• Using PMU on cortex-a9 CPU
    Folks, I am trying to run linux 'perf' on a new board with 2 ARM cortex-a9 CPUs. After compiling the kernel to include perf tool, i run 'perf stat true' and it returns valid stats. But when I run 'perf...
  • ARM v8 PMU Cycle counter
    All, When I am using the cycle counter in AArch64, I am not getting cycles properly. I have enabled read of pmccntr_el0 in user space using a small kernel module. I have sample code like: asm volatile...
  • STREX always clears the exclusive access tag
    Hello everybody, Section 18.8 Exclusive access of Cortex-A Series Programmer's Guide says the following: STREX can be considered as a conditional store. The store is performed only if the physical address...
  • Can we use PMU(Performance Measuring Unit) on Cortex A8 for calculating cycles on Simulator without hardware?
    ARMv7A family members will have PMU on the processor. Using this PMU, we can access cycle counts. Can we relay on this using the simulator?
  • PMU's cycles counter showing unstable values
    I'm trying to measure performance of my code by using pmu. Code placed in EL1. To test pmu I created simple loop of couple operations. I did it under spinlock with disabled interrupts to prevent any preemption...