Re: [dpdk-dev] [PATCH 2/5] app/testpmd: print fractional part in CPU cycles

["Ananyev, Konstantin" <konstantin.ananyev@intel.com>]

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Dharmik Thakkar
> Sent: Wednesday, May 6, 2020 10:59 PM
> To: Lu, Wenzhuo <wenzhuo.lu@intel.com>; Wu, Jingjing <jingjing.wu@intel.com>; Iremonger, Bernard <bernard.iremonger@intel.com>
> Cc: dev@dpdk.org; nd@arm.com; Dharmik Thakkar <dharmik.thakkar@arm.com>
> Subject: [dpdk-dev] [PATCH 2/5] app/testpmd: print fractional part in CPU cycles
> 
> Change printing of CPU cycles/packet to include fractional part for
> accurateness.
> 
> Example:
> 
> Without patch:
> CPU cycles/packet=14
> (total cycles=4899533541 / total RX packets=343031966)
> 
> With patch:
> CPU cycles/packet=14.28
> (total cycles=4899533541 / total RX packets=343031966)
> 
> Signed-off-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Phil Yang <phil.yang@arm.com>
> ---
>  app/test-pmd/testpmd.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
> index 9a8cbbd6fc7c..9444a730a153 100644
> --- a/app/test-pmd/testpmd.c
> +++ b/app/test-pmd/testpmd.c
> @@ -1955,9 +1955,9 @@ fwd_stats_display(void)
>  #ifdef RTE_TEST_PMD_RECORD_CORE_CYCLES
>  #define CYC_PER_MHZ 1E6
>  	if (total_recv > 0)
> -		printf("\n  CPU cycles/packet=%u (total cycles="
> +		printf("\n  CPU cycles/packet=%.2f (total cycles="
>  		       "%"PRIu64" / total RX packets=%"PRIu64") at %lu MHz Clock\n",
> -		       (unsigned int)(fwd_cycles / total_recv),
> +		       (double)(fwd_cycles / (double)total_recv),

Probably safer long double - to avoid overflow. 

>  		       fwd_cycles, total_recv, (uint64_t)(rte_get_tsc_hz() / CYC_PER_MHZ));
>  #endif
>  }
> --
> 2.20.1