activitymonitord consistently using 11% of CPU, is there a way of changing this?

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Level 1

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activitymonitord consistently using 11% of CPU, is there a way of changing this?

activitymonitord only showed up noticeably last week after I switched to 64 bit processing in an effort to get Webex web conferencing working.

I know I can turn Activity Monitory off, but it is useful to have on at times with recent instabilities in Safari (and of course I can't see if the activitymonitord process is active if I turn the Monitoring off).

Prior to this, Activity Monitory would use 6-7% CPU, which seemed high in of itself.

The related postings do not answer this issue.

Thanks for any ideas

MacBook, Mac OS X (10.6.7), 2 GHz Core 2 Duo, 3GB Ram

Posted on May 22, 2011 12:56 AM

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Answer 1

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R C-R

Level 6

17,782 points

May 22, 2011 1:45 AM in response to sahmsahm

Activity Monitor doesn't really run continuously; instead it samples activity at regular intervals. Everything you see it list is a 'snapshot' of one moment in time of things that are actually changing much more frequently. The more often it samples, the more timely its info is, but it must of necessity use more system resources to do that.

You have four choices for the sampling interval, available from the "View" menu:

The "Less often" choice uses the CPU the least, but it always will use substantial system resources when it runs.

There is more about this in the PERFORMANCE vs. ACCURACY section of the man page for Top.

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Answer 2

sahmsahm Author

Level 1

10 points

May 22, 2011 12:11 PM in response to R C-R

Thank you, that was good information. Dropping the sample frequency from 2 sec to 5 sec did cut the CPU usage down to 5%, although is clearly is less precise too.

I'm still unclear as to why "activitymonitord" suddenly appeared and is using twice the CPU that "Activity Monitor" used to, and how to change it back.

Will relaunching Safari in 32 bit mode do the trick?

Thanks

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Answer 3

R C-R

Level 6

17,782 points

May 22, 2011 3:18 PM in response to sahmsahm

I found an "Activitymonitord hogging CPU" discussion from 2009 that suggests the excessive usage might be related either to Drobo software or to running the 64 bit kernel on some MacBooks. You might try booting up with the 32 bit kernel (if that is what your MacBook uses by default) & seeing if that makes a difference.

Beyond that, while my Activity Monitor & activitymonitord numbers are lower than yours, I do notice that as I increase the sample frequency, they begin to use substantial amounts of CPU time. Some samples:

@ 5 sec: Activity Monitor -- 0.5%, activitymonitord -- 0.8%

@ 1 sec: Activity Monitor -- 2.4%, activitymonitord -- 4%

@ 0.5 sec: Activity Monitor -- 4.6%, activitymonitord -- 7.9%

I'm not sure, but I think activitymonitord is the daemon that is responsible for setting the timing for the samples & doing the "heavy lifting" of gathering the info from all processes (since it runs as root) & Activity Monitor is basically the process that displays the info in the GUI. Neither process probably uses anywhere near as much CPU time as is indicated except when doing a sample.

 2008 24"/3.06 GHz iMac, Mac OS X (10.6.7)

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