python requests taking 100% of cpu

Question

One of our API servers has an issue with CPU usage. API is written in python and configured in ubuntu AWS EC2 instance. This application uses Python 2.7 and Django 1. This can be accessed through port 80 by proxy passing. Sometimes we are getting 499 requests in our logs that time $htop value shows 100% CPU usage in the server. The only python requires are running in this server. But in AWS cloudwatch monitoring, it is not. only 40% to 50%.

PID USER      PR  NI    VIRT    RES    SHR S %CPU %MEM     TIME+ COMMAND
23086 root      20   0  815776  96056  12792 S  100  4.7   2:43.12 python                                                                      
24041 root      20   0  292756  92820  12696 S  8.0  4.5   0:33.73 python                                                                      
24072 root      20   0  815656  95696  12792 S  5.3  4.7   0:28.27 python 

Please help TIA

Answer 1

You most likely using a dual core server, and your python process is single threaded and using as much CPU as it can (one core).

Hence the discrepancy between htop and cloudwatch:

• in htop "100%" means "one cpu core", so the total CPU usage can be up to 200%
• in cloudwatch the reported cpu usage is the average between the cores, which explains the 50% (one core at 100%, the other at 0%)