Zach Deedler wrote:
Hi Boris,
I've tried vertical sync on and off. Although, vsync on seems to be better,
I still get frame rate drops down to 4Hz for up to 10 seconds straight.
You MUST have vsync on for the paging timing prediction system to work at all. Paging
relies on the "unused" time slice that occurs between the "draw" thread finishing one
frame and starting the next frame when vsync says it is time. If vsync is off, there is no
wait period here, the draw threads starts a new frame as soon as it finishes the previous
frame, leaving no time for the pager to do work. If you have multiple CPUs, this is less
of a problem, but some of the work (DisplayList compile) must still be done on the thread
that runs the "draw" operation.
Drivers with poor VSYNC implementations (like the ATI ones until recently) can wreak
havoc with this, but you said you have an NVidia card.
It looks like any time hitching occurs, a node took over 600ms to load.
Since it seems to occur around the same areas in the database, I'm going to
investigate certain tiles causing the problems.
Good plan. If you can narrow it down to a repeatable problem tile, some progress might
be possible.
Q1) Does anybody know the advantages/disadvantages of using VBO, vertex
arrays, or display lists for drawables? Since vertex arrays seem to page in
faster, I am considering using them.
I can't confidently speak to this myself. My understanding is that different cards
perform differently for each of these. Old cards may not support VBO & VA, leaving you to
use DLs. DLs take more time to compile, but may be as fast at draw (or on some cards,
faster) compared to VBO/VA. Your mileage may vary, so test and choose.
>Thanks, I wish I could email you a beer.
Actually, if you figure out how to do so, send it to Farshid Lashkari. I already owe
him like a case or so, so we can just cut out the middleman.
--
Chris 'Xenon' Hanson aka Eric Hammil | http://www.3DNature.com/ eric at logrus
"I set the wheels in motion, turn up all the machines, activate the programs,
and run behind the scenes. I set the clouds in motion, turn up light and
sound,
activate the window, and watch the world go 'round." -Prime Mover, Rush.
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