[PATCH 2/2] gta02-drm-defconfig: enable FCSE and PREEMPT

[Martix]

I didn't noticed any segfaults caused by FCSE with this patch version,
but if FCSE_MESSAGES isn't produce much overhead, it could be enabled.

I enabled PREEMPT_FLUSH, when using PREEMPT in expectation of better
response times. We need real application benchmarks to decide, what is
better for mobile phone/PDA like Neo FreeRunner.

What are DYNPID benefits?

2010/9/1 Gilles Chanteperdrix <gilles.chanteperdrix at xenomai.org>:
> On Wed, Sep 01, 2010 at 05:00:28PM +0200, Martix wrote:
>> Enables FCSE and PREEMPT to make low-latency system.
>>
>> 0002-gta02-drm-defconfig-enable-FCSE-and-PREEMPT.patch
>>
>> Sending as attachment to prevent line wrapping.
>
>> Enables FCSE and PREEMPT to make low-latency system.
>>
>> Signed-off-by: Martin Holec <martix.cz at gmail.com>
>> ---
>>  arch/arm/configs/gta02_drm_defconfig |   16 ++++++++++++----
>>  1 files changed, 12 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/arm/configs/gta02_drm_defconfig b/arch/arm/configs/gta02_drm_defconfig
>> index 39a933c..97bc636 100644
>> --- a/arch/arm/configs/gta02_drm_defconfig
>> +++ b/arch/arm/configs/gta02_drm_defconfig
>> @@ -1,7 +1,7 @@
>>  #
>>  # Automatically generated make config: don't edit
>> -# Linux kernel version: 2.6.32.16
>> -# Wed Jul 21 13:53:15 2010
>> +# Linux kernel version: 2.6.32.21
>> +# Wed Sep  1 16:43:37 2010
>>  #
>>  CONFIG_ARM=y
>>  CONFIG_HAVE_PWM=y
>> @@ -30,6 +30,7 @@ CONFIG_CONSTRUCTORS=y
>>  #
>>  CONFIG_EXPERIMENTAL=y
>>  CONFIG_BROKEN_ON_SMP=y
>> +CONFIG_LOCK_KERNEL=y
>>  CONFIG_INIT_ENV_ARG_LIMIT=32
>>  CONFIG_LOCALVERSION=""
>>  # CONFIG_LOCALVERSION_AUTO is not set
>> @@ -292,6 +293,13 @@ CONFIG_ARM_THUMB=y
>>  # CONFIG_CPU_DCACHE_DISABLE is not set
>>  # CONFIG_CPU_DCACHE_WRITETHROUGH is not set
>>  CONFIG_ARM_L1_CACHE_SHIFT=5
>> +CONFIG_ARM_FCSE=y
>> +# CONFIG_ARM_FCSE_GUARANTEED is not set
>> +CONFIG_ARM_FCSE_BEST_EFFORT=y
>> +# CONFIG_ARM_FCSE_DYNPID is not set
>> +CONFIG_ARM_FCSE_PREEMPT_FLUSH=y
>> +# CONFIG_ARM_FCSE_MESSAGES is not set
>> +# CONFIG_ARM_FCSE_DEBUG is not set
>
> It is not my business, but since I am CC'ed, I dare.
> You should probably enable FCSE_MESSAGES, as they may help you find
> issues caused by the FCSE patch (such as stack size limitaions).
>
> For performances issues, I would rather disable PREEMPT_FLUSH
> for lowest overhead (after all, caches flushes take less than 200 us, so
> this should not be a humanly noticeable delay)
>
> I would also test the DYNPID options with the applications you use.
>
> --
>                                            Gilles.
>