Dear Polehn, Mike A and DPDK experts. Thank you very much for your previous advice and answer.
I used the method you proposed. I dont't understand that the data rate includes preamble and inter-packet gap since the preamble and the inter-packet gap are not packet data. There are significant packet bursts in DPDK packet stream. I used average value of gps/pps history (128 history). It works well. Thank you very much. Sincerely Yours, Ick-Sung Choi. -----Original Message----- From: "Polehn, Mike A"<mike.a.pol...@intel.com> To: "???"<pnk003 at naver.com>; "Wiles, Keith"<keith.wiles at intel.com>; "Van Haaren, Harry"<harry.van.haaren at intel.com>; "dev at dpdk.org"<dev at dpdk.org>; Cc: Sent: 2015-11-04 (?) 23:21:54 Subject: RE: [dpdk-dev] How can I calculate/estimate pps(packet per seocond) and bps(bit per second) in DPDK pktg The change in tsc value from rte_rdtsc() needs to be multiplied by the scale to convert from clocks to get change in seconds. For example from below: elapse_us = (rte_rdtsc() - entry->tsc_first_packet) * flow_time_scale_us; The bit rate requires the number of bytes passed in the time period then adjusted by the overhead of the number of packets transferred in the time period. #define FLOWD_PERF_PACKET_OVERHEAD 24 /* CRC + Preamble + SOF + Interpacket gap */ Bits = (Bytes + (Packets*FLOWD_PERF_PACKET_OVERHEAD)) * 8; Data_Rate = (((double)Bits) / Time_us) * 1e6; Integer math is very tricky and often is not any faster than floating point math when using multiplies except on the very low performance processors. Mike From: ??? [mailto:pnk003 at naver.com] Sent: Tuesday, November 3, 2015 5:45 PM To: Polehn, Mike A; Wiles, Keith; 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 Dear Wiles, Keith , Van Haaren, Harry, Polehn, Mike A, Stephen Hemminger, Kyle Larose, and DPDK experts. I really appreciate for your precious answers and advices. I will find and study the corresponding codes and CRC checking. Last night, I tried to estimate bps and pps by using the following code. // rte_distributor_process() gets 64 mbufs packets at a time. // rte_distributor_process() gets packets from Intel? 82599ES 10 Gigabit Ethernet 2 port Controller (2 10gbE ports). int rte_distributor_process(struct rte_distributor *d, struct rte_mbuf **mbufs, unsigned num_mbufs) { uint64_t ticks_per_ms = rte_get_tsc_hz()/1000 ; uint64_t ticks_per_s = rte_get_tsc_hz() ; uint64_t ticks_per_s_div_8 = rte_get_tsc_hz()/8 ; uint64_t cur_tsc = 0, last_tsc = 0, sum_len, bps, pps ; cur_tsc = rte_rdtsc(); sum_len = 0 ; for (l=0; l < num_mbufs; l++ ) { sum_len += mbufs[l]->pkt_len ; } if ((cur_tsc - last_tsc)!=0) { bps = (sum_len * ticks_per_s_div_8 ) / (cur_tsc - last_tsc) ; pps = num_mbufs * ticks_per_s / (cur_tsc - last_tsc) ; } else bps = pps = 0 ; last_tsc = cur_tsc ; } I got max. bit per second = 6,835,440,833 for 20 Gbps 1500 bytes packet traffic, and got max. bit per second = 6,808,524,220 for 2 Gbps 1500 bytes packet traffic. I guess there can be packet burst, however the estimated value has too many errors. I will try the methods you proposed. Thank you very much. Sincerely Yours, Ick-Sung Choi. -----Original Message----- From: "Polehn, Mike A"<mike.a.pol...@intel.com> To: "Wiles, Keith"<keith.wiles at intel.com>; "Van Haaren, Harry"<harry.van.haaren at intel.com>; "???"<pnk003 at naver.com>; "dev at dpdk.org"<dev at dpdk.org>; Cc: Sent: 2015-11-04 (?) 00:59:34 Subject: RE: [dpdk-dev] How can I calculate/estimate pps(packet per seocond) and bps(bit per second) in DPDK pktg 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-boun...@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
