Messages in this thread | | | Date | Wed, 27 Oct 2004 02:15:42 +0200 | From | Ingo Molnar <> | Subject | [patch] Real-Time Preemption, -RT-2.6.9-mm1-V0.3 |
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i have released the -V0.3 Real-Time Preemption patch, which can be downloaded from:
http://redhat.com/~mingo/realtime-preempt/
this is a fixes-only release, but still experimental.
this release should fix a number of bugs that were reported for the V0 series: the futex.c assert, the lockups and the 'slowdown problem'.
The slowdown problem was an architectural issue that surfaced sometime around U10 and increased in prominence as the the number of mutexes increased and the number of spinlocks decreased. The futex.c assert was related to this architectural issue as well, and most of the lockups reported were i believe livelocks caused by the same issue. Also, the scheduler path had an easy-to-trigger deadlock that often just silently locked up.
some of the networking lockups might be related to this issue too, but i think PREEMPT_REALTIME still has separate lock odering issues within the networking code. Please re-report any deadlock-tracer asserts that you might encounter.
Changes since -V0.2:
- HEAP_SIZE fix from Karsten Wiese
- fix hdparm-triggered debugging message reported by Mark H Johnson
- fixed mutex related preemption to not impact the task state, just like a normal spinlock does. This necessiated the introduction of TASK_RUNNING_MUTEX handling and related kernel infrastructure. This framework avoids spurious wakeups done by mutex handling by isolating the state changes done by normal wakeups vs. the state changes caused by the mutex code.
- added per-CPU deschedule threads. This fixes a deadlock scenario and it is also much faster than keventd.
- fix debugging message upon console unblanking
to create a -V0.3 tree from scratch, the patching order is:
http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.9.tar.bz2 + http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.9/2.6.9-mm1/2.6.9-mm1.bz2 + http://redhat.com/~mingo/realtime-preempt/realtime-preempt-2.6.9-mm1-V0.3
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