Resource usage (% CPU) for given command on OS X

Question

The time -v command outputs % CPU utilization for a given command on Linux. How do I do this on OS X? The Linux/OS X difference is illustrated here. I would like to measure multi-core utilization across the total execution period of a short-running program, so top probably wouldn't work, as it measures/averages at particular points in time.

Answer 1

You man install the sysstat package and use the sar command.(https://tipstricks.itmatrix.eu/installing-sar-monitoring-tools/)

CPU Usage of ALL CPUs (sar -u)

This gives the cumulative real-time CPU usage of all CPUs. “1 3″ reports for every 1 seconds a total of 3 times. Most likely you’ll focus on the last field “%idle” to see the cpu load.

$ sar -u 1 3
 Linux 2.6.18-194.el5PAE (dev-db)        03/26/2011      _i686_  (8 CPU)

  01:27:32 PM       CPU     %user     %nice   %system   %iowait       %steal     %idle
  01:27:33 PM       all      0.00      0.00      0.00      0.00      0.00    100.00
  01:27:34 PM       all      0.25      0.00      0.25      0.00      0.00     99.50
  01:27:35 PM       all      0.75      0.00      0.25      0.00      0.00     99.00
  Average:          all      0.33      0.00      0.17      0.00      0.00       99.50

Following are few variations:

sar -u Displays CPU usage for the current day that was collected until that point.
sar -u 1 3 Displays real time CPU usage every 1 second for 3 times.
sar -u ALL Same as “sar -u” but displays additional fields.
sar -u ALL 1 3 Same as “sar -u 1 3″ but displays additional fields.
sar -u -f /var/log/sa/sa10 Displays CPU usage for the 10day of the month from the sa10 file.

CPU Usage of Individual CPU or Core (sar -P)

If you have 4 Cores on the machine and would like to see what the individual cores are doing, do the following.

“-P ALL” indicates that it should displays statistics for ALL the individual Cores.

In the following example under “CPU” column 0, 1, 2, and 3 indicates the corresponding CPU core numbers.

  $ sar -P ALL 1 1
  Linux 2.6.18-194.el5PAE (dev-db)        03/26/2011      _i686_  (8 CPU)

  01:34:12 PM       CPU     %user     %nice   %system   %iowait    %steal     %idle
  01:34:13 PM       all     11.69      0.00      4.71      0.69      0.00     82.90
  01:34:13 PM         0     35.00      0.00      6.00      0.00      0.00     59.00
  01:34:13 PM         1     22.00      0.00      5.00      0.00      0.00     73.00
  01:34:13 PM         2      3.00      0.00      1.00      0.00      0.00     96.00
  01:34:13 PM         3      0.00      0.00      0.00      0.00      0.00    100.00

“-P 1″ indicates that it should displays statistics only for the 2nd Core. (Note that Core number starts from 0).

  $ sar -P 1 1 1
  Linux 2.6.18-194.el5PAE (dev-db)        03/26/2011      _i686_  (8 CPU)

  01:36:25 PM       CPU     %user     %nice   %system   %iowait    %steal     %idle
 01:36:26 PM         1      8.08      0.00      2.02      1.01      0.00     88.89

Following are few variations:

sar -P ALL Displays CPU usage broken down by all cores for the current day.
sar -P ALL 1 3 Displays real time CPU usage for ALL cores every 1 second for 3 times (broken down by all cores).
sar -P 1 Displays CPU usage for core number 1 for the current day.
sar -P 1 1 3 Displays real time CPU usage for core number 1, every 1 second for 3 times.
sar -P ALL -f /var/log/sa/sa10 Displays CPU usage broken down by all cores for the 10day day of the month from sa10 file.

Answer 2

Seems like there is no real alternative to the gnu time command. So, in the end I installed just that. On OS X gnu-time can be installed with homebrew: brew install gnu-time. Thereafter CPU utilization for a specific command can be measured using gtime <command>. A test shows that my program is indeed running concurrently: 1.73user 0.13system 0:01.61elapsed 115%CPU.