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

[Dharmik Thakkar]

Hi Konstantin,

> On May 7, 2020, at 4:50 AM, Ananyev, Konstantin <konstantin.ananyev at intel.com> wrote:
> 
> 
> 
>> -----Original Message-----
>> From: dev <dev-bounces at dpdk.org> On Behalf Of Dharmik Thakkar
>> Sent: Wednesday, May 6, 2020 10:59 PM
>> To: Lu, Wenzhuo <wenzhuo.lu at intel.com>; Wu, Jingjing <jingjing.wu at intel.com>; Iremonger, Bernard <bernard.iremonger at intel.com>
>> Cc: dev at dpdk.org; nd at arm.com; Dharmik Thakkar <dharmik.thakkar at 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 at arm.com>
>> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli at arm.com>
>> Reviewed-by: Phil Yang <phil.yang at 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. 

Is it possible for a ‘double' to be less than 8 bytes?

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