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Node.js is a popular platform to write server-side applications. Profiling Node.js based application is supported out of the box with Polar Signals Cloud.

To see function names for Javascript code the --perf-basic-prof-only-functions flag must be passed to the node command. For better quality we also recommend to pass the --interpreted-frames-native-stack flag.

For example the full command might look like this:

node --perf-basic-prof-only-functions --interpreted-frames-native-stack main.js


Below are some situations and how to troubleshoot them. If you've tried these and still haven't been able to resolve the issue, please contact support.

Only functions broken

For a long time --perf-basic-prof-only-functions was broken and resulted in incomplete data, ensure you are using a new enough version that fixes it.


The fix is not being backported for v16. Use --perf-basic-prof instead.


Fixed in v18.19.0 (specifically commit 5f852cc) make sure to use v18.19.0 or newer of the v18 release series.


Fixed in 20.10.0 (specifically commit e63aef9) make sure to use v20.10.0 or newer of the v20 release series.


Fixed in v21.1.0 (specifically commit f4da308) make sure to use v21.1.0 or newer of the v21 release series.

All I can see is memory addresses

First make sure the node process is started with the --perf-basic-prof-only-functions and --interpreted-frames-native-stack flags. Then check that the process is successfully writing a perfmap. By default, perfmaps are written to /tmp/perf-<PID>.map.

On Kubernetes for example this can be checked with:

kubectl exec --namespace <namespace-name> <pod-name> -- ls -la /tmp

For example:

$ kubectl exec -n default nodejs-demo -- ls -la /tmp
total 144
drwxrwxrwt 1 root root 4096 Jul 12 08:59 .
drwxr-xr-x 1 root root 4096 Jul 12 08:59 ..
-rw-r--r-- 1 root root 131811 Jul 12 08:59
drwxr-xr-x 3 root root 4096 Jul 4 17:33 v8-compile-cache-0

In this example the file we're looking for is the For you it should be called something similar.