X-Git-Url: http://git.droids-corp.org/?a=blobdiff_plain;f=doc%2Fguides%2Fprog_guide%2Fprofile_app.rst;h=e5d0e9079e1117729179b17cce4b081f2743b24a;hb=b762221ac24f;hp=a36ebef4db999ef96be1b3274525c882e6ee08c2;hpb=d629b7b5fe812f0040b83d27d2ada33b003aa918;p=dpdk.git diff --git a/doc/guides/prog_guide/profile_app.rst b/doc/guides/prog_guide/profile_app.rst index a36ebef4db..e5d0e9079e 100644 --- a/doc/guides/prog_guide/profile_app.rst +++ b/doc/guides/prog_guide/profile_app.rst @@ -57,11 +57,16 @@ For more derails refer to the `ARM64 specific PMU events enumeration `_. -High-resolution cycle counter -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +Low-resolution generic counter +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The default ``cntvct_el0`` based ``rte_rdtsc()`` provides a portable means to -get a wall clock counter in user space. Typically it runs at <= 100MHz. +get a wall clock counter in user space. Typically it runs at a lower clock frequency than the CPU clock frequency. +Cycles counted using this method should be scaled to CPU clock frequency. + + +High-resolution cycle counter +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ The alternative method to enable ``rte_rdtsc()`` for a high resolution wall clock counter is through the ARMv8 PMU subsystem. The PMU cycle counter runs