time: Memory Resources

 
 1.2.2 Memory Resources
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 'M'
      Maximum resident set size of the process during its lifetime, in
      Kilobytes.
 
 't'
      Average resident set size of the process, in Kilobytes.
 
 'K'
      Average total (data+stack+text) memory use of the process, in
      Kilobytes.
 
 'D'
      Average size of the process's unshared data area, in Kilobytes.
 
 'p'
      Average size of the process's unshared stack, in Kilobytes.
 
 'X'
      Average size of the process's shared text, in Kilobytes.
 
 'Z'
      System's page size, in bytes.  This is a per-system constant, but
      varies between systems.