On 12/22/2009 11:07 PM, Dave Airlie wrote: > On Wed, Dec 23, 2009 at 6:57 AM, Izik Eidus<iei...@redhat.com> wrote: > >> On Wed, 23 Dec 2009 06:29:30 +1000 >> Dave Airlie<airl...@gmail.com> wrote: >> >> >>> On Tue, Dec 22, 2009 at 10:00 PM, Yaniv Kamay<yka...@redhat.com> >>> wrote: >>> >>>> Hi, >>>> >>>> All QXL structures are defined as packed see qxl_dev.h. >>>> >>>> >>> This will prove interesting in the future I expect, unaligned accesses >>> are really >>> really slow on certain hw platforms, this is fine when you are >>> designing for x86 only, >>> but for non-x86 hw there is a chance that the unaligned access will >>> kill performance. >>> >> >> Currently we can not change qxl structures due to competability issues. >> We also need to take into considiration the ratio bettwn the structures >> and the bitmap data which is much more segnificant. any how we will take >> this into consedoration at the time we'll have to break competability. >> >> Another issue is that currently we have no experience with spice >> support for other archs, It will be better to try fix this issues at >> the moment we will start to see ports to other archs... >> >> > http://lwn.net/Articles/259732/ > > is probably worth reading, > > http://msdn.microsoft.com/en-us/library/aa290049%28VS.71%29.aspx > > for the Windows folks, > > I've also read that even on x86 unaligned accesses can slow things down, > so I'd suggest fixing these even there. at least for future QXL interfaces > it would help to make sure they work unpacked and are portable. > > Dave. >
On some platforms (Sparc IIRC) you don't have to worry about the performance impact. It'll cause a bus error. Y. > ------------------------------------------------------------------------------ > This SF.Net email is sponsored by the Verizon Developer Community > Take advantage of Verizon's best-in-class app development support > A streamlined, 14 day to market process makes app distribution fast and easy > Join now and get one step closer to millions of Verizon customers > http://p.sf.net/sfu/verizon-dev2dev > _______________________________________________ > Spice-space-devel mailing list > Spice-space-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/spice-space-devel > ------------------------------------------------------------------------------ This SF.Net email is sponsored by the Verizon Developer Community Take advantage of Verizon's best-in-class app development support A streamlined, 14 day to market process makes app distribution fast and easy Join now and get one step closer to millions of Verizon customers http://p.sf.net/sfu/verizon-dev2dev _______________________________________________ Spice-space-devel mailing list Spice-space-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/spice-space-devel
