Re: UDP jitter

["Nebojša Ćosić" <nebojsa@asnn.org>]

Дана Fri, 8 Nov 2013 14:35:44 +0100 (CET)
Thomas Gleixner <tglx@linutronix.de> написа:

> On Fri, 8 Nov 2013, eg Engleder Gerhard wrote:
> >  > -----Ursprüngliche Nachricht-----
> > > Von: Thomas Gleixner [mailto:tglx@linutronix.de] 
> > > Gesendet: Freitag, 08. November 2013 12:31
> > > An: Stanislav Meduna
> > > Cc: Nebojša Ćosić; eg Engleder Gerhard; linux-rt-users
> > > Betreff: Re: UDP jitter
> > > 
> > > There are other ways to solve this without touching a single 
> > > line of kernel code. The technology is all there, you just 
> > > have to use it. Of course that requires to understand it in 
> > > the first place, though this seems to be way harder than 
> > > spending a lot of time tracing the problem and then yelling 
> > > "priority inversion" and hope that the RT folks are going to "fix" it.
> > 
> > Can you give us a hint which technology to use? Currently I am
> > trying to use QoS Multi Band Priority Queueing.
> 
> Well, it really depends on your requirements. Assuming you have a
> simple binary decision (Bulk and VIP traffic) a simple 2 band priority
> queue should work.
And how exactly is it going to help? You still have fifo, and you still
get messages from higher priority thread stuck waiting for low priority
task to finish sending whatever it has in there (please note how I
avoid mentioning priority inversion here).
By the way, by default you have pfifo_fast in there, which is capable
enough to do the priority based queuing.

> 
> Thanks,
> 
> 	tglx

Excuse my ignorance
Nebojša
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