On 11/3/15, 9:59 AM, "Polehn, Mike A" <mike.a.polehn at intel.com> wrote:
>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 */ Looks reasonable I assume the n_bytes does not include FCS as is not the case with the NIC counters. Also I decided to avoid using double?s in my code and just used 64bit registers and integer math :-) > >-----Original Message----- >From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Wiles, Keith >Sent: Tuesday, November 3, 2015 6:33 AM >To: Van Haaren, Harry; ???; dev at 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 at intel.com> wrote: > >>Hi Keith, >> >>> From: dev [mailto:dev-bounces at 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 > > > > > Regards, Keith
