Hi Michel, On 29 Aug, this message from Michel Dänzer echoed through cyberspace: >> > > > Although I found no evidence documented evicende of this, I suppose >> > > > this is because XFree (plain), although implementing Xvideo, doesn't >> > > > use the hardware acceleration in the ATI chips, whereas the GATOS >> > > > drivers do just that. >> > > >> > > Not quite. Plain XFree86 uses the frontend scaler, which also does the >> > > colorspace conversion. The reason for the CPU load is that the data is >> > > transferred to the card with regular memcpy. If the GATOS drivers use >> > > (virtually) no CPU for the transfer, that hints at that they use bus >> > > mastering for the transfer. Very interesting, I'll have to look at the >> > > code. >> > >> > False alarm, they also use memcpy. In fact, the code looks very similar to >> > plain XFree86, so I'd be surprised if it makes any difference. >> >> Did you look at the r128 driver only? My test showing the decrease in CPU >> load was on a Rage Mobility-equipped Dell laptop (i.e Mach64-compatible >> using the ati driver). > > Nope, I looked at the mach64 code as well. Looks like slightly modified r128 > code. The only real difference seems to be that GATOS supports additional > video chips, but that doesn't apply to us.
Hmmm..... strange, then. I tried the GATOS drivers on my TiBook (with Josh's fix -- thanks), but they give the same performance as the standard one, plus a (probably) endianess bug: they seem to 'reverse' successive image blocks on screen; probably 4- or 8-pixel-wide blocks... To sum up my performance comparisons so far, all with XFree 4.1.0 from unstable, and vlc 0.2.83: - Mach64/i386 without GATOS: no Xvideo (driver is broken); vlc uses 45% + 16% cpu (two 'consuming' threads); X uses 25% cpu. - Mach64/i386 with GATOS driver: Xvideo works, vlc uses 25% (other threads insignificant), X uses between 2% and 5% - Voodoo3/i386: Xvideo works, X around 25% and vlc around 30% (roughly) - Rage128/ppc: Xvideo works, X between 10% and 20%, rest consumed by vlc. The Mach64 is on a Dell laptop w/ Celeron 600, the Voodoo is a PIII/666 desktop, and the ppc is my TiBook/400. So the question is: why does X on the Dell use so little CPU, and why can't we achieve the same thing on ppc (the Voodoo was for comparison only)? Michel ------------------------------------------------------------------------- Michel Lanners | " Read Philosophy. Study Art. 23, Rue Paul Henkes | Ask Questions. Make Mistakes. L-1710 Luxembourg | email [EMAIL PROTECTED] | http://www.cpu.lu/~mlan | Learn Always. "
