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

[최익성 <pnk003@naver.com>]

 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.polehn@intel.com> 
To: "Wiles, Keith"<keith.wiles@intel.com>; "Van Haaren, Harry"<harry.van.haaren@intel.com>; "???"<pnk003@naver.com>; "dev@dpdk.org"<dev@dpdk.org>; 
Cc: 
Sent: 2015-11-04 (수) 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-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