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Message #182852
[Bug 1579278] Re: Consider changing default CPU frequency scaling governor back to "performance" (Ubuntu Server)
In yakkety I'll add an ondemand.service to systemd, as
/etc/init.d/ondemand fell out of the standard installation (as
"initscripts" is now -- thankfully -- gone). I'll keep the xenial task
in case someone is interested in SRUing this.
** Changed in: sysvinit (Ubuntu)
Status: New => Invalid
** Changed in: sysvinit (Ubuntu Xenial)
Status: New => Triaged
** Also affects: systemd (Ubuntu)
Importance: Undecided
Status: New
** Changed in: systemd (Ubuntu Xenial)
Status: New => Invalid
** Changed in: systemd (Ubuntu)
Status: New => In Progress
** Changed in: systemd (Ubuntu Xenial)
Assignee: (unassigned) => Martin Pitt (pitti)
** Changed in: systemd (Ubuntu)
Importance: Undecided => Medium
** Changed in: sysvinit (Ubuntu Xenial)
Importance: Undecided => Medium
** Summary changed:
- Consider changing default CPU frequency scaling governor back to "performance" (Ubuntu Server)
+ Keep powersave CPU frequency scaling governor for CPUs that support intel_pstate
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https://bugs.launchpad.net/bugs/1579278
Title:
Keep powersave CPU frequency scaling governor for CPUs that support
intel_pstate
Status in linux package in Ubuntu:
Invalid
Status in systemd package in Ubuntu:
In Progress
Status in sysvinit package in Ubuntu:
Invalid
Status in linux source package in Xenial:
Invalid
Status in systemd source package in Xenial:
Invalid
Status in sysvinit source package in Xenial:
Triaged
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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References
