logd using high CPU on a Mac: finding the app that is logging too much
logd stores every log message on a Mac. When it is busy, an app is logging far too much. It used 1.4% CPU on our Mac. How to find the chatty process.
What is logd?
logd is macOS's logging service. Every log message from every app and system process goes through it into the unified log. It lives at /usr/libexec/logd and runs as root. On our Mac it used 1.4% CPU and 9 MB.
How do I find what is logging so much?
log stream --style compact | head -200Watch for a few seconds. One process repeating the same message many times a second is the cause. Stop the stream with Control C. Quitting or updating that app fixes logd.
Does all this logging fill my disk?
The unified log is capped and cleans up after itself, but apps that write their own log files do not. See system logs taking up space and app logs taking up space.
Can I quit logd?
Do not. It restarts, and while it is down messages are lost, including the ones you would need to diagnose a problem.
See it live
Free Mac's System tab ranks every process by processor use and energy impact, once a second, and marks the ones macOS will not let you quit as protected. See also spindump.
Common questions
What is logd on a Mac?
The macOS service that records log messages from every app and process into the unified log.
Why is logd using high CPU?
An app or process is logging a huge number of messages. log stream shows which.
Can I disable logd?
No. It restarts, and you lose the messages you would need to find the problem.