Re: [Xenomai] Fwd: Kernel Compilation Problems

[Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>]

On 01/31/2014 01:05 AM, Andy Pugh wrote:
> On 19 January 2014 13:42, Gilles Chanteperdrix
> <gilles.chanteperdrix@xenomai.org> wrote:
> 
>>> Could you try the following patch to see if it improves anything?
>>
>> Sorry, wrong patch version. Please try this one instead:
> 
> The patch appears to reduce the latency to about 60uS.
> 
> I thought that setenv isolcpus=0 had had an effect, as I opened
> Firefox and didn't see max latency increase over the 45uS it was at,
> but then opening Chromium too pushed it up to 60uS.
> 
> Does Xenomai automatically choose the isolated CPU, or is some config needed?
> 
> In fact, how do I tell that I have an isolated CPU?

Use the xeno_hal.supported_cpus parameter, it is a bitfield, so 1 is for
cpu 0.

There is more we can do to improve performances on imx6:
- enable more features in the L2 cache auxiliary control register (the
value of this register is passed to the l2x0_init function, and
currently imx6 passes all 0)
- use the L2 cache "lockdown by master" feature, to reserve several
cache ways to the core where xenomai runs.

l2x0_init prints the value of the auxiliary control register at boot,
could you show me the boot logs you get to see which bits exactly are
already enabled?

Regards.

-- 
                                                                Gilles.