4.2.4. Performance Tuning¶
Slow packet processing¶
Packet processing performance is not as high as expected.
Follow the advice provided in
fast-path.sh config -iwhen using the advanced configuration.
If running in a VM, check that the
qemuinstance handling your VM is pinned on specific cores. See CPU Pinning for VMs section for details.
Performance drop with Mellanox ConnectX-3 devices¶
Packet processing is slower than expected
On Dell and SuperMicro servers, PCI read buffer may be misconfigured for ConnectX-3/ConnectX-3-Pro NICs. Check the output of
setpci -s <NIC_PCI_address> 68.w. For instance:
# lspci | grep Mellanox 04:00.0 Ethernet controller: Mellanox Technologies MT27520 Family [ConnectX-3 Pro] # setpci -s 04:00.0 68.w 202e
Beware with the following command, it is known to cause spontaneous reboot on some systems.
If the value is below 0x5020 (here that’s the case), set it to 0x5020:
# setpci -s 04:00.0 68.w=5020