ssh over WAN: TCP window too small

[Chris Stankevitz]

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(0x4,0x7fffffff6c70,0x4000)
>>>    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 really reading stdin in 4k blocks?  If so, that should be fixed)
>
> The read is making a call with 0x4000 = 16k buffer size, but it only receives 4k, probably because that is the max size of the pipe buffer.

In that example I used `ssh < /dev/null`.  I would have used 'dd 
if=/dev/zero bs=1m | ssh` but at the time I did not know about `foo | 
ktrace bar`.

Although if there is such a thing named "pipe buffer" I'm not sure it 
would have made a difference...

Chris