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Date:      Sat, 23 Dec 2023 14:19:28 -0700
From:      Warner Losh <imp@bsdimp.com>
To:        void <void@f-m.fm>
Cc:        freebsd-fs <freebsd-fs@freebsd.org>
Subject:   Re: measuring swap partition speed
Message-ID:  <CANCZdfpbuOo4qpjifcmq8i8Kz_7a4DWcVNkqJbMEwnkLA-W6Lw@mail.gmail.com>
In-Reply-To: <2dcc21bb-f446-41fa-871b-2c37cdf9afe0@app.fastmail.com>
References:  <A6B49CB2-2EEC-4F1F-8777-D7EF65C71E5E.ref@yahoo.com> <A6B49CB2-2EEC-4F1F-8777-D7EF65C71E5E@yahoo.com> <2dcc21bb-f446-41fa-871b-2c37cdf9afe0@app.fastmail.com>

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On Thu, Dec 21, 2023 at 5:20=E2=80=AFPM void <void@f-m.fm> wrote:

> 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 thi=
s
> context
> and would welcome suggestions. I think --filename can be a device? Output
> suggests
> it used hw.ncpu instead of --numjobs=3D8
>
> ~~~~~~~
> # fio --name=3Drandread --ioengine=3Dposixaio --rw=3Drandread --direct=3D=
1 --bs=3D8k
> --refill_buffers --norandommap --randrepeat=3D0 --iodepth=3D32 --numjobs=
=3D8
> --runtime=3D60 --group_reporting --thread --size=3D2048M
> randread: (g=3D0): rw=3Drandread, bs=3D(R) 8192B-8192B, (W) 8192B-8192B, =
(T)
> 8192B-8192B, ioengine=3Dposixaio, iodepth=3D32
> ..
> 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=3D4): [_(1),r(2),_(2),r(1),_(1),r(1)][21.2%][r=3D288KiB/s][r=
=3D36
> IOPS][eta 04m:05s]
> randread: (groupid=3D0, jobs=3D8): err=3D 0: pid=3D135125: Thu Dec 21 16:=
43:00 2023
>   read: IOPS=3D43, BW=3D351KiB/s (359kB/s)(22.6MiB/65986msec)
>     slat (nsec): min=3D889, max=3D1948.6k, avg=3D4172.45, stdev=3D36488.0=
7
>     clat (msec): min=3D1108, max=3D11660, avg=3D5644.23, stdev=3D1282.12
>      lat (msec): min=3D1108, max=3D11660, avg=3D5644.24, stdev=3D1282.12
>     clat percentiles (msec):
>      |  1.00th=3D[ 1183],  5.00th=3D[ 3171], 10.00th=3D[ 4933], 20.00th=
=3D[ 5269],
>      | 30.00th=3D[ 5470], 40.00th=3D[ 5604], 50.00th=3D[ 5738], 60.00th=
=3D[ 5873],
>      | 70.00th=3D[ 5940], 80.00th=3D[ 6074], 90.00th=3D[ 6342], 95.00th=
=3D[ 6812],
>      | 99.00th=3D[10671], 99.50th=3D[10939], 99.90th=3D[11610], 99.95th=
=3D[11610],
>      | 99.99th=3D[11610]
>    bw (  KiB/s): min=3D  208, max=3D 3760, per=3D100.00%, avg=3D1535.05,
> stdev=3D128.23, samples=3D245
>    iops        : min=3D   26, max=3D  470, avg=3D191.88, stdev=3D16.03, s=
amples=3D245
>   lat (msec)   : 2000=3D3.25%, >=3D2000=3D96.75%
>   cpu          : usr=3D0.00%, sys=3D0.12%, ctx=3D22712, majf=3D0, minf=3D=
0
>   IO depths    : 1=3D0.3%, 2=3D0.6%, 4=3D1.1%, 8=3D4.9%, 16=3D69.6%, 32=
=3D23.6%,
> >=3D64=3D0.0%
>      submit    : 0=3D0.0%, 4=3D100.0%, 8=3D0.0%, 16=3D0.0%, 32=3D0.0%, 64=
=3D0.0%,
> >=3D64=3D0.0%
>      complete  : 0=3D0.0%, 4=3D94.7%, 8=3D2.9%, 16=3D1.5%, 32=3D0.9%, 64=
=3D0.0%,
> >=3D64=3D0.0%
>      issued rwts: total=3D2895,0,0,0 short=3D0,0,0,0 dropped=3D0,0,0,0
>      latency   : target=3D0, window=3D0, percentile=3D100.00%, depth=3D32
>
> Run status group 0 (all jobs):
>    READ: bw=3D351KiB/s (359kB/s), 351KiB/s-351KiB/s (359kB/s-359kB/s),
> io=3D22.6MiB (23.7MB), run=3D65986-65986msec
> #
>

5s+ of latency on the average, max latency of 12s!  Woof. No wonder you
hate life.

Warner

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<div dir=3D"ltr"><div dir=3D"ltr"><br></div><br><div class=3D"gmail_quote">=
<div dir=3D"ltr" class=3D"gmail_attr">On Thu, Dec 21, 2023 at 5:20=E2=80=AF=
PM void &lt;<a href=3D"mailto:void@f-m.fm">void@f-m.fm</a>&gt; wrote:<br></=
div><blockquote class=3D"gmail_quote" style=3D"margin:0px 0px 0px 0.8ex;bor=
der-left:1px solid rgb(204,204,204);padding-left:1ex">Hi Mark &amp; Warner,=
<br>
<br>
I tried using fio with Warner&#39;s suggestions as a template, and<br>
pasted the results in the latter part of this message.<br>
<br>
On Thu, 21 Dec 2023, at 21:03, Mark Millard wrote:<br>
<br>
&gt; # sysctl vm.stats.vm.v_page_size<br>
&gt; vm.stats.vm.v_page_size: 4096<br>
<br>
Here, this setting is:<br>
# sysctl vm.stats.vm.v_page_size<br>
vm.stats.vm.v_page_size: 4096<br>
<br>
&gt; # sysctl vm.phys_pager_cluster<br>
&gt; vm.phys_pager_cluster: 1024<br>
<br>
It is 1024 here, too.<br>
<br>
Only the one usb3 port is occupied.<br>
<br>
fio output follows. No idea yet if the settings used are suitable for this =
context<br>
and would welcome suggestions. I think --filename can be a device? Output s=
uggests<br>
it used hw.ncpu instead of --numjobs=3D8<br>
<br>
~~~~~~~<br>
# fio --name=3Drandread --ioengine=3Dposixaio --rw=3Drandread --direct=3D1 =
--bs=3D8k --refill_buffers --norandommap --randrepeat=3D0 --iodepth=3D32 --=
numjobs=3D8 --runtime=3D60 --group_reporting --thread --size=3D2048M<br>
randread: (g=3D0): rw=3Drandread, bs=3D(R) 8192B-8192B, (W) 8192B-8192B, (T=
) 8192B-8192B, ioengine=3Dposixaio, iodepth=3D32<br>
..<br>
fio-3.36<br>
Starting 8 threads<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
randread: Laying out IO file (1 file / 2048MiB)<br>
Jobs: 4 (f=3D4): [_(1),r(2),_(2),r(1),_(1),r(1)][21.2%][r=3D288KiB/s][r=3D3=
6 IOPS][eta 04m:05s]<br>
randread: (groupid=3D0, jobs=3D8): err=3D 0: pid=3D135125: Thu Dec 21 16:43=
:00 2023<br>
=C2=A0 read: IOPS=3D43, BW=3D351KiB/s (359kB/s)(22.6MiB/65986msec)<br>
=C2=A0 =C2=A0 slat (nsec): min=3D889, max=3D1948.6k, avg=3D4172.45, stdev=
=3D36488.07<br>
=C2=A0 =C2=A0 clat (msec): min=3D1108, max=3D11660, avg=3D5644.23, stdev=3D=
1282.12<br>
=C2=A0 =C2=A0 =C2=A0lat (msec): min=3D1108, max=3D11660, avg=3D5644.24, std=
ev=3D1282.12<br>
=C2=A0 =C2=A0 clat percentiles (msec):<br>
=C2=A0 =C2=A0 =C2=A0|=C2=A0 1.00th=3D[ 1183],=C2=A0 5.00th=3D[ 3171], 10.00=
th=3D[ 4933], 20.00th=3D[ 5269],<br>
=C2=A0 =C2=A0 =C2=A0| 30.00th=3D[ 5470], 40.00th=3D[ 5604], 50.00th=3D[ 573=
8], 60.00th=3D[ 5873],<br>
=C2=A0 =C2=A0 =C2=A0| 70.00th=3D[ 5940], 80.00th=3D[ 6074], 90.00th=3D[ 634=
2], 95.00th=3D[ 6812],<br>
=C2=A0 =C2=A0 =C2=A0| 99.00th=3D[10671], 99.50th=3D[10939], 99.90th=3D[1161=
0], 99.95th=3D[11610],<br>
=C2=A0 =C2=A0 =C2=A0| 99.99th=3D[11610]<br>
=C2=A0 =C2=A0bw (=C2=A0 KiB/s): min=3D=C2=A0 208, max=3D 3760, per=3D100.00=
%, avg=3D1535.05, stdev=3D128.23, samples=3D245<br>
=C2=A0 =C2=A0iops=C2=A0 =C2=A0 =C2=A0 =C2=A0 : min=3D=C2=A0 =C2=A026, max=
=3D=C2=A0 470, avg=3D191.88, stdev=3D16.03, samples=3D245<br>
=C2=A0 lat (msec)=C2=A0 =C2=A0: 2000=3D3.25%, &gt;=3D2000=3D96.75%<br>
=C2=A0 cpu=C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 : usr=3D0.00%, sys=3D0.12%, ct=
x=3D22712, majf=3D0, minf=3D0<br>
=C2=A0 IO depths=C2=A0 =C2=A0 : 1=3D0.3%, 2=3D0.6%, 4=3D1.1%, 8=3D4.9%, 16=
=3D69.6%, 32=3D23.6%, &gt;=3D64=3D0.0%<br>
=C2=A0 =C2=A0 =C2=A0submit=C2=A0 =C2=A0 : 0=3D0.0%, 4=3D100.0%, 8=3D0.0%, 1=
6=3D0.0%, 32=3D0.0%, 64=3D0.0%, &gt;=3D64=3D0.0%<br>
=C2=A0 =C2=A0 =C2=A0complete=C2=A0 : 0=3D0.0%, 4=3D94.7%, 8=3D2.9%, 16=3D1.=
5%, 32=3D0.9%, 64=3D0.0%, &gt;=3D64=3D0.0%<br>
=C2=A0 =C2=A0 =C2=A0issued rwts: total=3D2895,0,0,0 short=3D0,0,0,0 dropped=
=3D0,0,0,0<br>
=C2=A0 =C2=A0 =C2=A0latency=C2=A0 =C2=A0: target=3D0, window=3D0, percentil=
e=3D100.00%, depth=3D32<br>
<br>
Run status group 0 (all jobs):<br>
=C2=A0 =C2=A0READ: bw=3D351KiB/s (359kB/s), 351KiB/s-351KiB/s (359kB/s-359k=
B/s), io=3D22.6MiB (23.7MB), run=3D65986-65986msec<br>
#<br></blockquote><div><br></div><div>5s+ of latency on the average, max la=
tency of 12s!=C2=A0 Woof. No wonder you hate life.</div><div><br></div><div=
>Warner</div></div></div>

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