Question performnace of SSH v1 vs SSH v2

Christopher Rapier rapier at psc.edu
Wed Mar 2 08:40:42 EST 2005


Markus Friedl wrote:
> On Tue, Mar 01, 2005 at 11:47:13AM -0500, Michael A Stevens wrote:
> 
>>There is also another subtle issue of how often should the window be 
>>polled. Polling the tcp window on a WINDOW_ADJUST message could prove to 
>>be costly if they happen very often.
> 
> 
> retrieving the tcp receive space once after connection
> establishment should be enough for almost all tcp
> stacks out there.

Actually, this isn't true. The Linux 2.6 kernel incorporate autotuning 
and enables it by default. The one problem is that the sysctl defaults 
to 128K at the moment (thats being worked on). It's also in the 2.4.27 
kernel albeit broken and off by default. However, the fixed version is 
in the developers tree and will be part of 2.4.29.

They've also had discussions with microsoft and a couple of other OSes. 
So yes, its only in one stack at the moment, but since its the linux 
stack its going to be common.




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