It might happen that your Sidekiq queue gets stuck, hanging at 0% CPU load.
When we inspected the process using strace we saw a blocking select system call.
You can get 
  backtraces for each thread
  
    Show archive.org snapshot
  
 by sending the TTIN signal to the Sidekiq process like this:
kill -TTIN $process_id
Posted by Thomas Eisenbarth to makandra dev (2014-12-11 16:21)