Hi, Here is a first attempt at providing support for lazy callbacks on non-offloaded CPUs. I have measured interesting results on my machine when it is mostly idle (just an idle ssh connection kept alive) with a gain of +10% idle time. This needs more serious testing though, especially to make sure that no performance regression is introduced. Also I have only mildly tested on NOCB (eg: no rcutorture yet), so I might have broken something. Finally it's also possible that the idle time improvement is due to me introducing a bug :) The patches 1-5 can be considered independently from the rest. Frederic Weisbecker (9): rcu: Assume IRQS disabled from rcu_report_dead() rcu: Use rcu_segcblist_segempty() instead of open coding it rcu: Rename jiffies_till_flush to jiffies_lazy_flush rcu: Introduce lazy queue's own qhimark rcu: Add rcutree.lazy_enabled boot parameter rcu/nocb: Rename was_alldone to was_pending rcu: Implement lazyness on the main segcblist level rcu: Make segcblist flags test strict rcu: Support lazy callbacks with CONFIG_RCU_NOCB=n .../admin-guide/kernel-parameters.txt | 5 + include/linux/rcu_segcblist.h | 13 +- kernel/rcu/Kconfig | 2 +- kernel/rcu/rcu.h | 8 +- kernel/rcu/rcu_segcblist.c | 44 ++- kernel/rcu/rcu_segcblist.h | 32 +- kernel/rcu/rcuscale.c | 6 +- kernel/rcu/tree.c | 272 +++++++++++++++-- kernel/rcu/tree.h | 9 +- kernel/rcu/tree_nocb.h | 285 +++++------------- 10 files changed, 425 insertions(+), 251 deletions(-) -- 2.40.1
