Messages in this thread | | | From | John Stultz <> | Subject | [GIT PULL][PATCH 0/7] Reduce timekeeping lock hold time | Date | Mon, 27 Feb 2012 16:29:27 -0800 |
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Here is the second half of the timekeeping cleanups (the first half are already in -tip) as well as some changes to reduce the timekeeping lock hold times.
This work grew out of some of Eric Dumazet's and Thomas Gleixner's suggestions, after they noticed the xtime_lock hold time could be on the long side.
The basic idea is that we keep a shadow copy of the timekeeper stucture, which can be updated while readers are accessing the time. Then we only have to block readers as we switch to the newly updated structure.
I've done some limited testing, but it would be good to get this in -tip early, so we can be sure it gets enough testing before 3.4 is released.
CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com>
thanks -john
Thomas,
These patches are available in the git repository at: git://git.linaro.org/people/jstultz/linux.git fortglx/3.4/time
John Stultz (7): time: Condense timekeeper.xtime into xtime_sec time: Rework timekeeping functions to take timekeeper ptr as argument time: Split timekeeper lock into separate reader/writer locks time: Update timekeeper structure using a local shadow time: Shadow cycle_last in timekeeper structure time: Reduce timekeeper read lock hold time time: Convert the timekeeper's wlock to a raw_spin_lock
kernel/time/timekeeping.c | 414 ++++++++++++++++++++++++++------------------- 1 files changed, 243 insertions(+), 171 deletions(-)
-- 1.7.3.2.146.gca209
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