On Mar 28 19:43, Steven Hartland wrote: > From: "Corinna Vinschen" > >- The worst of all is ssh itself. When reading blocks from the network, > > it uses an 8K buffer. Whatever you try with setting different socket > > buffer sizes or disabling the Nagle algorithm, nothing has any > > interesting impact if not ssh's own buffer is raised in size. By just > > setting the buffer to 64K (in the ssh source file clientloop.c, > > function client_process_net_input, line 575), the above copy started on > > Cygwin suddenly races along with 4.2MB/s. > > I just tried the same thing here and get: > >From FreeBSD to Cygwin, started on Cygwin: 8.7MB/s up from > 6.4MB/s unpatched. > > Thats a good improvement, unfortunately it has no bearing on the key > test here which is: > >From Cygwin to FreeBSD, started on FreeBSD which is still 731KB/s
Well, this will be some other buffer, this time in sshd. > >- The default WinSock send/recv buffer size is apparently 8K. This is a > > quite small buffer for bulk data transfer. Raising this buffer to 64K > > (setsockopt's SOL_SOCKET/SO_RCVBUF option), too, results in a > > throughput of 5.9MB/s. > > > > Note that the performance suffers again, if the socket buffer is > > smaller than the application buffer. > > I'd be interested in trying this, where abouts did you set this in > the ssh code? I've set it in Cygwin since I know the code better. In ssh, you'd do it after calling socket() and before calling connect() resp. bind(). > >- Disabling the Nagle algorithm (setsockopt's IPPROTO_TCP/TCP_NODELAY > > option) doesn't really have a lot of impact, but it's slightly > > noticable. The throughput goes up to 6.1MB/s. > > Again could you tell me where you set this? For testing, in ssh_session2_setup in ssh.c. You could just set it where you set the buffer size, though. If you need a good example, use the HPN patch. > ================================================ > This e.mail is private and confidential between [bla]. Sigh. Corinna -- Corinna Vinschen Please, send mails regarding Cygwin to Cygwin Project Co-Leader cygwin AT cygwin DOT com Red Hat -- Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple Problem reports: http://cygwin.com/problems.html Documentation: http://cygwin.com/docs.html FAQ: http://cygwin.com/faq/