Thanks for the information. I have less than 5% utilization on the server network port.
The switches are HP 4000M managed switches and show zero packet errors. Interestingly, utcapture shows packet loss only when they appear to be in compression mode and busy, eg a youtube video. During this time the latency will shoot from 2 to 12. The DTUs are the original series 1 or whatever they are called. I am starting to wonder if they get into compression mode, overwhelm the DTU cpu and start dropping packets, which in turn causes the DTU to conclude that it needs compression, starting a vicious cycle. Either way, it sure is strange. -----Original Message----- From: Joerg Barfurth Sent: 12/07/2009 07:06:53 Users mailing list Subject: Re: [SunRay-Users] FW: SRSS 4.2 + OSol 124/125/126 slower than SRSS 4.1? Marty Scholes schrieb: > After a few days of uptime, one or two of the heads on the triple > head displays started refreshing very quickly, and those ports on the > switches showed much higher, ~50%, link utilization. > > Sometimes the heads would revert to slow refreshes. I haven't > figured out the pattern of when they will behave a certain way. > > There appears to be two refresh modes: > 1. Low bandwidth refresh which is slow and updates blocks across the > screen top to bottom and left to right within each row, taking more > than a second. This makes scrolling in a browser/PDF/OO > Document/gnome-terminal/etc. a painful task. Yes. SRSS uses compression when the bandwidth it perceives to be available to the DTU is less than a certain threshold (iirc that threshold is ~8Mbps) > 2. High bandwidth refresh which is fast and consumes the ethernet > link, smoothly refreshing the whole screen in less than half a > second. > Above the mentioned threshold the server does not use compression. I wonder why that is so much faster? What kind of DTUs do you have? > I seem to recall that 4.1 ran in "high bandwidth" mode quite often > but 4.2 prefers the slower mode. Changing the DTU to the 4.1 > firmware had no effect, so I can only assume it is SRSS which is > making these decisions. > It is. I don't know that anything changed there. (But can't rule it out either.) > Assuming (naive, I know) that this is how SRSS operates, is there a > way to coax it into the "high bandwidth" mode permanently? > Provide the needed bandwidth :-o I have no idea what your network or server does to make SRSS perceive much less available bandwidth than there really is. You can force compression to on directly or by setting a bandwidth limit below the threshold, but that appears to be the exact opposite of what you want. The best you probably can do in the other direction is to force a lossless compression mode - but there will still be some compression. You can change all mentioned settings using the popup UI of 'GUI' firmware (under 'Advanced') or using .parms files (see the utfwadm(1M) man page). You could also check using utquery(1M) whether you inadvertently have any of these settings on. HTH - Jörg _______________________________________________ SunRay-Users mailing list [email protected] http://www.filibeto.org/mailman/listinfo/sunray-users
