my message probably should have read: "I am not aware of an RT-PREEMPT kernel for the BB, but I think it is possible to build one now based on the patch below and it would be great if somebody actually built one and reported figures"
"hard rt" meaning Xenomai? those we have - on the order of 40-50uS -- now if somebody went around and outlined an RTAPI patch to pass the actual invocation time to RT threads as discussed in Wichita, we could go ahead and timebase-correct some of the code which relies on the "assumed time equals actual time" assumption, like motion and pid comps, then we likely could put the latency discussion to rest for the the better part (I admit it is fun to compare latency though, it's a bit like 'my motorbike is tuned grandiously better than your motorbike' - nevermind the 10mpH speed limit ;) - Michael Am 11.07.2013 um 13:44 schrieb EBo <[email protected]>: > Does anyone have latency tests for the BB with RT-PREEMPT and possibly > the hard RT? > > Thanks and best regards, > > EBo -- > > On Jul 11 2013 1:46 AM, Michael Haberler wrote: >> heads up for beagleBone users and folks dabbling with 3.8-based >> kernels (most likely for ARM platforms): >> >> this patch seems to fit the current 3.8-based BeagleBone kernels, >> meaning it should be possible to create an RT-PREEMPT kernel for the >> BB >> >> - Michael >> >> >> Anfang der weitergeleiteten Nachricht: >> >>> Von: Sebastian Andrzej Siewior <[email protected]> >>> Betreff: [ANNOUNCE] 3.8.13-rt14 >>> Datum: 11. Juli 2013 09:38:58 MESZ >>> An: linux-rt-users <[email protected]> >>> Kopie: LKML <[email protected]>, Thomas Gleixner >>> <[email protected]>, [email protected], John Kacur >>> <[email protected]> >>> >>> Dear RT Folks, >>> >>> I'm pleased to announce the 3.8.13-rt14 release. >>> >>> changes since v3.8.13-rt13: >>> - added a patch from Uwe Kleine-König to fix the UP breakage >>> introduced by >>> the recent s/sbin spinlocks/raw_spin_lock/ change. >>> - added a fix for a livelock of workqueue vs ata-piix. Found by >>> Carsten >>> Emde, patch proposed by Thomas Gleixner. >>> >>> The delta patch against v3.8.13-rt13 is appended below and can be >>> found here: >>> >>> >>> https://www.kernel.org/pub/linux/kernel/projects/rt/3.8/incr/patch-3.8.13-rt13-rt14.patch.xz >>> >>> The RT patch against 3.8.13 can be found here: >>> >>> >>> https://www.kernel.org/pub/linux/kernel/projects/rt/3.8/patch-3.8.13-rt14.patch.xz >>> >>> The split quilt queue is available at: >>> >>> >>> https://www.kernel.org/pub/linux/kernel/projects/rt/3.8/patches-3.8.13-rt14.tar.xz >>> >>> Sebastian >>> >>> diff --git a/include/linux/list_bl.h b/include/linux/list_bl.h >>> index ddfd46a..becd7a6 100644 >>> --- a/include/linux/list_bl.h >>> +++ b/include/linux/list_bl.h >>> @@ -131,8 +131,10 @@ static inline void hlist_bl_lock(struct >>> hlist_bl_head *b) >>> bit_spin_lock(0, (unsigned long *)b); >>> #else >>> raw_spin_lock(&b->lock); >>> +#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) >>> __set_bit(0, (unsigned long *)b); >>> #endif >>> +#endif >>> } >>> >>> static inline void hlist_bl_unlock(struct hlist_bl_head *b) >>> @@ -140,7 +142,9 @@ static inline void hlist_bl_unlock(struct >>> hlist_bl_head *b) >>> #ifndef CONFIG_PREEMPT_RT_BASE >>> __bit_spin_unlock(0, (unsigned long *)b); >>> #else >>> +#if defined(CONFIG_SMP) || defined(CONFIG_DEBUG_SPINLOCK) >>> __clear_bit(0, (unsigned long *)b); >>> +#endif >>> raw_spin_unlock(&b->lock); >>> #endif >>> } >>> diff --git a/kernel/workqueue.c b/kernel/workqueue.c >>> index 0d49ddf..99855b3 100644 >>> --- a/kernel/workqueue.c >>> +++ b/kernel/workqueue.c >>> @@ -42,6 +42,7 @@ >>> #include <linux/lockdep.h> >>> #include <linux/idr.h> >>> #include <linux/locallock.h> >>> +#include <linux/delay.h> >>> >>> #include "workqueue_sched.h" >>> >>> @@ -1157,7 +1158,7 @@ static int try_to_grab_pending(struct >>> work_struct *work, bool is_dwork, >>> local_unlock_irqrestore(pendingb_lock, *flags); >>> if (work_is_canceling(work)) >>> return -ENOENT; >>> - cpu_relax(); >>> + cpu_chill(); >>> return -EAGAIN; >>> } >>> >>> diff --git a/localversion-rt b/localversion-rt >>> index 9f7d0bd..08b3e75 100644 >>> --- a/localversion-rt >>> +++ b/localversion-rt >>> @@ -1 +1 @@ >>> --rt13 >>> +-rt14 >>> -- >>> To unsubscribe from this list: send the line "unsubscribe >>> linux-rt-users" in >>> the body of a message to [email protected] >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> >> >> ------------------------------------------------------------------------------ >> See everything from the browser to the database with AppDynamics >> Get end-to-end visibility with application monitoring from >> AppDynamics >> Isolate bottlenecks and diagnose root cause in seconds. >> Start your free trial of AppDynamics Pro today! >> >> http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk >> _______________________________________________ >> Emc-developers mailing list >> [email protected] >> https://lists.sourceforge.net/lists/listinfo/emc-developers > > > ------------------------------------------------------------------------------ > See everything from the browser to the database with AppDynamics > Get end-to-end visibility with application monitoring from AppDynamics > Isolate bottlenecks and diagnose root cause in seconds. > Start your free trial of AppDynamics Pro today! > http://pubads.g.doubleclick.net/gampad/clk?id=48808831&iu=/4140/ostg.clktrk > _______________________________________________ > Emc-developers mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-developers ------------------------------------------------------------------------------ See everything from the browser to the database with AppDynamics Get end-to-end visibility with application monitoring from AppDynamics Isolate bottlenecks and diagnose root cause in seconds. 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