Peak Memory Usage

__1. Checking Peak Memory Usage

• How to : /usr/bin/time -v command
  • Maximum resident set size(Maximum RSS) : Peak Memory Usage
  • https://stackoverflow.com/questions/774556/peak-memory-usage-of-a-linux-unix-process/774601#774601
• Resident set size(RSS)
  • “resident set size (RSS) is the portion of memory occupied by a process that is held in main memory (RAM)”
  • https://en.wikipedia.org/wiki/Resident_set_size
  • https://stackoverflow.com/a/60779604
• test commands

  [hrs@node36 test_case]$ /usr/bin/time  -v awk 'BEGIN{for(i=1;i<=111120;i++)a[i]=i}'
       Command being timed: "awk BEGIN{for(i=1;i<=111120;i++)a[i]=i}"
       User time (seconds): 0.03
       System time (seconds): 0.01
       Percent of CPU this job got: 97%
       Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.04
       Average shared text size (kbytes): 0
       Average unshared data size (kbytes): 0
       Average stack size (kbytes): 0
       Average total size (kbytes): 0
       Maximum resident set size (kbytes): 22424
       Average resident set size (kbytes): 0
       Major (requiring I/O) page faults: 0
       Minor (reclaiming a frame) page faults: 5727
       Voluntary context switches: 1
       Involuntary context switches: 1
       Swaps: 0
       File system inputs: 0
       File system outputs: 0
       Socket messages sent: 0
       Socket messages received: 0
       Signals delivered: 0
       Page size (bytes): 4096
       Exit status: 0
  

  ``` [hrs@node36 test_case]$ /usr/bin/time -v awk ‘BEGIN{for(i=1;i<=1111120;i++)a[i]=i}’ Command being timed: “awk BEGIN{for(i=1;i<=1111120;i++)a[i]=i}” User time (seconds): 0.43 System time (seconds): 0.09 Percent of CPU this job got: 99% Elapsed (wall clock) time (h:mm:ss or m:ss): 0:00.52 Average shared text size (kbytes): 0 Average unshared data size (kbytes): 0 Average stack size (kbytes): 0 Average total size (kbytes): 0 Maximum resident set size (kbytes): 213824 Average resident set size (kbytes): 0 Major (requiring I/O) page faults: 0 Minor (reclaiming a frame) page faults: 53964 Voluntary context switches: 1 Involuntary context switches: 1 Swaps: 0 File system inputs: 0 File system outputs: 0 Socket messages sent: 0 Socket messages received: 0 Signals delivered: 0 Page size (bytes): 4096 Exit status: 0

```