On Fri, 2011-09-16 at 23:17 +0200, Mike Gabriel wrote: > Hi John, hi Alex, > > On Fr 16 Sep 2011 21:56:38 CEST "John A. Sullivan III" wrote: > > > Hello, all. Since moving to the newer clients using libssh, I've > > noticed what appears to be a performance degradation. It smells like > > Nagle coalescing packets, e.g., most of the screen will paint, then it > > will pause a moment, and then the rest will paint. Is there any chance > > we have neglected to disable Nagle when invoking libssh? > > > > This appears to have affected the SNMP over SSH project: > > http://books.google.com/books?id=S62is2vVoVgC&pg=PA29&lpg=PA29&dq=libssh > > +nagle&source=bl&ots=F8Iw-pvQxd&sig=f5dfy0K0ewzSZOhqzTJRSKsDKZ8&hl=en&ei=KppzTrCZD4LJgQeMxLzzDA&sa=X&oi=book_result&ct=result&resnum=1&sqi=2&ved=0CBwQ6AEwAA#v=onepage&q=libssh%20nagle&f=false > > > > This is in section 4.1. The difference was a latency of over 800ms to > > one of under 60ms. That seems to be about what I am seeing. There is a > > delay of roughly a second and then the rest of the screen comes through. > > Thanks - John > > Indeed the TCP_NODELAY (which means: turn Nagle off) is not set for > the ssh tunnel in X2goClient. It probably is for the SSH connection > itself, as the SNMP patch has been reported to libssh upstream and > their patch suggestion has been sensible. However, for the SSH tunnels > built up for X2go this TCP_NODELAY option does perhaps not get set. > > @Alex: would this patch fix that in x2goclient??? > > diff --git a/sshprocess.cpp b/sshprocess.cpp > index 9e72e8f..03ee9b6 100644 > --- a/sshprocess.cpp > +++ b/sshprocess.cpp > @@ -88,6 +88,7 @@ void SshProcess::tunnelLoop() > const char y=1; > #endif > setsockopt(serverSocket, SOL_SOCKET, SO_REUSEADDR,&y, sizeof(int)); > + setsockopt(serverSocket, IPPROTO_TCP, TCP_NODELAY,&y, sizeof(int)); > > address.sin_family=AF_INET; > address.sin_addr.s_addr=INADDR_ANY; > > > @John: could you get the latest sources of x2goclient from our Git: > > git clone git://code.x2go.org/x2goclient.git > > and run debuild -uc -us (plus fullfill build-deps before) on a Debian > squeeze or above system and check if the patch fixes your delays??? > > Best+Thanks, > Mike <snip> Thanks for digging that out, Mike. I'm going to mark this mail so I don't forget it as I likely won't have a chance to do this before Monday. Perhaps we'll have confirmation from Alex by then - John
_______________________________________________ X2go-Dev mailing list [email protected] https://lists.berlios.de/mailman/listinfo/x2go-dev
