RE: RT patch on Davinci PSP kernel
davinci-linux-open-source-boun...@linux.davincidsp.com wrote: > I was wondering if anyone has been able to apply a RT patch > to the kernel supplied by the DaVinci PSP. I'm working with > an OMAP L137 EVM board, and I need to run an application on > the ARM that handles some routines periodically. > > On the DSP I can make use of the timer to handle my RT needs, > but from the Linux part I have no idea how to do this. I've > tried applying the RT patch for the kernel version on which > the DaVinci kernel is based on, but even though I managed to > compile it, it crashes whenever I try to boot from it. > > Please let me know if anyone has managed to apply a RT > correctly or give me some advice on what direction to look > for to satisfy the needs of my application. What are the needs of your application? Do you really need the RT patches? Many features from RT are in the mainline now. You can of course do things preiodically under Linux without RT, it just depends on maximum acceptable latency... -- Jon Povey jon.po...@racelogic.co.uk Racelogic is a limited company registered in England. Registered number 2743719 . Registered Office Unit 10, Swan Business Centre, Osier Way, Buckingham, Bucks, MK18 1TB . The information contained in this electronic mail transmission is intended by Racelogic Ltd for the use of the named individual or entity to which it is directed and may contain information that is confidential or privileged. If you have received this electronic mail transmission in error, please delete it from your system without copying or forwarding it, and notify the sender of the error by reply email so that the sender's address records can be corrected. The views expressed by the sender of this communication do not necessarily represent those of Racelogic Ltd. Please note that Racelogic reserves the right to monitor e-mail communications passing through its network ___ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
Re: RT patch on Davinci PSP kernel
Hi Jon, Thanks for the quick answer, my application needs to handle a periodic routine every 16ms, with a latency of no more than 200us I've tried with the Linux timers and it work great when I had only that process running but when I added other processes depending on the CPU load the latency could sometimes be higher than the one accepted. This periodic routine will be handling the state machine for the application so it´s very important. What mainline routines would you recommend me using to try and handle this? Regards, -- Aquiles A. Lacruz López ___ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
RE: RT patch on Davinci PSP kernel
davinci-linux-open-source-boun...@linux.davincidsp.com wrote: > Thanks for the quick answer, my application needs to handle a > periodic routine every 16ms, with a latency of no more than > 200us I've tried with the Linux timers and it work great when > I had only that process running but when I added other > processes depending on the CPU load the latency could > sometimes be higher than the one accepted. That does sound like quite tight timing. Have you looked at SCHED_FIFO and priority? Maybe you can get away without PREEMPT_RT.. -- Jon Povey jon.po...@racelogic.co.uk Racelogic is a limited company registered in England. Registered number 2743719 . Registered Office Unit 10, Swan Business Centre, Osier Way, Buckingham, Bucks, MK18 1TB . The information contained in this electronic mail transmission is intended by Racelogic Ltd for the use of the named individual or entity to which it is directed and may contain information that is confidential or privileged. If you have received this electronic mail transmission in error, please delete it from your system without copying or forwarding it, and notify the sender of the error by reply email so that the sender's address records can be corrected. The views expressed by the sender of this communication do not necessarily represent those of Racelogic Ltd. Please note that Racelogic reserves the right to monitor e-mail communications passing through its network ___ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
Re: RT patch on Davinci PSP kernel
Jon you have helped me a lot! SCHED_FIFO did the trick... it works perfectly and I don't have to worry about the RT patch at least for the moment, Have a great weekend, -- Aquiles A. Lacruz López ___ Davinci-linux-open-source mailing list Davinci-linux-open-source@linux.davincidsp.com http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
