Hi,
This is a follow up series while reviewing Waiman's reader-owned
state work[1]. While I have based it on -tip instead of that change,
I can certainly rebase the series in some future iteration.
Changes are mainly around reader-waiter optimizations, in no particular
order. Has passed numerous DB benchmarks without things falling apart
for a 8 core Westmere doing page allocations (page_test) in aim9:
aim9
4.6-rc6 4.6-rc6
rwsemv2
Min page_test 378167.89 ( 0.00%) 382613.33 ( 1.18%)
Min exec_test 499.00 ( 0.00%) 502.67 ( 0.74%)
Min fork_test 3395.47 ( 0.00%) 3537.64 ( 4.19%)
Hmean page_test 395433.06 ( 0.00%) 414693.68 ( 4.87%)
Hmean exec_test 499.67 ( 0.00%) 505.30 ( 1.13%)
Hmean fork_test 3504.22 ( 0.00%) 3594.95 ( 2.59%)
Stddev page_test 17426.57 ( 0.00%) 26649.92 (-52.93%)
Stddev exec_test 0.47 ( 0.00%) 1.41 (-199.05%)
Stddev fork_test 63.74 ( 0.00%) 32.59 ( 48.86%)
Max page_test 429873.33 ( 0.00%) 456960.00 ( 6.30%)
Max exec_test 500.33 ( 0.00%) 507.66 ( 1.47%)
Max fork_test 3653.33 ( 0.00%) 3650.90 ( -0.07%)
4.6-rc6 4.6-rc6
rwsemv2
User 1.12 0.04
System 0.23 0.04
Elapsed 727.27 721.98
[1] http://permalink.gmane.org/gmane.linux.kernel/2216743
Thanks!
Davidlohr Bueso (4):
locking/rwsem: Avoid stale ->count for rwsem_down_write_failed()
locking/rwsem: Drop superfluous waiter refcount
locking/rwsem: Enable lockless waiter wakeup(s)
locking/rwsem: Rework zeroing reader waiter->task
kernel/locking/rwsem-xadd.c | 74 ++++++++++++++++++++++++++-------------------
1 file changed, 43 insertions(+), 31 deletions(-)
--
2.8.1
