Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm using Mac OS X, I noticed 2 columns in Activity Monitor: Sent Msgs & Rcvd Msgs

I was wondering what is the meaning of them and what kind of messages are they, Are they network packets or something else? I noticed some of applications are continuously sending and receiving them should I be concerned?

share|improve this question
Please don't cross post questions. Your other question on Stack Overflow was migrated here and this just causes a mess. In the future, please post your question once and don't let people tell you to ask it elsewhere. A question can always be migrated. Thanks! – slhck May 10 '12 at 9:50
up vote 2 down vote accepted

Those numbers refer to Mach messages used to request and receive services from the system kernel. You'll have to grok Apple's kernel documentation to understand which kernel interfaces generate these messages and why. Unless you do low level system programming there is no reason for you to care about the message count numbers, which is why they aren't displayed by default.

share|improve this answer
Thank you for your answer. – Sam May 9 '12 at 13:07

These are messages sent between different running processes on your computer. It is normal for processes to send and receive messages.

It is not an indication of network traffic.

share|improve this answer
Thank you for your answer. – Sam May 9 '12 at 13:07

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.