git: kernel - Reduce lwp_signotify() latency
dillon at crater.dragonflybsd.org
Sat Dec 19 13:08:50 PST 2015
Author: Matthew Dillon <dillon at apollo.backplane.com>
Date: Sat Dec 19 13:05:55 2015 -0800
kernel - Reduce lwp_signotify() latency
* lwp_signotify() was not issuing an IPI to another cpu if the target
thread was in a run state, preventing that thread from seeing the
signal for roughly one scheduler tick.
* This interferes with programs like qemu which depend on signaling
between threads for the timer tick and numerous other things,
causing timers to behave poorly.
* Fix by issuing the necessary IPI.
Reported-by: Imre Vadasz
Testing-by: Imre Vadasz (+ a bug fix to the original patch)
Summary of changes:
sys/kern/kern_sig.c | 30 +++++++++++++++++++++---------
1 file changed, 21 insertions(+), 9 deletions(-)
DragonFly BSD source repository
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