Hi again, Still working on this one. When I rsync/ssh a big file to my server over the local network (100Mbit/s) with the --bwlimit=1000 I only have a small CPU load. SSH takes about 10% and rsync approximately 0-5%. In the end the transfer speed usually is around the value I set in bwlimit.
When I transfer the same file to a remote machine, where the bandwidth is limited to roughly 140KB/s and the bandwidth limit is set to something below this value I get around the same values which I have on the local network, SSH 10% and rsync somewhere between 0-5%. If I change the bwlimit value to 150KB/s or higher the SSH load goes up to 70% and rsync to 30% fully consuming my CPU. I think the problem is pretty clear now. Does anybody have an idea, what the next step could be to the resolution of this ? Regards, Jan -----Oorspronkelijk bericht----- Van: Jan Alphenaar [mailto:jan.alphen...@dotcolour.com] Verzonden: woensdag 17 februari 2010 12:27 Aan: 'cygwin@cygwin.com' Onderwerp: FW: Cygwin Rsync/SSH performance issue Hi At first this email was sent to the developers list, but I understood this list is more appropriate. Regards, Jan -----Oorspronkelijk bericht----- Van: Jan Alphenaar [mailto:jan.alphen...@dotcolour.com] Verzonden: woensdag 17 februari 2010 12:25 Aan: 'cygwin-develop...@cygwin.com' Onderwerp: RE: Cygwin Rsync/SSH performance issue Hi, In an attempt to narrow this down a bit I installed a RedHat machine with openssh-5.3p1 and rsync-3.0.7 (thus without cygwin) and did the same test as below. Transferring data, both up and downstream, are not giving me any CPU load. Although there is a small version difference in the rsync versions, I would conclude that this is somehow caused by the cygwin layer. If anybody can have a look at it, I would really appreciate it. If there is something I can do, please let me know. Warm regards, Jan -----Oorspronkelijk bericht----- Van: Jan Alphenaar [mailto:jan.alphen...@dotcolour.com] Verzonden: dinsdag 16 februari 2010 16:46 Aan: 'cygwin-develop...@cygwin.com' Onderwerp: RE: Cygwin Rsync/SSH performance issue Hi again, I did some more testing on this and figured out that rsync/ssh is only taking the full cpu if the bandwidth allocated to the session exceeds the true bandwidth available on the link. For example, if the uplink is 128KB/s and I pass in the --bwlimit=24 parameter the cpu is around 0%. Even --bw-limit=126 does not take 100% cpu, but --bwlimit=132 does. Would this be because of packet loss on the link and packets have to be retransmitted ? I will do a quick test tonight with rsync/ssh between two linux boxes, see what that gives me. Regards, Jan -----Oorspronkelijk bericht----- Van: Jan Alphenaar [mailto:jan.alphen...@dotcolour.com] Verzonden: dinsdag 16 februari 2010 11:34 Aan: 'cygwin-develop...@cygwin.com' Onderwerp: Cygwin Rsync/SSH performance issue Hi everybody, I am using rsync/ssh to copy files from my computer to my server and everything seems to function as expected, except performance. During a file transfer on my home computer (Intel I7) there is not a noticeable CPU load. But on other (older) machines the rsync/ssh transfer consumes all CPU resources on the sending side. I noticed there are other questions regarding this subject in the archives, but I could not find a solution for this. Also throttling the bandwidth to a lower value is not helping to reduce the CPU load. I am using quite a basic command to sync my files: rsync -e ssh * <user>@<server>:/data The versions of the software I am using are: Cygwin: 1.7.1-1 ssh: OpenSSH_5.3p1 rsync: 3.0.6 OS: WinXP Was anybody able to resolve this ? Any help is greatly appreciated. Warm regards, Jan -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
