On Fri, Jun 24, 2011 at 02:04:41PM -0500, Shawn Bohrer wrote: > Running 3.0.0-rc4+ I noticed I'm seeing the following on an idle Dell > r610 system: > > Cpu0 : 0.0%us, 0.0%sy, 0.0%ni, 64.3%id, 0.0%wa, 35.7%hi, 0.0%si, 0.0%st > Cpu1 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu2 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu3 : 0.0%us, 0.0%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.3%hi, 0.3%si, 0.0%st > Cpu4 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu5 : 0.0%us, 0.0%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.3%hi, 0.3%si, 0.0%st > Cpu6 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu7 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st > Cpu8 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu9 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu10 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu11 : 0.0%us, 0.0%sy, 0.0%ni,100.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st > Cpu12 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > Cpu13 : 0.0%us, 0.0%sy, 0.0%ni, 99.3%id, 0.0%wa, 0.3%hi, 0.3%si, 0.0%st > Cpu14 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st > Cpu15 : 0.0%us, 0.0%sy, 0.0%ni, 99.7%id, 0.0%wa, 0.3%hi, 0.0%si, 0.0%st > > Watching /proc/interrupts it looks like most of the interrupts on CPU0 > are on IRQ 0 from "IO-APIC-edge timer". > > perf top -C 0 shows: > > --------------------------------------------------------------------- > PerfTop: 1024 irqs/sec kernel:100.0% exact: 0.0% [1000Hz cycles], (all, CPU: 0) > --------------------------------------------------------------------- > > samples pcnt function DSO > _______ _____ ___________________________________ _______ > > 11648.00 83.6% default_send_IPI_mask_sequence_phys vmlinux > 1548.00 11.1% _raw_spin_lock_irqsave vmlinux > 530.00 3.8% intel_idle vmlinux > 36.00 0.3% hpet_legacy_next_event vmlinux > 28.00 0.2% tick_handle_oneshot_broadcast vmlinux > 20.00 0.1% find_next_bit vmlinux > 16.00 0.1% find_busiest_group vmlinux > 15.00 0.1% _raw_spin_unlock_irqrestore vmlinux > 13.00 0.1% cpuidle_idle_call vmlinux > 10.00 0.1% _raw_spin_lock vmlinux > 9.00 0.1% tick_broadcast_oneshot_control vmlinux > 8.00 0.1% notifier_call_chain vmlinux > 7.00 0.1% leave_mm vmlinux > > For some reason 'perf record -C 0 -g sleep 5' doesn't record anything, > but here is the top functions from a 'perf record -a -g sleep 5': > > # Events: 77K cycles > # > # Overhead Command Shared Object Symbol > # ........ ............... .................. ................................... > # > 80.22% swapper [kernel.kallsyms] [k] _raw_spin_lock_irqsave > | > --- _raw_spin_lock_irqsave > | > |--89.92%-- clockevents_notify > | intel_idle > | cpuidle_idle_call > | cpu_idle > | | > | |--98.67%-- start_secondary > | | > | --1.33%-- rest_init > | start_kernel > | x86_64_start_reservations > | x86_64_start_kernel > | > |--10.03%-- tick_broadcast_oneshot_control > | tick_notify > | notifier_call_chain > | raw_notifier_call_chain > | clockevents_notify > | intel_idle > | cpuidle_idle_call > | cpu_idle > | | > | |--99.97%-- start_secondary > | --0.03%-- [...] > --0.05%-- [...] > > 9.32% swapper [kernel.kallsyms] [k] default_send_IPI_mask_sequence_phys > | > --- default_send_IPI_mask_sequence_phys > physflat_send_IPI_mask > lapic_timer_broadcast > tick_do_broadcast > tick_handle_oneshot_broadcast > timer_interrupt > handle_irq_event_percpu > handle_irq_event > handle_edge_irq > handle_irq > do_IRQ > common_interrupt > | > |--99.91%-- cpuidle_idle_call > | cpu_idle > | rest_init > | start_kernel > | x86_64_start_reservations > | x86_64_start_kernel > --0.09%-- [...] > > 5.83% swapper [kernel.kallsyms] [k] intel_idle > | > --- intel_idle > | > |--99.67%-- cpuidle_idle_call > | cpu_idle > | | > | |--94.19%-- start_secondary > | | > | --5.81%-- rest_init > | start_kernel > | x86_64_start_reservations > | x86_64_start_kernel > --0.33%-- [...] > > I'm not sure what other information would be useful here. Please let > me know if you need anything else. The above info was taken with CONFIG_INTEL_IDLE=y, unsetting this config option makes the problem go away. Here is some more info about the system that may be relevant. $ cat /proc/cpuinfo | grep model | sort -u model: 26 model name: Intel(R) Xeon(R) CPU X5570 @ 2.93GHz $ dmesg | grep command Kernel command line: ro root=/dev/sda2 selinux=0 audit=0 processor.max_cstate=0 crashkernel=128M $ sudo omreport chassis biossetup BIOS Setup General Boot Sequence : Hard drive C: Num Lock : On User Accessible USB Ports : All Ports On Processor Virtualization Technology : Disabled Processor Logical Processor (HyperThreading) : Enabled AC Power Recovery Mode : On Embedded SATA Controller : Off SATA Port 0 : Off Dual NIC (1/2) : Enabled with 1st NIC PXE and 2nd NIC None Dual NIC (3/4) : Enabled with 1st NIC None and 2nd NIC None TPM Security : Off Internal USB Port : Enabled OS Watchdog Timer : Disabled Processor Core Based Turbo Mode : Enabled Node Interleaving : Disabled Processor Execute Disable : Enabled Processor CMP : 4 Boot Mode : BIOS Processor C State Control : Enabled Processor C1-E : Disabled Serial Communications Serial Communications : On without Console Redirection Console Redirection After Boot : Enabled External Serial Connector : Serial Device1 Console Redirection Failsafe BAUD Rate : 115200 Serial Address Select : Serial Device1=COM1, Serial Device2=COM2 -- Shawn --------------------------------------------------------------- This email, along with any attachments, is confidential. 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