Hi Bruce,

We have been seeing in some cases that the DPDK forwarding performance is up to 
9% lower when DPDK is built as static with meson compared to a build with 
makefiles.

The same degradation can be reproduced with makefiles on older DPDK releases 
when building with EXTAR_CFLAGS set to "-fPIC", it can also be resolved in 
meson when passing "pic: false" to meson's static_library call (more tweaking 
needs to be done to prevent building shared libraries because this change 
breaks them).

I can reproduce this drop with the following cases:

  *   Baremetal / NIC: ConnectX-4 Lx / OS: RHEL7.4 / CPU: Intel(R) Xeon(R) Gold 
6154. Testpmd command:
testpmd -c 0x7ffc0000 -n 4 -w d8:00.1 -w d8:00.0 --socket-mem=2048,2048 -- 
--port-numa-config=0,1,1,1 --socket-num=1 --burst=64 --txd=512 --rxd=512 
--mbcache=512 --rxq=2 --txq=2 --nb-cores=1 --no-lsc-interrupt -i -a --rss-udp

  *   KVM guest with SR-IOV passthrough / OS: RHEL7.4 / NIC: ConnectX-5 / 
Host's CPU: Intel(R) Xeon(R) Gold 6154. Testpmd command:
testpmd --master-lcore=0 -c 0x1ffff -n 4 -w 
00:05.0,mprq_en=1,mprq_log_stride_num=6 --socket-mem=2048,0 -- 
--port-numa-config=0,0 --socket-num=0 --burst=64 --txd=1024 --rxd=1024 
--mbcache=512 --rxq=16 --txq=16 --nb-cores=8 --port-topology=chained 
--forward-mode=macswap --no-lsc-interrupt -i -a --rss-udp
  *   Baremetal / OS: Ubuntu 18.04 / NIC: ConnectX-5 / CPU: Intel(R) Xeon(R) 
CPU E5-2697A v4. Testpmd command:
testpmd -n 4  -w 0000:82:00.0,rxqs_min_mprq=8,mprq_en=1  -w 
0000:82:00.1,rxqs_min_mprq=8,mprq_en=1 -c 0xff80  -- --burst=64 --mbcache=512 
-i  --nb-cores=8  --rxq=8 --txq=8 --txd=1024 --rxd=1024 --rss-udp --auto-start
The packets being received and forwarded by testpmd are of IPv4/UDP type and 
64B size.

Should we disable PIC in static builds?

Regards,
Ali

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