Paik, Charles C (Charles.Paik++at++MW.Boeing.com)
Mon, 18 Oct 1999 14:57:02 -0500
I'm having a performance glitch when using a cliptextures. My application is
a flight sim application that pages in tiles and cliptexture as I fly along.
The tiles are extremely regular with no high or low dense areas. It is in
APP_CULL_DRAW mode, with culls and draws on their own processors. I have
set high priorities to the draw processors. All processes (APP, DRAW, CULL,
DBASE, ISECT) are on separate restricted processors. I set the cliptexture
paging maximum time to 3 ms.
I have a separate program that graphs the real-time performance. App & Cull
are good, but draw looks likes a big slow-rolling wave and lots of little
sharp waves. I am sure that the big waves are the database tiles, and the
little waves are the cliptexture paging. I update the cliptexture center
every frame. Every few seconds (1 to 10 seconds), there is a sharp spike
that is about 5 to 20 ms large. I am sure this is not a graphing error
because I also see frame drops are visibly seen in the application. This
spike has irregular frequency and size, even when I fly a canned flight
path.
When I turn the cliptexture paging maximum time to 0 ms (I just don't update
the cliptexture center), the little waves go away and I am left with a big
slow-rolling wave, and there are no large sharp spikes. None. It's rock
solid. This makes me think that my problem is probably due to cliptexture
updating. I don't think it's a background job because there are no spikes
when I take away the cliptexture paging time. Can anyone help me figure
this one out?
I updated IRIX and Performer 2 weeks ago. So, I think I'm up to date with
version. I run on an Onyx with IR2 graphics on 7 pipes.
Thanks in advance.
-- Charles C. Paik The Boeing Company P.O. Box 516 MC S106-4715 St. Louis, MO 630166-0516email: charles.c.paik++at++boeing.com phone: 314-233-6807 fax: 314-232-4181
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