-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 12/4/2012 4:41 AM, Michael Haberler wrote: > A key element for an RT kernel of any kind is high-resolution > timer support being in place in the kernel for results to make any > sense. That can be assumed granted on PC/x86, but it cannot with > the average ARM board. There will be _some_ timer support, but not > necessarily a hires one. > > It is likely in place if somebody ported Xenomai to that board to > start with, because that's clearly the more popular option in this > league. And it might still mean the RT_PREEMPT kernel needs those > patches carried over from whatever source manually. > > That, of course, makes the 'easier build' assumption moot, it can > very well be harder, which raises the question why do it in the > first place if one can have better latency with Xenomai to start > with with less work. > > So much for the value of re-applying past experiences;)
It gets worse. The PREEMPT-RT code relies on SMP clean kernel code in order to work properly. The x86 world and the Linux kernel in general went through many pains and discovered *LOTS* of obscure bugs when PREEMPT-RT began getting integrated into the kernel. That means the vendor written driver for <obscure device> on your ARM board needs to be a clean SMP capable driver, not some hack that relies on there never being more than one CPU in the system. And since a *LOT* of these ARM boards only have one processor, you can guess how often that happens. :) - -- Charles Steinkuehler [email protected] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.11 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAlC91vQACgkQLywbqEHdNFylSgCfRp/I2uvNROhYBwfVUT5mXCI9 LhwAoNEJ3oJvsd4DVKfIx7HWvyz4kQa8 =kJLk -----END PGP SIGNATURE----- ------------------------------------------------------------------------------ LogMeIn Rescue: Anywhere, Anytime Remote support for IT. Free Trial Remotely access PCs and mobile devices and provide instant support Improve your efficiency, and focus on delivering more value-add services Discover what IT Professionals Know. Rescue delivers http://p.sf.net/sfu/logmein_12329d2d _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
