Ingo Molnar wrote:
> i have released the -V0.7.30-2 Real-Time Preemption patch, which can be
> downloaded from the usual place:
> 
> 	http://redhat.com/~mingo/realtime-preempt/

Hi,
I´m seeing latencies of up to ~2000 microseconds. see attached traces
file for a small sample. I think I´m missing something obvious
config-wise but I don´t know what...
The ´load´ during the traces consisted of a kernel build in a
gnome-terminal, and 2 browser windows with a heavy site (Flash ads etc.)
in each. This load causes a >1 ms latency every 5 minutes on average.
After the kernel build ended the rate dropped dramatically to ~2 traces
an hour.
The traces were from V-0.7.29-5 but I´ve seen these latencies in all RT
kernels I tested (2.6.9-mm1-RT-V0.2 was the first). I´ll try V0.7.30-2 next.
The machine is a PIII 733 Mhz, 256MB RAM, IDE disks.
I attached the traces and a partial .config.
Relevant items in /proc/sys/kernel:

/proc/sys/kernel/kernel_preemption :
1
...
/proc/sys/kernel/osrelease :
2.6.10-rc2-mm2-V0.7.29-5
...
/proc/sys/kernel/panic :
0
/proc/sys/kernel/panic_on_oops :
0
/proc/sys/kernel/pid_max :
32768
/proc/sys/kernel/preempt_max_latency :
1737
/proc/sys/kernel/preempt_thresh :
1000
/proc/sys/kernel/preempt_wakeup_timing :
1
...
/proc/sys/kernel/real-root-dev :
0
/proc/sys/kernel/sem :
250     32000   32      128
/proc/sys/kernel/shmall :
2097152
/proc/sys/kernel/shmmax :
33554432
/proc/sys/kernel/shmmni :
4096
/proc/sys/kernel/sysrq :
1
/proc/sys/kernel/tainted :
0
/proc/sys/kernel/threads-max :
4095
/proc/sys/kernel/trace_enabled :
1
/proc/sys/kernel/trace_freerunning :
0
/proc/sys/kernel/trace_print_at_crash :
1
/proc/sys/kernel/trace_user_triggered :
0
/proc/sys/kernel/trace_verbose :
0
/proc/sys/kernel/unknown_nmi_panic :
0

Let me know if some more information is required.
Thank,
      Eran Mann