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Date:      Fri, 11 Aug 2023 12:27:04 -0400
From:      Joe Schaefer <joesuf4@gmail.com>
To:        freebsd-hackers@freebsd.org
Subject:   Re: can sftp be made multi-threaded?
Message-ID:  <CAOzHqc%2BGYsS=gCGfHC%2BxLK42hnK95tea_7qiKgUDJO=bF3Ys9A@mail.gmail.com>
In-Reply-To: <CAOzHqcK5DUj0-b%2BP_sqPyC7NknHKaS1_fNcnTWKjde-SYn9QSA@mail.gmail.com>
References:  <ZNOJUfIHGtY9lLpg@int21h> <202308111121.37BBLX0J064263@donotpassgo.dyslexicfish.net> <ZNZBVf1CuI35PyBf@int21h> <CAOzHqcK5DUj0-b%2BP_sqPyC7NknHKaS1_fNcnTWKjde-SYn9QSA@mail.gmail.com>

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If it=E2=80=99s just a single file, split it into chunks.

On Fri, Aug 11, 2023 at 12:25 PM Joe Schaefer <joesuf4@gmail.com> wrote:

> Why don=E2=80=99t you just use xargs -P until you=E2=80=99ve exhausted yo=
ur CPU capacity?
>
> On Fri, Aug 11, 2023 at 10:10 AM void <void@f-m.fm> wrote:
>
>> On Fri, Aug 11, 2023 at 12:21:33PM +0100, Jamie Landeg-Jones wrote:
>>
>> >rsync just spawns an ssh command, so would probably behave similarly.
>>
>> I'm hoping that rsync will spawn many ssh. Need to look at max sessions
>> on both ends of the connection.
>>
>> Since encountering the described problem, the person at the other
>> end is away for the week so have not been able to test thoroughly.
>> What I have been able to test shows that there is spiky latency
>> in the connection, as well as slow speed, single-threaded.
>>
>> >Another thing, scp transfers from my test Rpi2 are much slower than the
>> network
>> >can handle due to the CPU use, which hits 100% on one cpu whilst it's
>> running.
>> >So, check that CPU isn't the bottleneck too.
>>
>> Yup. That won't be happening here. Dual xenon with 56 cores at remote
>> end and same (but with 32 cores) at this end
>>
>> >As for the speed, I just tested sftp to transfer a file of random data,
>> 2 GB in
>> >size from one FreeBSD box in London to another in France:
>> >
>> >The final result was:
>> >
>> > 100% 2000MB  43.5MB/s   00:46  (Note, that's MegaBYTES/s)
>>
>> I ran a similar test.
>> Sending system is on synchronous gigabit fibre on US east coast,
>> receiving system is near London on 110/21 fibre (so, gigabit in the
>> sending
>> direction):
>>
>> 100% 2000MB   7.2MB/s   04:36
>>
>> using rsync -azP : 2,097,152,000 100%    6.81MB/s    0:04:53 (xfr#1,
>> to-chk=3D0/1)
>>
>> the speed fluctulates a lot. Both systems are quiet in a network and OS
>> sense
>> for the duration of the test.
>>
>> >The London box is pretty old, and is a virtual host scheduled to be
>> decomissioned.
>> >It is running an old openssl 1.X, openssh 8.8 and is a single core
>> 2.4Ghz amd64 box.
>> >
>> >The France box is a 4 core bare metal 3.1Ghz and64 running openssh 9.2
>> and openssl 1.1.1
>>
>> both ends here are running very recent -current, so ssl/ssh is
>> OpenSSH_9.3p1, OpenSSL 3.0.9 30 May 2023
>>
>> >Anything more I can tell you that may help?
>>
>> Thanks very much for your input. I'm certain it's not a freebsd problem.
>>
>> --
>>
>>

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<div dir=3D"auto">If it=E2=80=99s just a single file, split it into chunks.=
</div><div><br><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_a=
ttr">On Fri, Aug 11, 2023 at 12:25 PM Joe Schaefer &lt;<a href=3D"mailto:jo=
esuf4@gmail.com">joesuf4@gmail.com</a>&gt; wrote:<br></div><blockquote clas=
s=3D"gmail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;pad=
ding-left:1ex"><div dir=3D"auto">Why don=E2=80=99t you just use xargs -P un=
til you=E2=80=99ve exhausted your CPU capacity?</div><div dir=3D"auto"><br>=
</div><div><div class=3D"gmail_quote"><div dir=3D"ltr" class=3D"gmail_attr"=
>On Fri, Aug 11, 2023 at 10:10 AM void &lt;<a href=3D"mailto:void@f-m.fm" t=
arget=3D"_blank">void@f-m.fm</a>&gt; wrote:<br></div><blockquote class=3D"g=
mail_quote" style=3D"margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-l=
eft:1ex">On Fri, Aug 11, 2023 at 12:21:33PM +0100, Jamie Landeg-Jones wrote=
:<br>
<br>
&gt;rsync just spawns an ssh command, so would probably behave similarly.<b=
r>
<br>
I&#39;m hoping that rsync will spawn many ssh. Need to look at max sessions=
 <br>
on both ends of the connection.<br>
<br>
Since encountering the described problem, the person at the other<br>
end is away for the week so have not been able to test thoroughly.<br>
What I have been able to test shows that there is spiky latency<br>
in the connection, as well as slow speed, single-threaded.<br>
<br>
&gt;Another thing, scp transfers from my test Rpi2 are much slower than the=
 network<br>
&gt;can handle due to the CPU use, which hits 100% on one cpu whilst it&#39=
;s running.<br>
&gt;So, check that CPU isn&#39;t the bottleneck too.<br>
<br>
Yup. That won&#39;t be happening here. Dual xenon with 56 cores at remote<b=
r>
end and same (but with 32 cores) at this end<br>
<br>
&gt;As for the speed, I just tested sftp to transfer a file of random data,=
 2 GB in<br>
&gt;size from one FreeBSD box in London to another in France:<br>
&gt;<br>
&gt;The final result was:<br>
&gt;<br>
&gt; 100% 2000MB=C2=A0 43.5MB/s=C2=A0 =C2=A000:46=C2=A0 (Note, that&#39;s M=
egaBYTES/s)<br>
<br>
I ran a similar test.<br>
Sending system is on synchronous gigabit fibre on US east coast,<br>
receiving system is near London on 110/21 fibre (so, gigabit in the sending=
<br>
direction):<br>
<br>
100% 2000MB=C2=A0 =C2=A07.2MB/s=C2=A0 =C2=A004:36<br>
<br>
using rsync -azP : 2,097,152,000 100%=C2=A0 =C2=A0 6.81MB/s=C2=A0 =C2=A0 0:=
04:53 (xfr#1, to-chk=3D0/1)<br>
<br>
the speed fluctulates a lot. Both systems are quiet in a network and OS sen=
se<br>
for the duration of the test.<br>
<br>
&gt;The London box is pretty old, and is a virtual host scheduled to be dec=
omissioned.<br>
&gt;It is running an old openssl 1.X, openssh 8.8 and is a single core 2.4G=
hz amd64 box.<br>
&gt;<br>
&gt;The France box is a 4 core bare metal 3.1Ghz and64 running openssh 9.2 =
and openssl 1.1.1<br>
<br>
both ends here are running very recent -current, so ssl/ssh is <br>
OpenSSH_9.3p1, OpenSSL 3.0.9 30 May 2023<br>
<br>
&gt;Anything more I can tell you that may help?<br>
<br>
Thanks very much for your input. I&#39;m certain it&#39;s not a freebsd pro=
blem.<br>
<br>
-- <br>
<br>
</blockquote></div></div>
</blockquote></div></div>

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