How to use Timer broadcast on Multi-Processor system with linux 3.10?

Posted by kevin.ji on Super User See other posts from Super User or by kevin.ji
Published on 2014-05-31T06:32:28Z Indexed on 2014/05/31 9:34 UTC
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Filed under:

linux

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arm

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timer

Hardware: ARM Cortex-A9 * 2

Software: linux-3.10.0

The platform has 2 cores of arm cortex-a9. Item CONFIG_LOCAL_TIMERS is not set in linux menuconfig. I want to use only one hardware timer to supply tick for all cpu.

Interrupts looks like:

          CPU0       CPU1       
 57:       6697          0       GIC  timer
 81:        213          0       GIC  uart-pl011
103:          0          0       GIC  gmac0
104:          0          0       GIC  gmac1
IPI0:          0          1  CPU wakeup interrupts
IPI1:          0          0  Timer broadcast interrupts
IPI2:        967        866  Rescheduling interrupts
IPI3:          0          0  Function call interrupts
IPI4:          1          2  Single function call interrupts
IPI5:          0          0  CPU stop interrupts
IPI6:          0          0  CPU backtrace
Err:          0

Timer broadcast interrupts counter does not add. And it looks like that cpu1 does not work at all.But this method works well with linux-3.4, and the interrupt info looks as below in linux-3.4:

# cat /proc/interrupts

           CPU0       CPU1       
 57:       8596          0       GIC  timer
 81:         91          0       GIC  uart-pl011
103:          0          0       GIC  gmac0
104:          0          0       GIC  gmac1
IPI0:          0       8560  Timer broadcast interrupts
IPI1:        884       1020  Rescheduling interrupts
IPI2:          0          0  Function call interrupts
IPI3:          0          6  Single function call interrupts
IPI4:          0          0  CPU stop interrupts
IPI5:          0          0  CPU backtrace
Err:          0

The count of Timer broadcast interrupts is adding. And all of cpus work well. I don't know why. Any answer is welcome. :)

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