From the sar manpage:


Percentage of memory needed for current workload in relation to the total amount of memory (RAM+swap). This number may be greater than 100% because the kernel usually overcommits memory.

Does this include data that had to be brought into the page cache during the given time period the entry covers?

1 Answer 1


Unlike other metrics (eg. CPU utilization) which are calculated over a time interval, the values displayed by "sar -r" (among them is %commit) are instantaneous values, based on values read from /proc/meminfo file. So %commit includes data that are in the page cache at the end of the given time period the entry covers.

  • 1
    This answer would get even better with a primary source, like a documentation or source code link
    – cat
    Aug 15, 2017 at 0:52

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