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Date: Tue, 4 Oct 2016 14:45:26 +0200
From: Jan Viktorin <viktorin@rehivetech.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
Cc: Jerin Jacob <jerin.jacob@caviumnetworks.com>, dev@dpdk.org,
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Subject: Re: [dpdk-dev] [PATCH] doc: arm64: document DPDK application
 profiling methods
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On Tue, 04 Oct 2016 14:40:47 +0200
Thomas Monjalon <thomas.monjalon@6wind.com> wrote:

> Thanks for providing a patch so quickly :)
> 
> 2016-10-04 16:10, Jerin Jacob:
> > +The PMU based scheme useful for high accuracy performance profiling.  
> 
> A verb is missing.
> 
> > +Find below the example steps to configure the PMU based cycle counter on an
> > +armv8 machine.
> > +
> > +.. code-block:: console
> > +
> > +    git clone https://github.com/jerinjacobk/armv8_pmu_cycle_counter_el0
> > +    cd armv8_pmu_cycle_counter_el0
> > +    make
> > +    sudo insmod pmu_el0_cycle_counter.ko
> > +    cd $DPDK_DIR
> > +    make config T=arm64-armv8a-linuxapp-gcc
> > +    echo "CONFIG_RTE_ARM_EAL_RDTSC_USE_PMU=y" >> build/.config
> > +    make  
> 
> What about the ARM 32 code that Jan is using?

Hi, I didn't have time for this yet. The basic description is here:

 lib/librte_eal/common/include/arch/arm/rte_cycles_32.h

In the Linux Kernel, it is used here:

 arch/arm/kernel/perf_event_v7.c (see registers c12, c13 and c14)

Regards
Jan

> 
> > +.. warning::
> > +
> > +    This method can not be used in production systems as this may alter PMU
> > +    state used by standard Linux user space tool like perf.  
> 
> More details please?
> 



-- 
   Jan Viktorin                  E-mail: Viktorin@RehiveTech.com
   System Architect              Web:    www.RehiveTech.com
   RehiveTech
   Brno, Czech Republic