Angus Dorbie (dorbie++at++sgi.com)
Mon, 18 Oct 1999 13:09:54 -0700
Performer tries to make a very accurate estimation of download times for
your platform based on measured strided subteximage results stored in a
table. It uses that table to predict the cumulative time issued
downloads will take. It doesn't block & time because that would be slow.
In one other case we saw excursions of up to 9ms. After investigation it
transpired the problem lay in download times exceeding DTR estimate.
We're still investigating. I'll be spending a lot of time on this next
week (I have other priorities this week). I'll keep you updated.
Cheers,Angus.
"Paik, Charles C" wrote:
>
> Hi,
>
> 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 630166-0516
>
> email: charles.c.paik++at++boeing.com
> phone: 314-233-6807 fax: 314-232-4181
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-- "Success is the ability to go from one failure to another with no loss of enthusiasm." - Winston Churchill.Performer + OpenGL examples and tutors: http://www.dorbie.com/
This archive was generated by hypermail 2.0b2 on Mon Oct 18 1999 - 13:10:00 PDT