On Tue, 2011-12-27 at 10:20 +0100, Mike Galbraith wrote: > Quoting removal commit af5ab277ded04bd9bc6b048c5a2f0e7d70ef0867 > Historically, Linux has tried to make the regular timer tick on the > various CPUs not happen at the same time, to avoid contention on > xtime_lock. > > Nowadays, with the tickless kernel, this contention no longer happens > since time keeping and updating are done differently. In addition, > this skew is actually hurting power consumption in a measurable way on > many-core systems. > End quote Hm, nohz enabled, hogs burning up 60 of 64 cores. 56.11% [kernel] [k] ktime_get 5.54% [kernel] [k] scheduler_tick 4.02% [kernel] [k] cpuacct_charge 3.78% [kernel] [k] __rcu_pending 3.76% [kernel] [k] tick_sched_timer 3.42% [kernel] [k] native_write_msr_safe 1.58% [kernel] [k] run_timer_softirq 1.28% [kernel] [k] __schedule 1.21% [kernel] [k] apic_timer_interrupt 1.07% [kernel] [k] _raw_spin_lock 0.81% [kernel] [k] __switch_to 0.67% [kernel] [k] thread_return Maybe skew-me wants to become a boot option? -Mike -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
