Dear Philippe, in message <[EMAIL PROTECTED]> you wrote: > > Open question: to your opinion, is 2.6 on low-end embedded hw doomed "by > design"
Something like that. > and why, or do you think that part of the reluctance to move to 2.6 is mostly > explained because 2.4 is just fine and up to the task, IOW it's kind of a > "don't > fix if it ain't broken" perception? Please see http://www.denx.de/twiki/bin/view/Know/Linux24vs26 and http://www.denx.de/twiki/bin/view/Know/Clock100vs1000Hz The major causes of the serious performance degradation under 2.6 are (1) the increased code size (especially the code that is running in interrupt context and for test switching - check for example just the code size of the scheduler and compar ewith it's size under 2.4), and (2) the increased clock frequency. OK, (2) has been partially fixed in the mean time by making the clock frequency adjustable, so you can go back to the old value of 100 Hz on low end systems. The other factor remains. And yes, this is "by design" - Linux is more and more designed for high end machines like fat servers running thousands of tasks or other multiprocessor systems with N GHz clocks. A MPC860 at 50 Mhz is just another world. <joke> I see a business opportunity to revive the 2.2 or even the 2.0 kernel tree development especially for small systems wth real-time requirements. </joke> Best regards, Wolfgang Denk -- Software Engineering: Embedded and Realtime Systems, Embedded Linux Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: [EMAIL PROTECTED] If there was anything that depressed him more than his own cynicism, it was that quite often it still wasn't as cynical as real life. - Terry Pratchett, _Guards! Guards!_
