Skip to content

lib,src: remove cpu profiler idle notifier

Rodrigo Muino Tomonari requested to merge github/fork/bnoordhuis/fix19009 into master

I added it in commit 57231d52 ("src: notify V8 profiler when we're idle") from October 2013 as a stop-gap measure to measure CPU time rather than wall clock time, otherwise processes that spend a lot of time sleeping in system calls give a false impression of being very busy.

That fix is not without drawbacks because the idle flag is set before libuv makes I/O callbacks and cleared again after. I/O callbacks can result into calls into JS code and executing JS code is as non-idle as you can get.

In commit 96ffcb9a ("src: reduce cpu profiler overhead") from January 2015, I made Node.js block off the SIGPROF signal that V8's CPU profiler uses before Node.js goes to sleep. The goal of that commit is to reduce the overhead from EINTR system call wakeups but it also has the pleasant side effect of fixing what the idle notifier tried to fix.

This commit removes the idle notifier and turns the JS process object methods into no-ops.

Fixes: https://github.com/nodejs/node/issues/19009 Refs: https://github.com/nodejs/node/pull/33138

Merge request reports