On 06/02/2013 07:53 PM, Thomas Renninger wrote: > On Wednesday, May 29, 2013 05:15:29 PM Daniel Lezcano wrote: >> On 05/29/2013 03:50 PM, Thomas Renninger wrote: >>> On Wednesday, May 29, 2013 03:38:59 PM Thomas Renninger wrote: >>>> Hi Rafael, >>>> >>>> it would be great if you could queue these up. >>> >>> While trying the disable interface with a recent kernel I found >>> a sever issue: >>> >>> One core seem to fire interrupts at a high rate. >>> intel_idle driver does not even enter C1, but only enters the POLL dummy >>> sleep state. >>> >>> perf top shows that only intel_idle is involved: >>> 90.00 70.9% intel_idle [kernel.kallsyms] >>> 16.00 12.6% _raw_spin_lock_irqsave [kernel.kallsyms] >>> >>> and that quite some (local) interrupts are happening: >>> PerfTop: 1016 irqs/sec >>> >>> cpupower monitor -m Mperf,Idle_Stats >>> >>> shows: >>> |Mperf || Idle_Stats >>> >>> PKG |CORE|CPU | C0 | Cx | Freq || POLL | C1-N | C1E- | C3-N | C6-N >>> >>> 1| 0| 0| 99.89| 0.11| 3065|| 99.81| 0.00| 0.00| 0.00| >>> 0.00 >>> >>> on the affected core and expected idleness: >>> |Mperf || Idle_Stats >>> >>> PKG |CORE|CPU | C0 | Cx | Freq || POLL | C1-N | C1E- | C3-N | C6-N >>> >>> 0| 3| 15| 0.04| 99.96| 1595|| 0.00| 0.00| 0.00| 0.00| >>> 99.99 >>> >>> on the other other cores. >>> I have seen this on a 3.10.0-rc2 kernel on a bigger server machine, but >>> with a 3.9.x kernel on a smaller desktop machine as well. >>> >>> Is this known already? >>> Any candidates I could try to revert? >> >> I was not able to reproduce it. > Did you try on a recent Intel processor machine? > Both machines I tried had rather recent Intel cpus. The more recent processor I have is an i7-3520M. >> Can you give the output of /proc/interrupts when that happens ? > > cat /proc/interrupts >/tmp/irqs;sleep 1;cat /proc/interrupts >>/tmp/irqs > uname -r > 3.10.0-rc2-3.g17364b5-default > > I also tried the latest: > 3.10.0-rc3-119-ga93cb29-1-vanilla > without any SUSE patches and it still shows the issue. > > Find also attached /proc/cpuinfo and /proc/config.gz AFAICT, there are a lot of local timer and CAL interrupts. Did you gather the infos after booting and disabling the state ? Or was your system running already running ? The poll state is rarely used in the system, if I am correct, it should be used when there a timer should expire within 5us (in the menu governor). Perhaps, there is a problem with a timer ? -- <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | <http://twitter.com/#!/linaroorg> Twitter | <http://www.linaro.org/linaro-blog/> Blog
