Re: [dpdk-dev] How can I calculate/estimate pps(packet per seocond) and bps(bit per second) in DPDK pktg

["Polehn, Mike A" <mike.a.polehn@intel.com>]

I used the following code snip-it with the i40e device, with 1 second sample time had very high accuracy for IPv4 UDP packets:

#define FLOWD_PERF_PACKET_OVERHEAD 24  /* CRC + Preamble + SOF + Interpacket gap */
#define FLOWD_REF_NETWORK_SPEED   10e9

double Ave_Bytes_per_Packet, Data_Rate, Net_Rate;
uint64_t Bits;
uint64_t Bytes = pFlow->flow.n_bytes - pMatch_Prev->flow.n_bytes;
uint64_t Packets = pFlow->flow.n_packets - pMatch_Prev->flow.n_packets;
uint64_t Time_us = pFlow->flow.flow_time_us - pMatch_Prev->flow.flow_time_us;

if (Bytes == 0)
	Ave_Bytes_per_Packet = 0.0;
else
	Ave_Bytes_per_Packet = ((double)Bytes / (double)Packets) + 4.0;

Bits = (Bytes + (Packets*FLOWD_PERF_PACKET_OVERHEAD)) * 8;
if (Bits == 0)
	Data_Rate = 0.0;
else
	Data_Rate = (((double)Bits) / Time_us) * 1e6;

if (Data_Rate == 0.0)
	Net_Rate = 0.0;
else
	Net_Rate = Data_Rate / FLOWD_REF_NETWORK_SPEED;

For packet rate: double pk_rate = (((double)Packets)/ ((double)Time_us)) * 1e6;

To calculate elapsed time in DPDK app, used CPU counter (will not work if counter is being modified):

Initialization:
double flow_time_scale_us;
...
flow_time_scale_us = 1e6/rte_get_tsc_hz();

Elapsed time (uSec) example: 

elapse_us = (rte_rdtsc() - entry->tsc_first_packet) *
	flow_time_scale_us; /* calc total elapsed us */

-----Original Message-----
From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wiles, Keith
Sent: Tuesday, November 3, 2015 6:33 AM
To: Van Haaren, Harry; ???; dev@dpdk.org
Subject: Re: [dpdk-dev] How can I calculate/estimate pps(packet per seocond) and bps(bit per second) in DPDK pktg

On 11/3/15, 8:30 AM, "Van Haaren, Harry" <harry.van.haaren@intel.com> wrote:

>Hi Keith,
>
>> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Wiles, Keith
><snip>
>> Hmm, I just noticed I did not include the FCS bytes. Does the NIC 
>> include FCS bytes in the counters? Need to verify that one and if not then it becomes a bit more complex.
>
>The Intel NICs count packet sizes inclusive of CRC / FCS, from eg the ixgbe/82599 datasheet:
>"This register includes bytes received in a packet from the <Destination Address> field through the <CRC> field, inclusively."

Thanks I assumed I had known that at the time :-)
>
>-Harry
>


Regards,
Keith