Re: Real-Time Preemption, -RT-2.6.10-rc2-mm3-V0.7.31-7

[Ingo Molnar <mingo@elte.hu>]

* Rui Nuno Capela <rncbc@rncbc.org> wrote:

>   config-2.6.10-rc2-mm3-RT-V0.7.31-7.gz
>      - kernel configuration as of my laptop, taken from /proc/config.gz

Here are some .config suggestion to reduce tracing costs. Here's the
relevant portion of your .config:

 CONFIG_DEBUG_KERNEL=y
 CONFIG_MAGIC_SYSRQ=y
 # CONFIG_SCHEDSTATS is not set
 # CONFIG_DEBUG_SLAB is not set
 CONFIG_DEBUG_PREEMPT=y
 CONFIG_WAKEUP_TIMING=y
 CONFIG_PREEMPT_TRACE=y
 CONFIG_CRITICAL_PREEMPT_TIMING=y
 CONFIG_CRITICAL_IRQSOFF_TIMING=y
 CONFIG_CRITICAL_TIMING=y
 CONFIG_LATENCY_TIMING=y
 CONFIG_LATENCY_TRACE=y
 CONFIG_MCOUNT=y
 CONFIG_RT_DEADLOCK_DETECT=y
 # CONFIG_DEBUG_KOBJECT is not set
 CONFIG_DEBUG_BUGVERBOSE=y
 # CONFIG_DEBUG_INFO is not set
 CONFIG_FRAME_POINTER=y
 CONFIG_EARLY_PRINTK=y
 CONFIG_DEBUG_STACKOVERFLOW=y

i'd suggest to use the following one:

 CONFIG_DEBUG_KERNEL=y
 CONFIG_MAGIC_SYSRQ=y
 # CONFIG_SCHEDSTATS is not set
 # CONFIG_DEBUG_SLAB is not set
 # CONFIG_DEBUG_PREEMPT is not set
 # CONFIG_DEBUG_SPINLOCK_SLEEP is not set
 CONFIG_WAKEUP_TIMING=y
 # CONFIG_CRITICAL_PREEMPT_TIMING is not set
 # CONFIG_CRITICAL_IRQSOFF_TIMING is not set
 CONFIG_LATENCY_TIMING=y
 CONFIG_LATENCY_TRACE=y
 CONFIG_MCOUNT=y
 # CONFIG_RT_DEADLOCK_DETECT is not set
 # CONFIG_DEBUG_KOBJECT is not set
 CONFIG_DEBUG_BUGVERBOSE=y
 # CONFIG_DEBUG_INFO is not set
 CONFIG_FRAME_POINTER=y
 CONFIG_EARLY_PRINTK=y
 # CONFIG_DEBUG_STACKOVERFLOW is not set

especially PREEMPT_TIMING, IRQSOFF_TIMING and RT_DEADLOCK_DETECT are
quite expensive options.

	Ingo