CPU Load/Usage
There are various commands and tools that can help users see FD.io VPP CPU and memory usage at runtime.
Linux top/htop
The Linux top and htop are decent tools to look at FD.io VPP cpu and memory usage, but they will only show preallocated memory and total CPU usage. These commands can be useful to show which cores VPP is running on.
This is an example of VPP instance that is running on cores 8 and 9. For this output type top and then type 1 when the tool starts.
$ top
top - 11:04:04 up 35 days, 3:16, 5 users, load average: 2.33, 2.23, 2.16
Tasks: 435 total, 2 running, 432 sleeping, 1 stopped, 0 zombie
%Cpu0 : 1.0 us, 0.7 sy, 0.0 ni, 98.0 id, 0.0 wa, 0.0 hi, 0.3 si, 0.0 st
%Cpu1 : 2.0 us, 0.3 sy, 0.0 ni, 97.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu2 : 0.7 us, 1.0 sy, 0.0 ni, 98.3 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu3 : 1.7 us, 0.7 sy, 0.0 ni, 97.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu4 : 2.0 us, 0.7 sy, 0.0 ni, 97.4 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu5 : 3.0 us, 0.3 sy, 0.0 ni, 96.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu6 : 2.3 us, 0.7 sy, 0.0 ni, 97.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu7 : 2.6 us, 0.3 sy, 0.0 ni, 97.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu8 : 96.0 us, 0.3 sy, 0.0 ni, 3.6 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu9 :100.0 us, 0.0 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
%Cpu10 : 1.0 us, 0.3 sy, 0.0 ni, 98.7 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
....
VPP Memory Usage
For details on VPP memory usage you can use the show memory command
This is the example VPP memory usage on 2 cores.
# vppctl show memory verbose
Thread 0 vpp_main
22043 objects, 17878k of 20826k used, 2426k free, 2396k reclaimed, 346k overhead, 1048572k capacity
alloc. from small object cache: 22875 hits 39973 attempts (57.23%) replacements 5143
alloc. from free-list: 44732 attempts, 26017 hits (58.16%), 528461 considered (per-attempt 11.81)
alloc. from vector-expand: 3430
allocs: 52324 2027.84 clocks/call
frees: 30280 594.38 clocks/call
Thread 1 vpp_wk_0
22043 objects, 17878k of 20826k used, 2427k free, 2396k reclaimed, 346k overhead, 1048572k capacity
alloc. from small object cache: 22881 hits 39984 attempts (57.23%) replacements 5148
alloc. from free-list: 44736 attempts, 26021 hits (58.17%), 528465 considered (per-attempt 11.81)
alloc. from vector-expand: 3430
allocs: 52335 2027.54 clocks/call
frees: 30291 594.36 clocks/call
VPP CPU Load
To find the VPP CPU load or how busy VPP is use the show runtime command.
With at least one interface in polling mode, the VPP CPU utilization is always 100%.
A good indicator of CPU load is "average vectors/node". A bigger number means VPP is more busy but also more efficient. The Maximum value is 255 (unless you change VLIB_FRAME_SIZE in code). It basically means how many packets are processed in batch.
If VPP is not loaded it will likely poll so fast that it will just get one or few packets from the rx queue. This is the case shown below on Thread 1. As load goes up vpp will have more work to do, so it will poll less frequently, and that will result in more packets waiting in rx queue. More packets will result in more efficient execution of the code so number of clock cycles / packet will go down. When "average vectors/node" goes up close to 255, you will likely start observing rx queue tail drops.
# vppctl show run
Thread 0 vpp_main (lcore 8)
Time 6152.9, average vectors/node 0.00, last 128 main loops 0.00 per node 0.00
vector rates in 0.0000e0, out 0.0000e0, drop 0.0000e0, punt 0.0000e0
Name State Calls Vectors Suspends Clocks Vectors/Call
acl-plugin-fa-cleaner-process event wait 0 0 1 3.66e4 0.00
admin-up-down-process event wait 0 0 1 2.54e3 0.00
....
---------------
Thread 1 vpp_wk_0 (lcore 9)
Time 6152.9, average vectors/node 1.00, last 128 main loops 0.00 per node 0.00
vector rates in 1.3073e2, out 1.3073e2, drop 6.5009e-4, punt 0.0000e0
Name State Calls Vectors Suspends Clocks Vectors/Call
TenGigabitEthernet86/0/0-outpu active 804395 804395 0 6.17e2 1.00
TenGigabitEthernet86/0/0-tx active 804395 804395 0 7.29e2 1.00
arp-input active 2 2 0 3.82e4 1.00
dpdk-input polling 24239296364 804398 0 1.59e7 0.00
error-drop active 4 4 0 4.65e3 1.00
ethernet-input active 2 2 0 1.08e4 1.00
interface-output active 1 1 0 3.78e3 1.00
ip4-glean active 1 1 0 6.98e4 1.00
ip4-icmp-echo-request active 804394 804394 0 5.02e2 1.00
ip4-icmp-input active 804394 804394 0 4.63e2 1.00
ip4-input-no-checksum active 804394 804394 0 8.51e2 1.00
ip4-load-balance active 804394 804394 0 5.46e2 1.00
ip4-local active 804394 804394 0 5.79e2 1.00
ip4-lookup active 804394 804394 0 5.71e2 1.00
ip4-rewrite active 804393 804393 0 5.69e2 1.00
ip6-input active 2 2 0 5.72e3 1.00
ip6-not-enabled active 2 2 0 1.56e4 1.00
unix-epoll-input polling 835722 0 0 3.03e-3 0.00