On 06/17/2015 04:17 PM, Mike Galbraith wrote: > On Wed, 2015-06-17 at 10:33 +0200, Sebastian Andrzej Siewior wrote: >> wake_futex_pi() wakes the task before releasing the hash bucket lock >> (HB). The first thing the woken up task usually does is to acquire the >> lock which requires the HB lock. On SMP Systems this leads to blocking >> on the HB lock which is released by the owner shortly after. >> This patch rearranges the unlock path by first releasing the HB lock and >> then waking up the task. >> >> [bigeasy: redo ontop of lockless wake-queues] >> Signed-off-by: Thomas Gleixner <t...@linutronix.de> >> Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de> > > 4.1-rc8-rt4 contains this via 4.0-rt4, and seems fine on my 64 core > DL980. I ran a few iterations of futextests and stockfish, then mixed > two loops of futextest at different rt prios, with stockfish also rt, > and ltplight as tossed in as... crack filler. Box is still doing that, > is way too busy, but not griping about it.
There are two patches mostly doing the same thing. The patch posted here is a redo ontop of "lockless wake-queues". It does hb-unlock, wakeup, de-boost. The patch merged into -RT is the original approach not using "lockless wake-queues" and performing wakeup, hb-unlock, de-boost. I plan to get into -RT the final solution once it hits upstream. > > -Mike > Sebastian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
