-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 12/28/2011 6:17 AM, Mike Galbraith wrote: > 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? this is 56% of kernel time.. of how much total time? (and are you using a system where tsc/lapic can be used, or are you using one of those boatanchors that need hpet?) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (MingW32) iQEcBAEBAgAGBQJO+xsmAAoJEEHdSxh4DVnEcDoIAK8Q0rTCNb/xX3mNm7QpLpIU kLXEHvv7Xk58TxKfOC7EDmD4EMdJxbebL6ZR7ol/J7mkQjnUjsFdGF1qF1TAW1Ph YdPV5liDMfwO+Aczj0ZdBBacuoIivUrFcwArKwonttwSB0dh1vyJU9VsRC7nTu4z eILaiYOr2pTBSKReYiQxr9u+1/zfmlwsENbbq/Z/JnbQYdf1y0ZNZ1kDF4zOwuHQ EdVu4o1RPRXwBlMI+6E3CaEyl6wACOGyoy3tsuHoR7Ax6YcwJUoDFmAVP8Bb+YE8 19AlRDnBwSCV+AaJ3qbaEdPdpX7Alp1h3fpdH8rZ/Ndu5DTeGDAuYI1HIDicZgA= =pSVy -----END PGP SIGNATURE----- -- 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
