Thanks, Dan. This is to add VoIP to a gateway box that spends a lot of time in the kernel doing network processing... even with realtime scheduling, i'm afraid that preemption by the kernel may result in unwanted latency. I would think that this might also be of interest to someone who is dividing the work between two processors... but i guess it is not an issue most people would face. -Ted > > Putting pjmedia in kernel space in order to increase performance is the > wrong way to go IMHO. If the performance and latency isn't what you require > there are other ways to handle it than porting pjmedia to a kernel module. > First of all read: > http://trac.pjsip.org/repos/wiki/FAQ#Performance, and then read: > http://trac.pjsip.org/repos/wiki/FAQ#media. > > If you're still having problems with performance there are(at least) two > ways that has saved my day a couple of times: > > 1. Optimize the source code yourself. Coding the re-sample filter in > in-line assembler can do wonders with the performance ;-) > > 2. When the sound device port is used as a clock source it is important > that the thread handling the audio is interrupted as little as possible. To > do this you may write you own audio back end that handles the sound in a > thread with a high scheduling priority and a real-time scheduling > policy(SCHED_RR or SCHED_FIFO). Note that the application needs to have > superuser privileges in order to set the schedule policy to SCHED_RR or > SCHED_FIFO. > > Regards, > Dan > > Ted Merrill wrote: > > Does anyone have opinions on whether putting putting pjmedia > > into the linux kernel (with the remainder of pj stack in user > > space for safety) would significantly reduce latency on a busy > > system? The theory is that, in addition to avoiding round trips to > > user space, the code in the kernel could be made to run at > > signicantly higher priority than would be possible in user space > > (aided by some suitable locking). > > > > Although the entire pj stack seems to have been ported to linux > > kernel, there is no code provided to run pjmedia in a different > > process (or processor!) than the upper part of the stack... > > some sort of system of messages would need to be used to "remotely" > > connect pjmedia with the upper stack. > > Has anyone thought about issues involved with this? > > > > Has anyone recently run the entire pj stack in the linux kernel? > > recently run parts of it? Is it still working? > > > > Thanks > > Ted Merrill > > > > _______________________________________________ > > Visit our blog: http://blog.pjsip.org > > > > pjsip mailing list > > pjsip at lists.pjsip.org > > http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org > > _______________________________________________ > Visit our blog: http://blog.pjsip.org > > pjsip mailing list > pjsip at lists.pjsip.org > http://lists.pjsip.org/mailman/listinfo/pjsip_lists.pjsip.org
