Re: [PATCH]sched: Isochronous class v2 for unprivileged soft rt scheduling

["Jack O'Quin" <joq@io.com>]

Con Kolivas <kernel@kolivas.org> writes:

> Jack O'Quin wrote:
>> Outstanding.  How do you get rid of that checkerboard grey
>> background in the graphs?
>
>> Con Kolivas <kernel@kolivas.org> writes:
> Funny; that's the script you sent me so... beats me?

It's just one of the many things I don't understand about graphics.  

If I look at those png's locally (with gimp or gqview) they have a
dark grey checkerboard background.  If I look at them on the web (with
galeon), the background is white.  Go figure.  Maybe the file has no
background?  I dunno.

>> Looking at the graphs, your system has a substantial 4 to 6 msec delay
>> on approximately 40 second intervals, regardless of which scheduling
>> class or how many clients you run.  I'm guessing this is a recurring
>> long code path in the kernel and not a scheduling artifact at all.
>
> Probably. No matter what I do the hard drive seems to keep trying to
> spin down. Might be related.

I was misreading the x-axis.  They're actually every 20 sec.  My
system isn't doing that.

> in the background:
> while true ; do make clean && make ; done
>
> SCHED_ISO with 40 clients:
> *********************************************
> Timeout Count . . . . . . . . :(    0)
> XRUN Count  . . . . . . . . . :     3
> Delay Count (>spare time) . . :    20
> Delay Count (>1000 usecs) . . :     0
> Delay Maximum . . . . . . . . :  5841   usecs
> Cycle Maximum . . . . . . . . :   891   usecs
> Average DSP Load. . . . . . . :    34.1 %
> Average CPU System Load . . . :    10.7 %
> Average CPU User Load . . . . :    87.8 %
> Average CPU Nice Load . . . . :     0.0 %
> Average CPU I/O Wait Load . . :     0.7 %
> Average CPU IRQ Load  . . . . :     0.8 %
> Average CPU Soft-IRQ Load . . :     0.0 %
> Average Interrupt Rate  . . . :  1711.4 /sec
> Average Context-Switch Rate . : 20751.6 /sec
> *********************************************

The scheduler seems to be working great.  

You're really getting hammered with those periodic 6 msec delays,
though.  The basic audio cycle is only 1.45 msec.
-- 
  joq