[Jackit-devel] [linux-audio-user] pam modules / non root users can't get realtime privileges.

[Jack O'Quin]

On 2/4/07, Ken Restivo <ken at restivo.org> wrote:
> On Sun, Feb 04, 2007 at 04:54:01PM -0800, Fernando Lopez-Lezcano wrote:

> > It looks like the package was built to use capabilities. I don't know
> > what jackd does when it does not find the proper capabilities (which
> > will not be found if you are using pam), whether it still tries to get
> > SCHED_FIFO or if it just gives up, it looks like the later.

I think we handle that correctly, i.e. go ahead and try to set SCHED_FIFO
anyway and use it if available.

The current JACK engine implementation fails if -R is selected and
realtime scheduling is not available.  That changed fairly recently,
IIRC, so an older version might continue running in that case.

> What the....  I certainly hope not.
>
> I thought that was a spurious error message to be disregarded, since jackd definitely *is* running with RT priorities, at least on my machine, it reports:
>
> FreeBoB MSG: Streaming thread running with Realtime scheduling, priority 74
> FreeBoB MSG: Registering capture port dev1c_MicIn1 left
>
> And ps says...
>   PID CLS RTPRIO  NI PRI %CPU STAT COMMAND
>  3423 TS       -   0  20  0.0 SLl  jackd
>  3423 TS       -   0  24  0.0 SLl  jackd
>  3423 TS       -   0  24  0.0 SLl  jackd
>  3423 TS       -   0  19  0.0 SLl  jackd
>  3423 FF      80   - 120  0.0 SLl  jackd
>  3423 FF      70   - 110  1.5 SLl  jackd
>  3423 FF      73   - 113  5.6 SLl  jackd
>  3423 FF      73   - 113  5.0 SLl  jackd
>  3423 FF      84   - 124  0.0 SLl  jackd
>  3423 FF      74   - 114  5.4 SLl  jackd
>
> Although, I just noticed now that some of those jackd threads aren't running with any RT prio at all. And, I also noticed that the little yellow "RT" in qjackctl isn't lit up either... Is that OK? Or is this a problem?

Several JACK threads are not supposed to run RT.

> I'm standing by and waiting to hear from the jackd developers before filing this with the Debian bug tracking system...
>
> And also waiting to hear back before I go out and blow $400 on a 2.4Ghz CPU....

I can't say what you should do.  Looks like it ought to work to me.
-- 
 joq