[linux-audio-dev] Re: [Jackit-devel] Re: ANN: k_jack v0.0.0.5 and Mammut v0.15

Anders Torger torger at ludd.luth.se
Wed Jan 22 08:56:01 UTC 2003


On Wednesday 22 January 2003 13.00, Steve Harris wrote:
> On Wed, Jan 22, 2003 at 12:24:07 +0100, smoerk wrote:
> > jack is not usable at all for a normal end user. without a
> > low-latency kernel there a pops and klicks everywhere. then jackd
> > freezed my different debian installations several times (this may
> > kernel related, but a user don't care when other programs don't
> > freeze the machine). it consumes rediculous amounts of memory
> > (jackd uses 11MB, pd without gui 1,2MB).
>
> I run jackd as a normal user sometimes, you just have to turn the
> buffer size way up (I use 1024), just like in other non SCHED_FIFO
> apps. Yes, you will get pops and clicks without a patched kernel,
> this is true of all audio APIs under linux.
>
> The 11meg is mostly shared between all the applications, its the IPC
> space, and it may not even be mapped in normally, but I'm not sure
> about that, it depends on the exact semantics of mlockall(2).

If I remember correctly, mlockall and shared memory does not combine 
well, it seems like the blocks of shared memory is locked once for each 
process (thread?), thus you get a much higher memory use than you 
should. I had such problems with BruteFIR, but it is way back I looked 
into it so things may have changed (or I did something wrong in the 
first place).

/Anders Torger



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