devRant - A fun community for developers to connect over code, tech & life as a programmer

Today was a day at work that I felt like I made a significant contribution. It was not a lot of code. Actually it was a difference of 3 characters.

I am developing an industrial server so that my employer can provide access to their machines to enterprise industrial systems. You know, the big boys toys. Probably in fucking java...

Anyway, I am putting this server on an embedded system. So naturally you want to see how much serving a server can serve. In this case the device in more processor starved than memory starved. So I bumped up the speed of the serving from 1000mS to 100mS per sample. This caused the processor to jump from 8% of one core (as read from top) to 70%. Okay, 10x more sampling then 10x approx cpu usage. That is good. I know some basic metrics for a certain amount of data for a couple of different sampling rates.

Now, I realized this really was not that much activity for this processor. I mean, it didn't seem to me that it "took much" to see a large increase of processor usage. So I started wondering about another process on the system that was eating 60 to 70 % all the time. I know it updated a screen that showed some not often needed data from its display among controlling things. Most of the time it will be in a cabinet hidden from the world. I started looking at this code and figured out where the display code was being called.

This is where it gets interesting. I didn't write this code. Another really good programmer I work with wrote this. It also seemed to be pretty standard approach. It had a timer that fired an event every 50mS. This is 20 times per second. So 20 fps if you will. I thought, What would happen if I changed this to 250mS? So I did. It dropped the processor usage to 15%! WTF?! I showed another programmer: WTF?! I showed the guy who wrote it: WTF?! I asked what does it do? He said all it does it update the display. He said: Lets take to 1000mS! I was hesitant, but okay. It dropped to 5%!

What is funny is several people all said: This is running kinda hot. It really shouldn't be this hot.

Don't assume, if you have a hunch, play with it if its safe to do so. You might just shave off 55 to 60 % cpu usage on your system.

So the code I ended up changing: "50" to "1000".