Values published in the stats segment: vpp# show stat segment <snip> /sys/vector_rate ScalarPtr 0 # zero vector rate, idle system /sys/vector_rate_per_worker CMainPtr 0 # single core... <snip>
Take a look at src/vpp/stats/stat_segment.c:do_stat_segment_updates(...) for more detail. -----Original Message----- From: [email protected] <[email protected]> On Behalf Of Elias Rudberg Sent: Wednesday, November 11, 2020 5:08 AM To: [email protected]; [email protected]; [email protected] Subject: Re: [vpp-dev] VPP load estimation Hi Ben, > Yes, it is the main way to quickly assess VPP load, see > https://fd.io/docs/vpp/master/troubleshooting/cpuusage.html#vpp-cpu-lo > ad My very crude rule-of-thumb looks like this (but your mileage may > vary): > - between 0 and 50: VPP is not working too hard > - between 50 and 100: VPP is starting to be pushed hard > - above 100: you'll probably experiment drops with bursts > - 250+: you're dropping traffic Is it possible to get this information using the python API instead of the vppctl "show runtime" command? In our case we have some monitoring tools that fetch statistics from VPP regularly, like several times each minute. So then we would like to do it in a way that does not cause performance problems. Is it a bad idea to use the vppctl "show runtime" command frequently (it causes a thread barrier I think) and if so, is there a better way of getting the corresponding information? I also have another question related to load estimation: we are using VPP for NAT44 and we are seeing a significant number (like 1000 per second) of congestion drops (meaning that a NAT thread wants to handoff packets to another thread but the handoff queue is full). Then we looked at the "show runtime" output and expected to see some large values for the vector rate there, but it just shows values like 7 and similar, far below 50, which by your rule of thumb should indicate that VPP is not working too hard. In this case, are there some other statistics we could look at to figure out what is happening? One theory is that there are some short bursts of more intense traffic causing our drops, that we do not see with "show runtime" because statistics there are smeared out over time. Are there some other statistics we could use to understand if that is the case, or better ways to investigate this kind of problem? Best regards, Elias
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