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Message #177535
[Bug 1579278] Re: Consider changing default CPU frequency scaling governor back to "performance" (Ubuntu Server)
Ah thanks. So maybe /etc/init.d/ondemand should have something to
override or disable it (say DISABLE=1 in /etc/default/ondemand)?
Looking at it currently, it seems to prefer governors in this order -
interactive, ondemand, powersave. Even an option in
/etc/default/ondemand to specify the preferred would be nice (e.g.
PREFERRED_GOVERNOR=performance).
** Also affects: sysvinit (Ubuntu)
Importance: Undecided
Status: New
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https://bugs.launchpad.net/bugs/1579278
Title:
Consider changing default CPU frequency scaling governor back to
"performance" (Ubuntu Server)
Status in linux package in Ubuntu:
Invalid
Status in sysvinit package in Ubuntu:
New
Status in linux source package in Xenial:
Invalid
Status in sysvinit source package in Xenial:
New
Bug description:
Hi,
With the new Ubuntu archive servers, we saw constantly high load and
after some tinkering, we found that it was mostly CPUs being woken up
to see if they should enter idle states. Changing the CPU frequency
scaling governor to "performance" saw a considerable drop.
Perf report using the following commands:
| perf record -g -a sleep 10
| perf report
| Samples: 287K of event 'cycles:pp', Event count (approx.): 124776998906
| Children Self Command Shared Object Symbol
| + 55.24% 0.20% swapper [kernel.kallsyms] [k] cpu_startup_entry
| + 53.51% 0.00% swapper [kernel.kallsyms] [k] start_secondary
| + 53.02% 0.08% swapper [kernel.kallsyms] [k] call_cpuidle
| + 52.94% 0.02% swapper [kernel.kallsyms] [k] cpuidle_enter
| + 31.81% 0.67% swapper [kernel.kallsyms] [k] cpuidle_enter_state
| + 29.59% 0.12% swapper [kernel.kallsyms] [k] acpi_idle_enter
| + 29.45% 0.05% swapper [kernel.kallsyms] [k] acpi_idle_do_entry
| + 29.43% 29.43% swapper [kernel.kallsyms] [k] acpi_processor_ffh_cstate_enter
| + 20.51% 0.04% swapper [kernel.kallsyms] [k] ret_from_intr
| + 20.47% 0.12% swapper [kernel.kallsyms] [k] do_IRQ
| + 19.30% 0.07% swapper [kernel.kallsyms] [k] irq_exit
| + 19.18% 0.07% apache2 [kernel.kallsyms] [k] entry_SYSCALL_64_fastpath
| + 18.80% 0.17% swapper [kernel.kallsyms] [k] __do_softirq
| + 16.45% 0.11% swapper [kernel.kallsyms] [k] net_rx_action
| + 16.25% 0.43% swapper [kernel.kallsyms] [k] be_poll
| + 14.74% 0.21% swapper [kernel.kallsyms] [k] be_process_rx
| + 13.61% 0.07% swapper [kernel.kallsyms] [k] napi_gro_frags
| + 12.58% 0.04% swapper [kernel.kallsyms] [k] netif_receive_skb_internal
| + 12.48% 0.03% swapper [kernel.kallsyms] [k] __netif_receive_skb
| + 12.42% 0.24% swapper [kernel.kallsyms] [k] __netif_receive_skb_core
| + 12.41% 0.00% apache2 [unknown] [k] 0x00007f27983b5028
| + 12.41% 0.00% apache2 [unknown] [k] 0x00007f2798369028
| + 11.49% 0.16% swapper [kernel.kallsyms] [k] ip_rcv
| + 11.29% 0.09% swapper [kernel.kallsyms] [k] ip_rcv_finish
| + 10.77% 0.05% swapper [kernel.kallsyms] [k] ip_local_deliver
| + 10.70% 0.06% swapper [kernel.kallsyms] [k] ip_local_deliver_finish
| + 10.55% 0.22% swapper [kernel.kallsyms] [k] tcp_v4_rcv
| + 10.10% 0.00% apache2 [unknown] [k] 0000000000000000
| + 10.01% 0.04% swapper [kernel.kallsyms] [k] tcp_v4_do_rcv
Expanding in a few of those, you'll see:
| - 55.24% 0.20% swapper [kernel.kallsyms] [k] cpu_startup_entry
| - 55.04% cpu_startup_entry
| - 52.98% call_cpuidle
| + 52.93% cpuidle_enter
| + 0.00% ret_from_intr
| 0.00% cpuidle_enter_state
| 0.00% irq_entries_start
| + 1.14% cpuidle_select
| + 0.47% schedule_preempt_disabled
| 0.10% rcu_idle_enter
| 0.09% rcu_idle_exit
| + 0.05% ret_from_intr
| + 0.05% tick_nohz_idle_enter
| + 0.04% arch_cpu_idle_enter
| 0.02% cpuidle_enter
| 0.02% tick_check_broadcast_expired
| + 0.01% cpuidle_reflect
| 0.01% menu_reflect
| 0.01% atomic_notifier_call_chain
| 0.01% local_touch_nmi
| 0.01% cpuidle_not_available
| 0.01% menu_select
| 0.01% cpuidle_get_cpu_driver
| + 0.01% tick_nohz_idle_exit
| + 0.01% sched_ttwu_pending
| 0.00% set_cpu_sd_state_idle
| 0.00% native_irq_return_iret
| 0.00% schedule
| + 0.00% arch_cpu_idle_exit
| 0.00% __tick_nohz_idle_enter
| 0.00% irq_entries_start
| 0.00% sched_clock_idle_wakeup_event
| 0.00% reschedule_interrupt
| + 0.00% apic_timer_interrupt
| + 0.20% start_secondary
| + 0.00% x86_64_start_kernel
| + 53.51% 0.00% swapper [kernel.kallsyms] [k] start_secondary
| + 53.02% 0.08% swapper [kernel.kallsyms] [k] call_cpuidle
| - 52.94% 0.02% swapper [kernel.kallsyms] [k] cpuidle_enter
| - 52.92% cpuidle_enter
| + 31.81% cpuidle_enter_state
| + 20.01% ret_from_intr
| + 0.51% apic_timer_interrupt
| 0.28% native_irq_return_iret
| + 0.09% reschedule_interrupt
| 0.05% irq_entries_start
| 0.05% do_IRQ
| 0.05% common_interrupt
| 0.02% sched_idle_set_state
| 0.01% acpi_idle_enter
| 0.01% ktime_get
| 0.01% restore_regs_and_iret
| 0.01% restore_c_regs_and_iret
| + 0.01% call_function_single_interrupt
| 0.00% native_iret
| + 0.00% call_function_interrupt
| 0.00% smp_apic_timer_interrupt
| 0.00% smp_reschedule_interrupt
| 0.00% smp_call_function_single_interrupt
| + 0.02% start_secondary
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