Go Back   nV News Forums > Linux Support Forums > NVIDIA Linux

Newegg Daily Deals

Reply
 
Thread Tools
Old 01-29-09, 10:13 AM   #1
motd2k
Registered User
 
Join Date: Jan 2009
Posts: 27
Default VdpVideoSurfaceGetBitsYCbCr speed

I realise that by its entire nature VdpVideoSurfaceGetBitsYCbCr is going to be pretty slow, but are there any hints on maximising it's performance?

It's pegging a single core of my AMD 5000+ trying to call this on a 1080p24 video - does that sound about right?
motd2k is offline   Reply With Quote
Old 01-29-09, 11:11 AM   #2
Stephen Warren
Moderator
 
Stephen Warren's Avatar
 
Join Date: Aug 2005
Posts: 1,327
Default Re: VdpVideoSurfaceGetBitsYCbCr speed

Are you actually experiencing bad performance using this API (i.e. it takes an unexpectedly long time to operate), or just that the CPU usage is high?

The download process has to do the following:

a) Wait for the GPU to complete any previous rendering commands to the surface that you're downloading (which may include decoding video), since VDPAU functions mostly just send commands to the GPU and don't wait for them.

b) Actually perform the download of the data

Hence, overall execution time can include the time taken for the GPU to execute other operations besides the download.

Also, the wait-for-everything-to-download code on the CPU probably busy waits for at least some of the time, so just because CPU usage is high doesn't mean that the CPU is working hard, just doing nothing waiting for the GPU to finish.

I'm not sure right now if the busy wait implementation could be improved so as to not use CPU. I'll keep it in the back of my mind to look at this.
Stephen Warren is offline   Reply With Quote
Reply


Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


Similar Threads
Thread Thread Starter Forum Replies Last Post
Need for Speed: Most Wanted returns with open-world urban racing News Latest Tech And Game Headlines 0 06-04-12 07:30 PM
German ISP claims to deliver 4.7Gbps download speed in field test News Latest Tech And Game Headlines 0 06-01-12 05:50 AM
9800 GTX and Fan Speed Control HarryMan NVIDIA Linux 0 05-25-12 11:50 PM
in 307.11 don't read Fan speed with nvidia-settings sl1pkn07 NVIDIA Linux 2 05-21-12 10:08 AM
Gainward GeForce4 Ti 4200 and overclocked AGP Prefect47 NVIDIA GeForce 7, 8, And 9 Series 6 09-16-02 03:50 PM

All times are GMT -5. The time now is 06:16 AM.


Powered by vBulletin® Version 3.7.1
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Copyright 1998 - 2014, nV News.