Re: [dpdk-dev] DPDK-Pktgen

["Wiles, Keith" <keith.wiles@intel.com>]

On 6/16/15, 4:18 PM, "Assaad, Sami (Sami)"
<sami.assaad@alcatel-lucent.com> wrote:

>Hello.
>
>I am using DPDK-Pktgen (Pktgen version 2.77 using DPDK-1.7.1).
>My NIC consists of two 10G ports.

Please try to use the latest version from here
http://dpdk.org/browse/apps/pktgen-dpdk/refs/

The one you are using is fairly old now.
>Now, my question is : How are the port MBits/s Rx/Tx calculated?

You could look at the code to find the answer on exactly how it calculates
the bit rate.

>
>Example: I am running the traffic generator with the following
>configuration:
>
>*         400 Byte Packet Sizes
>
>*         At Line Rate (i.e: 100%)
>
>*         Unidirectional (Tx only)
>
>The Pkts/s TX is 2985600. (Looks correct)
>But the MBits/s Tx is set to 2006 (per port Tx).

INTER_FRAME_GAP         = 12,
    PKT_PREAMBLE_SIZE       = 8,
    FCS_SIZE                = 4,

#define Million                 (uint64_t)(1000ULL * 1000ULL)

#define iBitsTotal(_x) \
    (((_x.ipackets * (INTER_FRAME_GAP + PKT_PREAMBLE_SIZE)) + _x.ibytes)
<< 3)
#define oBitsTotal(_x) \
    (((_x.opackets * (INTER_FRAME_GAP + PKT_PREAMBLE_SIZE)) + _x.obytes)
<< 3)

snprintf(buff, sizeof(buff), "%lu/%lu",
       iBitsTotal(info->rate_stats)/Million,
oBitsTotal(info->rate_stats)/Million);
        wr_scrn_printf(row++,  col, "%*s", COLUMN_WIDTH_1, buff);

I will let you do the math :-)

When I run the 2.9.1 code and DPDK 2.1 I get almost line rate for 400
bytes frames.
The values are calculated from the NIC counters. If the old is wrong then
update to the latest version is my only suggestion.

Regards,
++Keith



>
>How does DPDK-Pktgen calculate 2006 MBits/s Tx ?
>Is this a bug?
>
>Thanks in advance.
>
>Best Regards,
>Sami Assaad.
>