Re: [dpdk-dev] Performance hit - NICs on different CPU sockets

[Take Ceara <dumitru.ceara@gmail.com>]

On Thu, Jun 16, 2016 at 5:29 PM, Wiles, Keith <keith.wiles@intel.com> wrote:

>
> Right now I do not know what the issue is with the system. Could be too many Rx/Tx ring pairs per port and limiting the memory in the NICs, which is why you get better performance when you have 8 core per port. I am not really seeing the whole picture and how DPDK is configured to help more. Sorry.

I doubt that there is a limitation wrt running 16 cores per port vs 8
cores per port as I've tried with two different machines connected
back to back each with one X710 port and 16 cores on each of them
running on that port. In that case our performance doubled as
expected.

>
> Maybe seeing the DPDK command line would help.

The command line I use with ports 01:00.3 and 81:00.3 is:
./warp17 -c 0xFFFFFFFFF3   -m 32768 -w 0000:81:00.3 -w 0000:01:00.3 --
--qmap 0.0x003FF003F0 --qmap 1.0x0FC00FFC00

Our own qmap args allow the user to control exactly how cores are
split between ports. In this case we end up with:

warp17> show port map
Port 0[socket: 0]:
   Core 4[socket:0] (Tx: 0, Rx: 0)
   Core 5[socket:0] (Tx: 1, Rx: 1)
   Core 6[socket:0] (Tx: 2, Rx: 2)
   Core 7[socket:0] (Tx: 3, Rx: 3)
   Core 8[socket:0] (Tx: 4, Rx: 4)
   Core 9[socket:0] (Tx: 5, Rx: 5)
   Core 20[socket:0] (Tx: 6, Rx: 6)
   Core 21[socket:0] (Tx: 7, Rx: 7)
   Core 22[socket:0] (Tx: 8, Rx: 8)
   Core 23[socket:0] (Tx: 9, Rx: 9)
   Core 24[socket:0] (Tx: 10, Rx: 10)
   Core 25[socket:0] (Tx: 11, Rx: 11)
   Core 26[socket:0] (Tx: 12, Rx: 12)
   Core 27[socket:0] (Tx: 13, Rx: 13)
   Core 28[socket:0] (Tx: 14, Rx: 14)
   Core 29[socket:0] (Tx: 15, Rx: 15)

Port 1[socket: 1]:
   Core 10[socket:1] (Tx: 0, Rx: 0)
   Core 11[socket:1] (Tx: 1, Rx: 1)
   Core 12[socket:1] (Tx: 2, Rx: 2)
   Core 13[socket:1] (Tx: 3, Rx: 3)
   Core 14[socket:1] (Tx: 4, Rx: 4)
   Core 15[socket:1] (Tx: 5, Rx: 5)
   Core 16[socket:1] (Tx: 6, Rx: 6)
   Core 17[socket:1] (Tx: 7, Rx: 7)
   Core 18[socket:1] (Tx: 8, Rx: 8)
   Core 19[socket:1] (Tx: 9, Rx: 9)
   Core 30[socket:1] (Tx: 10, Rx: 10)
   Core 31[socket:1] (Tx: 11, Rx: 11)
   Core 32[socket:1] (Tx: 12, Rx: 12)
   Core 33[socket:1] (Tx: 13, Rx: 13)
   Core 34[socket:1] (Tx: 14, Rx: 14)
   Core 35[socket:1] (Tx: 15, Rx: 15)

Just for reference, the cpu_layout script shows:
$ $RTE_SDK/tools/cpu_layout.py
============================================================
Core and Socket Information (as reported by '/proc/cpuinfo')
============================================================

cores =  [0, 1, 2, 3, 4, 8, 9, 10, 11, 12]
sockets =  [0, 1]

        Socket 0        Socket 1
        --------        --------
Core 0  [0, 20]         [10, 30]
Core 1  [1, 21]         [11, 31]
Core 2  [2, 22]         [12, 32]
Core 3  [3, 23]         [13, 33]
Core 4  [4, 24]         [14, 34]
Core 8  [5, 25]         [15, 35]
Core 9  [6, 26]         [16, 36]
Core 10 [7, 27]         [17, 37]
Core 11 [8, 28]         [18, 38]
Core 12 [9, 29]         [19, 39]

I know it might be complicated to gigure out exactly what's happening
in our setup with our own code so please let me know if you need
additional information.

I appreciate the help!

Thanks,
Dumitru