i have released the -V0.7.47-20 Real-Time Preemption patch, which can be
downloaded from the usual place:
http://redhat.com/~mingo/realtime-preempt/
i've implemented two new features:
- new debugging feature: CONFIG_DEBUG_RT_LOCKING_MODE, which
adds the /proc/sys/kernel/preempt_locks flag (default: 0). This way
the 'locking model' can be switched runtime - very useful for
debugging and profiling. Value 0 means that all spinlocks and rwlocks
are implemented via raw spinlocks/rwlocks. (which disable preemption,
increase latency, but improve throughput) Value 1 means the kernel
will fully preempt all locks again. (NOTE: the only safe runtime
switching of the locking model can be done while the system is idle,
so i've implemented the flag via two flags where the idle thread
propagates the new value from the user-flag to the kernel-flag. You
should put a "sleep 1" into scripts that switch the locking mode, to
guarantee that the new flag value is picked up.)
- performance feature: i've implemented a new scheduler feature called
'delayed preemption', which turns sync wakeups into guaranteed
wakeups, while preserving their workload-batching properties. A
delayed preemption request is implemented via the
TIF_NEED_RESCHED_DELAYED flag, which runs in parallel to the
"immediate preemption" TIF_NEED_RESCHED flag. If this works out fine
then it will be a suitable replacement for the upstream sync-wakeups
facility as well.
delayed preemption already improved the performance of 'hackbench' under
PREEMPT_RT quite signifiantly.
to build a -V0.7.47-20 tree, the following patches have to be applied:
http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.11.tar.bz2
http://kernel.org/pub/linux/kernel/v2.6/testing/patch-2.6.12-rc6.bz2
http://redhat.com/~mingo/realtime-preempt/realtime-preempt-2.6.12-rc6-V0.7.47-20
Ingo
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
