Messages in this thread | | | From | Frederic Weisbecker <> | Subject | [RFC][PATCH 00/41] Nohz cpusets v3 (adaptive tickless kernel) | Date | Tue, 1 May 2012 01:54:34 +0200 |
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Hi,
A summary of what this is about can be found here: https://lkml.org/lkml/2011/8/15/245
Changes since v2:
* Correctly handle update of the cpuset mask when the nohz flag is set (courtesy of Hakan Akkan)
* Handle rq clock. This introduces a new update_nohz_rq_clock() helper that sites which make use of rq->clock can call if they want to ensure the rq clock doesn't have a stale value due to the targeted CPU beeing tickless. If it's tickless, it's not maintaining the rq clock by calling scheduler_tick()->update_rq_clock() periodically. I think I've added this manual call to every callsites that needed it. I may have missed some though, or we may forget to handle tickless CPUs in future code. So I think we need to add some automated debug checks to catch that.
* Fix a warning reported by Gilad Ben Yossef: we flush the time on pre-schedule and then the tick is restarted from an IPI before we do it manually on post-schedule. From there we try to flush the time again but ts->jiffies_saved_whence is set to SAVED_NONE because we already flushed the time. This was triggering a spurious warning.
Still a lot to do. I'm now maintaining the TODO list there: https://github.com/fweisbec/linux-dynticks/wiki/TODO
The git branch can be fetched from:
git://github.com/fweisbec/linux-dynticks.git nohz/cpuset-v3
Frederic Weisbecker (40): nohz: Separate idle sleeping time accounting from nohz logic nohz: Make nohz API agnostic against idle ticks cputime accounting nohz: Rename ts->idle_tick to ts->last_tick nohz: Move nohz load balancer selection into idle logic nohz: Move ts->idle_calls incrementation into strict idle logic nohz: Move next idle expiry time record into idle logic area cpuset: Set up interface for nohz flag nohz: Try not to give the timekeeping duty to an adaptive tickless cpu x86: New cpuset nohz irq vector nohz: Adaptive tick stop and restart on nohz cpuset nohz/cpuset: Don't turn off the tick if rcu needs it nohz/cpuset: Wake up adaptive nohz CPU when a timer gets enqueued nohz/cpuset: Don't stop the tick if posix cpu timers are running nohz/cpuset: Restart tick when nohz flag is cleared on cpuset nohz/cpuset: Restart the tick if printk needs it rcu: Restart the tick on non-responding adaptive nohz CPUs rcu: Restart tick if we enqueue a callback in a nohz/cpuset CPU nohz: Generalize tickless cpu time accounting nohz/cpuset: Account user and system times in adaptive nohz mode nohz/cpuset: New API to flush cputimes on nohz cpusets nohz/cpuset: Flush cputime on threads in nohz cpusets when waiting leader nohz/cpuset: Flush cputimes on procfs stat file read nohz/cpuset: Flush cputimes for getrusage() and times() syscalls x86: Syscall hooks for nohz cpusets x86: Exception hooks for nohz cpusets x86: Add adaptive tickless hooks on do_notify_resume() nohz: Don't restart the tick before scheduling to idle sched: Comment on rq->clock correctness in ttwu_do_wakeup() in nohz sched: Update rq clock on nohz CPU before migrating tasks sched: Update rq clock on nohz CPU before setting fair group shares sched: Update rq clock on tickless CPUs before calling check_preempt_curr() sched: Update rq clock earlier in unthrottle_cfs_rq sched: Update clock of nohz busiest rq before balancing sched: Update rq clock before idle balancing sched: Update nohz rq clock before searching busiest group on load balancing rcu: New rcu_user_enter() and rcu_user_exit() APIs rcu: New rcu_user_enter_irq() and rcu_user_exit_irq() APIs rcu: Switch to extended quiescent state in userspace from nohz cpuset nohz: Exit RCU idle mode when we schedule before resuming userspace nohz/cpuset: Disable under some configs
Hakan Akkan (1): nohz/cpuset: enable addition&removal of cpus while in adaptive nohz mode
arch/Kconfig | 3 + arch/x86/Kconfig | 1 + arch/x86/include/asm/entry_arch.h | 3 + arch/x86/include/asm/hw_irq.h | 7 + arch/x86/include/asm/irq_vectors.h | 2 + arch/x86/include/asm/smp.h | 11 + arch/x86/include/asm/thread_info.h | 10 +- arch/x86/kernel/entry_64.S | 12 +- arch/x86/kernel/irqinit.c | 4 + arch/x86/kernel/ptrace.c | 10 + arch/x86/kernel/signal.c | 3 + arch/x86/kernel/smp.c | 26 ++ arch/x86/kernel/traps.c | 20 +- arch/x86/mm/fault.c | 13 +- fs/proc/array.c | 2 + include/linux/cpuset.h | 29 ++ include/linux/kernel_stat.h | 2 + include/linux/posix-timers.h | 1 + include/linux/rcupdate.h | 8 + include/linux/sched.h | 10 +- include/linux/tick.h | 75 ++++-- init/Kconfig | 8 + kernel/cpuset.c | 141 +++++++++- kernel/exit.c | 8 + kernel/posix-cpu-timers.c | 12 + kernel/printk.c | 15 +- kernel/rcutree.c | 150 ++++++++-- kernel/sched/core.c | 112 ++++++++- kernel/sched/fair.c | 39 +++- kernel/sched/sched.h | 29 ++ kernel/softirq.c | 6 +- kernel/sys.c | 6 + kernel/time/tick-sched.c | 542 +++++++++++++++++++++++++++++------- kernel/time/timer_list.c | 7 +- kernel/timer.c | 2 +- 35 files changed, 1148 insertions(+), 181 deletions(-)
-- 1.7.5.4
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