title: Using time command for benchmarking
body: <p>I'm trying to use the <code>time</code> command as a simple solution for benchmarking some scripts that do a lot of text processing and makes a number of network calls. To evaluate if its a good fit, I tried doing:</p>
  
  <pre><code>/usr/bin/time -f "\n%E elapsed,\n%U user,\n%S system, \n %P CPU, \n%M
  max-mem footprint in KB, \n%t avg-mem footprint in KB, \n%K Average total
  (data+stack+text) memory,\n%F major page faults, \n%I file system
  inputs by the process, \n%O file system outputs by the process, \n%r
  socket messages received, \n%s socket messages sent, \n%x status"  yum
  install nmap
  </code></pre>
  
  <p>and got:</p>
  
  <pre><code>1:35.15 elapsed,
  3.17 user,
  0.40 system,
   3% CPU,
  0 max-mem footprint in KB,
  0 avg-mem footprint in KB,
  0 Average total (data+stack+text) memory,
  127 major page faults,
  0 file system inputs by the process, 
  0 file system outputs by the process,
  0 socket messages received,
  0 socket messages sent,
  0 status
  </code></pre>
  
  <p>which is not exactly what I was expecting - specially the 0 values. Even when I change the command to say <code>ping google.com</code>, the socket messages are 0. What's going on? Is there any alternative? </p>
  
  <p>[And I'm confused if it should stay here or be posted in serverfault]</p>