XO Users, In short, I have bundled a set of 'hacks' which generally (and in my observation, dramatically) improve the user-perceived responsiveness of the Sugar UI. The hack bundle is available at http://dev.laptop.org/~erik/faster-hacks.zip
I write requesting independent evaluation of the costs and benefits of these modifications. To test you *must* be running our current official release: 8.2-767. -== Contents ==- There are several 'hacks' included in this bundle: 1) optionally disable frame appearance on activity switching, if the file /home/olpc/no-frame-on-tabbing exists 2) optionally disable autosaving on activity switching, if the file /home/olpc/no-auto-save exists 3) optionally start the X composite manager (xcompmgr) on sugar startup to prevent the redraw of activity windows when switching from one activity to the other (if /home/olpc/use-xcompmgr exists). 4) compcache, http://code.google.com/p/compcache/, which makes a compressed block device usable for swap out of a chunk of RAM. By compressing unused pages this system may offset memory usage increases incurred by using composite. -== Usage ==- To install and test on an XO, open the Terminal activity and run: wget http://dev.laptop.org/~erik/faster-hacks.zip unzip faster-hacks.zip cd faster-hacks sudo ./install-faster-hacks Restart Sugar, then, if you'd like to test with compcache, run: cd faster-hacks sudo ./start-compcache Note also that you can adjust the amount of RAM (in kilobytes) devoted to compcache by passing an argument to ./start-compcache, e.g.: sudo ./start-compcache 50000 By default it's set at 100000Kb (~100Mb). You can enable hacks 1-3 while running Sugar by executing: ./enable-faster-hacks and disable with: ./disable-faster-hacks Effects will be immediately apparent. The changes in Sugar source files and installed executable (xcompmgr) can be reverted and removed with: sudo ./uninstall-faster-hacks This step is a failsafe and likely unnecessary; ./disable-faster-hacks should be sufficient to stop the effects and the size of the installed programs is negligible (<30kb in xcompmgr). -== Discussion ==- Now continue to play with your XO as normal! Please report experiences and impressions. The 4 hacks are independent in operation and may be mixed and matched to achieve a variety of possible configurations. Keep in mind that these hacks present a tradeoff between existing features and UI responsiveness! The disabling of the frame removes a feature, but this feature (frame auto-appearance) may be unnecessary if we can rapidly switch between activities, as xcompmgr enables us to do. The disabling of autosaving removes a feature, but it drops the load on the processor which we incur when navigating between activities, thus improving switching performance. The use of xcompmgr represents a tradeoff between free RAM and system responsiveness. RAM is utilized to store offscreen framebuffers for each window in the X server. This obviates the need to have programs redraw themselves when they are switched into, dropping CPU usage during switching. But part of the RAM hit we incur by running xcompmgr may be offset by using compcache to provide a compressed swap partition-in-RAM. Comments more than welcome! Erik _______________________________________________ Sugar mailing list Sugar@lists.laptop.org http://lists.laptop.org/listinfo/sugar