[0/3] reduce latency of synchronize_rcu()

Message

Uladzislau Rezki Oct. 25, 2023, 2:09 p.m. UTC

Here is a small series that tends to reduce a waiting time of
synchronize_rcu() call. Please note, this is only limited to
a "normal" version.

As for performance figures, i used real test cases and a synthetic.
For example
 - camera app launch time on our Android device is reduced by 9-13 percent;
 - loading 100 kernel modules also get improved by 10-12 percent;
 - synthetic gives 30 and higher percentage of boost.

Uladzislau Rezki (Sony) (3):
  rcu: Reduce synchronize_rcu() waiting time
  rcu: Add a trace event for synchronize_rcu_normal()
  doc: Add rcutree.rcu_normal_wake_from_gp to kernel-parameters.txt

 .../admin-guide/kernel-parameters.txt         |  12 ++
 include/trace/events/rcu.h                    |  27 ++++
 kernel/rcu/tree.c                             | 152 +++++++++++++++++-
 kernel/rcu/tree_exp.h                         |   2 +-
 4 files changed, 191 insertions(+), 2 deletions(-)