On 8/25/15 3:47 PM, Chris Stankevitz wrote:
Can anyone explain my abysmally small TCP window?
So I believe this is the story:
1. openssh limits the size of some outgoing buffer to 65KB
2. openssh/HPN tries to improve on this by increasing the size of the
outgoing buffer to match getsockopt(S
On 8/27/15 6:14 AM, Kurt Lidl wrote:
# tcp options for long-haul speedups
kern.ipc.maxsockbuf=4194304 # (2 * default 2097152)
net.inet.tcp.mssdflt=1448 # (default 576)
net.inet.tcp.sendbuf_max=4194304# (2 * default 2097152)
net.inet.tcp.recvbuf_max=4194304
On 8/26/15 5:46 PM, David DeSimone wrote:
On 8/26/15 1:24 AM, John-Mark Gurney wrote:
94146 ssh 6.686140 CALL read(0x4,0x7fff6c70,0x4000)
94146 ssh 6.686154 GIO fd 4 read 4096 bytes
[ read of stdin (/dev/zero) snipped)
It would be interesting to know how long from th
John-Mark,
I'm going to rearrange the conversation a bit in the quotes below:
On 8/26/15 3:32 PM, John-Mark Gurney wrote:
So, I looked at what getsockopt SO_RCVBUF returns, and it returns:
case SO_RCVBUF:
optval = so->so_rcv.sb_hiwat;
Which is NOT S-
On Tue, Aug 25, 2015 at 2:12 PM, Chris Stankevitz
wrote:
> On 8/25/15 4:11 PM, Bjoern A. Zeeb wrote:
>
>>
>> On 25 Aug 2015, at 22:47 , Chris Stankevitz wrote:
>>>
>>> Can anyone recommend some tools/tricks to figure out what in FreeBSD
>>> and/or
>>>
>> >> base SSH is limiting the send/recv buf
Chris Stankevitz wrote:
Hi,
# cat /dev/urandom | ssh root at host 'cat > /dev/null'
I use the above ssh command over a high-BDP WAN link (80 ms @ 100 Mbps).
tcpdump shows I am TCP window limited to 64 KBytes (yielding 5 Mbps).
iperf with default options gets the window opened to 500 KBytes
On 8/26/15 1:24 AM, John-Mark Gurney wrote:
> > 94146 ssh 6.686140 CALL read(0x4,0x7fff6c70,0x4000)
> > 94146 ssh 6.686154 GIO fd 4 read 4096 bytes
> >[ read of stdin (/dev/zero) snipped)
>
> It would be interesting to know how long from the read of stdin (and is
> it reall
Hi,
> On 26 Aug 2015, at 08:47, Chris Stankevitz wrote:
>
> Hi,
>
> # cat /dev/urandom | ssh root@host 'cat > /dev/null'
>
> I use the above ssh command over a high-BDP WAN link (80 ms @ 100 Mbps).
> tcpdump shows I am TCP window limited to 64 KBytes (yielding 5 Mbps). iperf
> with default
Chris Stankevitz wrote this message on Wed, Aug 26, 2015 at 14:30 -0700:
> Thanks again. I appreciate you teaching me "how to fish". I basically
> spent all morning reading kdump output.
No worries, glad you're learning...
> On 8/26/15 1:24 AM, John-Mark Gurney wrote:
> > It really looks like
On Wed, Aug 26, 2015 at 02:30:07PM -0700, Chris Stankevitz wrote:
> > ktrace -i ssh ...
>
> Thank you, this is awesome. Is there a way for me to ktrace 'b' in this
> example: `a | b | c`? I tried `ktrace a | b | c` and `ktrace test.sh`
> (which included a|b|c) but neither seemed to work. I'm
John-Mark,
Thanks again. I appreciate you teaching me "how to fish". I basically
spent all morning reading kdump output.
On 8/26/15 1:24 AM, John-Mark Gurney wrote:
> It really looks like we should set TCPRcvBufPoll by default on
> FreeBSD...
According to /etc/ssh/sshd_config, TCPRcvBufPoll
Chris Stankevitz wrote:
# cat /dev/urandom | ssh root@host 'cat > /dev/null'
I use the above ssh command over a high-BDP WAN link (80 ms @ 100
Mbps).
tcpdump shows I am TCP window limited to 64 KBytes (yielding 5 Mbps).
iperf with default options gets the window opened to 500 KBytes
(yieldin
Chris Stankevitz wrote this message on Tue, Aug 25, 2015 at 19:55 -0700:
> John-Mark,
>
> Thank you for your reply.
>
> On 8/25/15 6:03 PM, John-Mark Gurney wrote:
> > Chris Stankevitz wrote this message on Tue, Aug 25, 2015 at 15:47 -0700:
> >> # cat /dev/urandom | ssh root@host 'cat > /dev/null
John-Mark,
Thank you for your reply.
On 8/25/15 6:03 PM, John-Mark Gurney wrote:
Chris Stankevitz wrote this message on Tue, Aug 25, 2015 at 15:47 -0700:
# cat /dev/urandom | ssh root@host 'cat > /dev/null'
Don't use this for testing... use /dev/zero or some other device
that can produce dat
Chris Stankevitz wrote this message on Tue, Aug 25, 2015 at 15:47 -0700:
> # cat /dev/urandom | ssh root@host 'cat > /dev/null'
Don't use this for testing... use /dev/zero or some other device
that can produce data faster than this...
> I use the above ssh command over a high-BDP WAN link (80 ms
On 8/25/15 4:11 PM, Bjoern A. Zeeb wrote:
On 25 Aug 2015, at 22:47 , Chris Stankevitz wrote:
Can anyone recommend some tools/tricks to figure out what in FreeBSD and/or
>> base SSH is limiting the send/recv buffer and/or TCP window?
if you have the memory, try these sysctls:
kern.ipc.maxs
> On 25 Aug 2015, at 22:47 , Chris Stankevitz wrote:
>
> Hi,
>
> # cat /dev/urandom | ssh root@host 'cat > /dev/null'
>
> I use the above ssh command over a high-BDP WAN link (80 ms @ 100 Mbps).
> tcpdump shows I am TCP window limited to 64 KBytes (yielding 5 Mbps). iperf
> with default op
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