i have released the -53-01 Real-Time Preemption patch, which can be downloaded from:
http://redhat.com/~mingo/realtime-preempt/ there are two new features in this release, which justified the jump from .52 to .53: - the inclusion of the High Resolution Timers patch, written by George Anzinger, and ported/improved/cleaned-up by Thomas Gleixner. - the inclusion of the RCU tasklist_lock patch from Paul McKenney. the HRT patch from George Anzinger is a crutial piece of real-time infrastructure. The version included in the -RT tree supports both PIT and local APIC timer driven variable-rate timer interrupts. Thomas Glexiner, besides porting it to PREEMPT_RT, cleaning it up, adding the local APIC timer support has also added the CONFIG_HIGH_RES_TIMERS_DYN_PRIO feature, which pushes priority inheritance into the high-res timer space. Furthermore, Thomas has extended nanosleep to use HR timers, if the task is RT. This makes it easier to test HRT functionality. NOTE: there's a new softirq, softirq-hrtimer (PID 8 on UP x86), which should be chrt-ed to higher than SCHED_FIFO-50 if HR timer interrupts are the most important latencies in the system. E.g.: chrt -f 90 -p 8 the RCU tasklist-lock patch is a small but important feature from Paul McKenney which enables good HRT latencies: the HRT patch, when using POSIX timers, would use a signal-sending codepath that depends on the tasklist_lock, and thus the (quite high) tasklist_lock latencies controlled the latency of HR timers - defeating much of the benefits of HR timers. With the RCU tasklist-lock the signal sending path is now RCU-read locked, with no locking dependency, and thus excellent worst-case latencies. given these changes, some (mostly build-related) regressions are to be expected. Only the x86 architecture is expected to work for now. to build a -V0.7.53-01 tree, the following patches should to be applied: http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.12.tar.bz2 http://kernel.org/pub/linux/kernel/v2.6/testing/patch-2.6.13-rc4.bz2 http://redhat.com/~mingo/realtime-preempt/realtime-preempt-2.6.13-rc4-RT-V0.7.53-01 patches, bugreports and any other feedback welcome, 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/
