Hi all, > -----Original Message----- > From: geda-user-boun...@moria.seul.org > [mailto:geda-user-boun...@moria.seul.org] On Behalf Of Richard Barlow > Sent: Friday, November 12, 2010 3:00 PM > To: gEDA user mailing list > Subject: Re: gEDA-user: PCB+GL notes on VBOs > > Hi, > > On Fri, 2010-11-05 at 09:46 +0000, Peter Clifton wrote: > > 1. My VBOs and arrays are pretty large buffers, to fit lots > of geometry. > ... > > So.. we have a large buffer. That is a large chunk of > graphics memory > > to be requesting all the time. I think that contributes if the card > > doesn't have a decent chunk free yet. > > I did a little bit of investigation and I suspect this is the > culprit to everyone's poor performance. > > I ran the power-hw board on my machine and achieved around 85FPS. > Felipe ran the same board on his machine and achieved around 18FPS. > > My graphics card has 1GB of VRAM, Felipe's has 256MB (I > couldn't easily compare this to other people's results as not > many people said what card/driver they were using). I have > tried quadrupling the size of the VBO and now get around > 17FPS, which is considerably less than a quarter of my > previous result and almost exactly the same as what Felipe got. > > I would say that this indicates that the large size of the > buffer is to blame for the speed problems if everyone else > has cards with ~256MB of VRAM and therefore the driver is > having to swap out part of the buffer into system memory. > > > NB: I ran the above test with the larger buffer on code > before commit 0fa243b4bf which seems to change how the buffer > allocation is performed. > I have tried running it with the quadrupled buffer on the > head of that branch and see no drop in performance any more. > I still think my analysis stands though if people don't have > enough VRAM to hold the size of the buffer used by the > power-hw board. > > Richard >
FWIW, a large amount of graphics memory is one thing, my 256 Mb graphics memory is shared memory which is contributing to the total performance equation. I still have to start the prcess of fine tuning modelines and BIOS to get the max performance wrung out of the HW. Kind regards, Bert Timmerman. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user