Chris, Modern VNC Viewers have an option to rate-limit pointer events, which is really aimed at avoiding hosing very slow networks. However, the underlying PointerEventInterval can be set via the Expert tab (or in the registry), to ten or twenty milliseconds, to provide the level of rate-limiting you're looking for.
We deliberately don't rate-limit pointer events by default, so as to interfere as little as possible with the end-to-end behaviour - it's not a bug as such. :) Cheers, -- Wez @ RealVNC Ltd > -----Original Message---- > From: vnc-list-boun...@realvnc.com [mailto:vnc-list- > boun...@realvnc.com] On Behalf Of Christopher Woods > Sent: 07 September 2009 21:59 > To: vnc-list@realvnc.com > Subject: Mouse cursor polling rate causing massive lag on remote > device... Possible bug? [with details] > > Hi list, > > Searched elsewhere but couldn't find any relevant discussions. I may > have > stumbled upon a bug... > > I've noticed that I can consistently reproduce a scenario whereby > MASSIVE > lag is induced in the remote device as soon as the mouse cursor is > moved > rapidly or any window is dragged / any motion involving the mouse is > involved. The fault seems to be the VNC client on the controlling > machine > not adequately throttling mouse events, thereby overloading the remote > device. 100% CPU usage is observed on the remote device and the display > and > actions on the device are noticeably slowed down almost to a crawl. > > Both devices are connected via GigE through a Netgear ProSafe switch > and > short runs of ethernet cable, and both are running XP SP3 with an > identical > antivirus/malware/firewall config (Kaspersky 2009). I tried all sorts; > in > the end rate limiting the mouse events in the VNC client worked as a > temporary measure, but I did not feel this was a sufficient solution. > > What's causing it is an unusual but predictable culprit: my Razer > DeathAdder > mouse. It's a gaming mouse, and therefore has the potential to reach > ridiculous polling rates and DPIs. By default, I use it in its 1,000Hz > polling rate mode (I FPS game in my spare time and 1,000Hz is its > default > setting - because you *know* those extra few nanoseconds make all the > difference between a torso and headshot! ;) The polling rate is > switchable > between 125Hz, 500Hz and 1,000Hz via the DeathAdder control panel which > loads as a system tray applet; in 500Hz mode, there is occasional lag > when > extreme/violent actions, but in 125Hz mode the behaviour of the remote > device is exactly as you'd expect... It works perfectly. I can grab a > window, drag it around and violently shake it to all extremes of the > display > - and the remote device updates perfectly, just as you'd expect, with > the > expected higher - but not maxed out - CPU usage. > > When I reverse the setup, and remote control machine A with machine B, > mouse > inputs and local/remote refresh work exactly as expected, but that is > not > unusual as the other machine is a laptop (so only has a trackpad > polling at > the standard 100Hz). Other SMB / FTP transactions, pings etc all work > at the > expected throughput rate for a gigabit ethernet connection, so there is > no > issue with rate negotiation by the devices' NICs. > > It's an unusual set of circumstances that are prompting this bug into > existence, but I can't be the only person out there with a quick- > polling > mouse who's observed this problem. Have I uncovered a hitherto unknown > bug, > or has this already been acknowledged as something for the RealVNC devs > to > fix for a future release? > > Cheers > Chris > > > _______________________________________________ > VNC-List mailing list > VNC-List@realvnc.com > To remove yourself from the list visit: > http://www.realvnc.com/mailman/listinfo/vnc-list _______________________________________________ VNC-List mailing list VNC-List@realvnc.com To remove yourself from the list visit: http://www.realvnc.com/mailman/listinfo/vnc-list
