1. Greg Baker
  2. am-i-scheduled

Overview

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am-i-scheduled

Do you want to know how much contention there is for CPU in your virtualised environment? e.g. is VMware really scheduling your virtual machine when you need it? Have you ended up with an EC2 instance that is being shared with some other CPU-heavy jobs?

am-i-scheduled sleeps for exactly one second, checks the time and then goes back to sleep again. Every hour (configurable with the --count option), it dumps a report on latency and scheduling to stdout. Or, with the --logfile option, to another file, or with --syslog, it can write to syslog.

This is the kind of report it generates.

Reporting for 3 samples collected in the period between:
  - Thu Jul  6 14:57:32 2017
  - Thu Jul  6 15:57:59 2017
 Worst scheduling delay: 11.0209001 seconds -- Thu Jul  6 14:57:35 2017
 Mean scheduling delay: 0.006195 seconds
 Standard deviation on delay: 0.0003
 25% of the time, the delay was less than 0.000171 seconds
 Median scheduling delay was 0.002060 seconds
 25% of the time, the delay was greater than 0.002090 seconds
 Times where we received no CPU allocation for half a second (or longer): 3