Messages in this thread | | | Date | Thu, 27 Feb 2014 17:27:04 -0800 | From | "Paul E. McKenney" <> | Subject | [GIT PULL timers] Timer-wheel bandaids^Wcommits for 3.15 |
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Hello, Thomas and Ingo,
This pull request contains latency bandaids^Woptimizations to the timer-wheel code that are useful in conjunction with NO_HZ_FULL Kconfig option. These optimizations reduce the jiffy-by-jiffy looping in cases where there is either zero or one timers in the timer wheel, which is a common case for NO_HZ_FULL "worker" CPUs that run almost entirely in usermode for a single task.
This is of course no substitute for a more extensive reworking of the timer-wheel code, but it does provide some simple patches that can provide significant latency improvements for NO_HZ_FULL systems that have CPUs that very rarely enter the kernel.
Thanx, Paul
These changes since commit 849401b66d305f3feb75b6db7459b95ad190552a:
tick: Fixup more fallout from hrtimer broadcast mode (2014-02-09 15:11:47 +0100)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu.git timers.2014.02.25a
for you to fetch changes up to aea369b959bef10d235cd0714789cd8b0fe170b8:
timers: Make internal_add_timer() update ->next_timer if ->active_timers == 0 (2014-02-25 12:39:01 -0800)
---------------------------------------------------------------- Oleg Nesterov (1): timers: Make internal_add_timer() update ->next_timer if ->active_timers == 0
Paul E. McKenney (4): timers: Track total number of timers in list timers: Reduce __run_timers() latency for empty list timers: Reduce future __run_timers() latency for newly emptied list timers: Reduce future __run_timers() latency for first add to empty list
kernel/timer.c | 30 ++++++++++++++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-)
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