> The preferred governor with the intel_pstate driver is powersave. Do you have some references/proof for that? This is contrary to what kernel developers say, see comment 1.
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to sysvinit in Ubuntu. 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: Fix Released 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 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1579278/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
