiB/65986msec)
    slat (nsec): min=889, max=1948.6k, avg=4172.45, stdev=36488.07
    clat (msec): min=1108, max=11660, avg=5644.23, stdev=1282.12
     lat (msec): min=1108, max=11660, avg=5644.24, stdev=1282.12
    clat percentiles (msec):
     |  1.00th=[ 1183],  5.00th=[ 3171], 10.00th=[ 4933], 20.00th=[ 5269],
     | 30.00th=[ 5470], 40.00th=[ 5604], 50.00th=[ 5738], 60.00th=[ 5873],
     | 70.00th=[ 5940], 80.00th=[ 6074], 90.00th=[ 6342], 95.00th=[ 6812],
     | 99.00th=[10671], 99.50th=[10939], 99.90th=[11610], 99.95th=[11610],
     | 99.99th=[11610]
   bw (  KiB/s): min=  208, max= 3760, per=100.00%, avg=1535.05, stdev=128.23, samples=245
   iops        : min=   26, max=  470, avg=191.88, stdev=16.03, samples=245
  lat (msec)   : 2000=3.25%, >=2000=96.75%
  cpu          : usr=0.00%, sys=0.12%, ctx=22712, majf=0, minf=0
  IO depths    : 1=0.3%, 2=0.6%, 4=1.1%, 8=4.9%, 16=69.6%, 32=23.6%, >=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=94.7%, 8=2.9%, 16=1.5%, 32=0.9%, 64=0.0%, >=64=0.0%
     issued rwts: total=2895,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=32

Run status group 0 (all jobs):
   READ: bw=351KiB/s (359kB/s), 351KiB/s-351KiB/s (359kB/s-359kB/s), io=22.6MiB (23.7MB), run=65986-65986msec
# 
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