Until XXXX is so there cant be YY, this is a fact, that is not a fact, that is a statement.
If you have numbers or such to base your STATEMENTS on , please do so, but don't present your opinion as a fact. Also lala-land and similar name calling doesn't add to your credibility. Hard realtime is as you state not fast or slow, but in a deterministic time frame, total agreement there. Perhaps you should have a look at the preempt-Rt patches since you don't seem knowledgeable about things like the 'threaded interrupt handler' and such, On a MP machine preempt-RT actually outperforms most other RT systems :-D ... So I think perhaps you should speak a bit softly since there is a lot of people working on making preempt-rt exactly that, a general hard realtime system, and some of them are rather acomplished. If you think a lot of smart people are stupid, then the odds are not in the favour of your opinion ..... / regards, Lars Segerlund. 2012/4/24 Mark Hounschell <dma...@cfl.rr.com>: > On 04/24/2012 05:08 AM, Lars Segerlund wrote: >> >> This is not based on facts, rt-preempt does provide hard realtime and >> strive to provide hard realtime, where have you come up with the >> notion that it does not ? >> >> Please, don't spread misinformation, this is pure FUD ....... >> >> Check osadl.org and their test rack, it will perhaps shed some light >> on the quality assurance they try to do. >> It is hard to argue with numbers, also check a recent kernel and a >> 'good' system. >> Some system have latency problems, but most are fine, atleast a >> worstcase of 50 usor so under hard load and normal times in the low 10 >> to 20 us range. >> > > Your in lala land. The Linux kernel, even with the RT patch has so much "per > CPU" crap in it, there is no way to prevent it from steeling usecs from your > application. The per CPU timer interrupt alone takes a few usecs away from > your application every HZ. A hard RT env is one in which you can always, > every time, do a predefined work in the same amount of time. Fast or slow > isn't the key. It's determinism. The timer interrupt alone prevents that. > And it's not the only thing. I've got 8 cpus on my machine but the kernel > has to have a piece of every one of them. Until there is isolation from the > kernel, there cannot be "Hard RT". This is fact. > > Mark ------------------------------------------------------------------------------ Live Security Virtual Conference Exclusive live event will cover all the ways today's security and threat landscape has changed and how IT managers can respond. Discussions will include endpoint security, mobile security and the latest in malware threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/ _______________________________________________ Emc-developers mailing list Emc-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-developers
