very poor cygwin scp performance in some situations

[Pedro Inacio]

Hello,

I've initiated the post "select() too slow".
The example I've done was a non-blocking tcp echo_server.c and how  
slow it was on linux compared with cygwin.
In fact after activation oh tcp_nodelay option the times were similar.

Meanwhile I've done another test, I've added ssl on top of that  
echo_server.c with similar results than on linux, with the  
tcp_nodelay set, and the results are again against cygwin binary.
On cygwin is too slow. I just don't know where the problem is.



On 2006/03/27, at 19:59, Steven Hartland wrote:

> ----- Original Message ----- From: "Dave Korn"
>
>> On 27 March 2006 16:39, Steven Hartland wrote:
>>> I've done quite a bit of digging and not found any real answers
>>> on why cygwin's scp performance is so poor.
>>  See the thread about "select() too slow" last week for an  
>> explanation of the
>> Nagle algorithm, how windoze's implementation of it appears to be  
>> crippling,
>> and how using TCP_NODELAY can fix everything.  (Thread ran from 11  
>> Mar to 19
>> Mar).
>
> As a quick and dirty hack I channed set_nodelay into set_nonblock  
> which
> seems to be set on all the sockets but unfortunately it doesn't  
> seem to help.
> Anyone more familiar with the internals of openssh know where this  
> might
> done?
>
>    Steve
>

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