> -----Original Message----- > From: Harish Pillay [mailto:[email protected]] > Sent: Thursday, April 22, 2010 5:25 PM > To: ZHOU,JON (A-Singapore,ex1) > Cc: [email protected] > Subject: Re: [Slugnet] was the real-time patch merged kernel main stream? > > Jon - > > Hi. Have you checked https://rt.wiki.kernel.org/? > >> I remember on several years ago, both montavista and windriver provided >> the >> real-time patch(hard-realtime ? ) >> nowadays, these paths has been merged with the kernel mainstream ? >> what's the situation of kernel regarding the real-time features? >> is it soft-realtime or hard-realtime? >> ps:from kernel 2.6 preempt kernel was introduced, but I don't think it is >> a >> true real-time (even it is not soft-time?) > > A lot of the work is still ongoing and some vendors like Red Hat have > a RT kernel for customers who need it. Not sure right now if the kernel > is hard-realtime.
RT changes have _slowly_ been merged upstream. This has been going on as far back as I can remember, and I've been using the patch since 2006 and packaging realtime kernels since 2007. It is indeed safe to say that most realtime functionality (the scheduling and preemption code) have enough of a footprint now (2.4 series has RTAI), but for stuff like embedded work a patch _is_ necessary for a number of other contributing factors. After all, the idea of hard preemption is totally anti-scheduler. Most of what you get from the kernel is soft realtime, or a very close hard realtime for robotics and lasers (a few milliseconds +- will not be harmful). For industrial applications where the deadline is microsecond-sensitive and any fluctuation must be avoided, I doubt Linux is a solution. For eg. a rocket launchpad console will not be running Linux RT. So this really depends on the hardness of the hard realtime you're refering to, i.e what and where your application of realtime is. -- GPG/PGP ID: B42DDCAD _______________________________________________ LUGS Mailing list - [email protected] List FAQ: http://wiki.lugs.org.sg/LugsMailingListFaq Info page: http://www.lugs.org.sg/mailman/listinfo/slugnet To unsubscribe send an empty email to: [email protected]
