Re: [Xenomai-core] XENO_OPT_SYS_STACKPOOLSZ vs. switchtest

[Jan Kiszka <jan.kiszka@domain.hid>]

Gilles Chanteperdrix wrote:
> Jan Kiszka wrote:
>> Gilles Chanteperdrix wrote:
>>> Jan Kiszka wrote:
>>>> Gilles Chanteperdrix wrote:
>>>>> Jan Kiszka wrote:
>>>>>> Hi Gilles,
>>>>>>
>>>>>> how much XENO_OPT_SYS_STACKPOOLSZ do I need to run switchtest for
>>>>>> default settings? At least on x86-64, the default 32K is not enough.
>>>>>> Unless we talk about GB ;), maybe it makes sense to adjust the default
>>>>>> size accordingly.
>>>>> It depends on the arguments you pass to switchtest.
>>>> None, ie. the default settings.
>>> Then 6 kernel-space tasks are created. Since switchtest is not the
>> 6*4 is 20k... Ah, the well-known allocator overhead, I guess. Will try
>> with >= 40k.
>>
>>> average use of Xenomai, and is supposed to be used only for validating
>>> the context/FPU switches, I would not change XENO_OPT_SYS_STACKPOOL_SZ,
>>> maybe only add a clear message when creation of kernel-space tasks fails.
>> Well, isn't the switchtest part of xeno-test? Would be unfortunate to
>> require a kernel rebuild just for running the standard tests. I think we
>> don't loose much by slightly increasing the stack to, say, 64K on 32 bit
>> and 128K on 64 bit archs.
> 
> The kernel rebuild is already required since the switchtest driver is
> not compiled by default.

Even if it were default off (which it isn't), requiring a second rebuild
due to this implicit dependency would remain, well, unfortunate.

I will propose a Kconfig adjustment later.

Jan

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