increasing the write block size for high latency

[Adam Edgar]

On Jul 26, 2014, at 2:53 PM, Dan Stromberg <drsalists at gmail.com> wrote:

> On Tue, Jul 8, 2014 at 8:07 AM, Adam Edgar <aedgar at research.att.com> wrote:
>> It seems the issue is indeed in the ssh layer. scp has the same issue and some work has been done in “fixing” that:
>> 
>> http://www.psc.edu/index.php/hpn-ssh
>> 
>> From the papers abstract:
>> 
>>        SCP and the underlying SSH2 protocol implementation in OpenSSH is network performance limited by statically defined internal flow control buffers. These buffers often end up acting as a bottleneck for network throughput of SCP, especially on long and high bandwith network links.
> 
> It's a bit hard to believe that PSC's performance patches still
> haven't been merged.
> 

Not really. The concern has to be about using malloc. You can open lots of security holes if you are not careful with dynamic allocation. Larger static buffers would be easier to check for exploits but would limit the scalability.

ASE