[dpdk-dev] [PATCH] eal/armv8: high-resolution cycle counter

Thomas Monjalon thomas.monjalon at 6wind.com
Tue Oct 4 10:46:54 CEST 2016


> > Existing cntvct_el0 based rte_rdtsc() provides portable means to get wall clock
> > counter at user space. Typically it runs at <= 100MHz.
> > 
> > The alternative method to enable rte_rdtsc() for high resolution wall clock
> > counter is through armv8 PMU subsystem.
> > The PMU cycle counter runs at CPU frequency, However, access to PMU cycle
> > counter from user space is not enabled by default in the arm64 linux kernel.
> > It is possible to enable cycle counter at user space access by configuring the
> > PMU from the privileged mode (kernel space).
> > 
> > by default rte_rdtsc() implementation uses portable
> > cntvct_el0 scheme. Application can choose the PMU based implementation with
> > CONFIG_RTE_ARM_EAL_RDTSC_USE_PMU
> > 
> > Signed-off-by: Jerin Jacob <jerin.jacob at caviumnetworks.com>
> 
> Acked-by: Hemant Agrawal <hemant.agrawal at nxp.com>

Applied, thanks

Please do not forget documentation and upstreaming efforts.


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