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

Hemant Agrawal hemant.agrawal at nxp.com
Tue Aug 23 12:01:55 CEST 2016


> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Jerin Jacob
> Sent: Thursday, August 18, 2016 5:22 PM
> To: dev at dpdk.org
> Cc: thomas.monjalon at 6wind.com; jianbo.liu at linaro.org;
> viktorin at rehivetech.com; Jerin Jacob <jerin.jacob at caviumnetworks.com>
> Subject: [dpdk-dev] [PATCH] eal/armv8: high-resolution cycle counter
> 
> 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>


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