Hi Denis, ... On Thu, Jan 03, 2008 at 03:11:59AM +0100, Denis Oliver Kropp wrote: > Alexandre Franke wrote: > > Hi, > > > > We are using STi7109 from ST Microelectronics with the STAPI M6 DirectFB > > driver. > > According to their documentation, the 2d blitter should be able to blit at > > 200MPixels/sec. We enable hardware acceleration and have some performance > > issue. > > We have a small test program that shows the time taken by several functions > > and > > it appears that Blit is particularly slow, taking a bit more than 3 seconds > > for > > a 2MPixels image (1920*1080), which is roughly 300 times slower than > > expected. > > We also tried with hardware acceleration disabled and it takes nearly half > > the > > time it takes with acceleration enabled (alright, it is faster without > > hardware acceleration than with it). > > Blending seems to cause software fallbacks on the system. You can verify that > by using the "no-software" option, if your DirectFB version is recent enough.
Ok, we will test that tomorrow. What seems strange to me is that no-hardware is faster than with hardware accell. > If you use hardware acceleration on a surface it is stored in video memory and > subsequent software fallbacks will read from video memory. If you disable all > acceleration, surfaces stay in system memory and you will get better blend > performance. Ok. > It would be good the check the hardware capabilities and optimize the > application. well, the part that the directfb accell supports. The hardware is capable of doing 3 source blits, at least the documentation says so. > When do you need blending of the whole frame? We don't really need blending, we just need to write the background buffer to the main layer (since our fbdev doesn't support additional layers, altough i am unsure how directfb works in this regard, and thus my previous rather clueless questions about directfb support of hardware layers), and if it could be an opaque blit, it would be just as gine. Thanks for your feedback. Friendly, Sven Luther _______________________________________________ directfb-users mailing list [email protected] http://mail.directfb.org/cgi-bin/mailman/listinfo/directfb-users
