Netgate 2100 High CPU usage during normal download

dandare100 · May 10, 2022, 9:23 AM

Hello

This post is for me to understand if the behaviour is correct, I am not "logging a defect :-)".

My 2100 cpu usage averages around 12%.

I have noticed now that when I have a download the CPU usage jumps to 50%-60%.
Once the download completes, the CPU usage drops back to 12%.

The reason I am trying to understand what could cause this is because I believe this is new behaviour. I did not see it in the past and there have definitely been big downloads.

Here are some graphs showing the increase in processor usage, context switches and interrupts. Please excuse the gaps on the longer term graphs, the collector is not on UPS.(yet)

Any ideas of where to start to find the cause ?

stephenw10 · May 10, 2022, 1:20 PM

What's the bandwidth through the firewall while that is logged?

CPU usage looks to be where I would expect it for a just routing and filtering traffic. At ~50% there I would guess you were moving somewhere in the 250-350Mbps range? But there are a lot of variables!

Steve

dandare100 · May 10, 2022, 4:17 PM

@stephenw10 Hello, thank you.

Correct, it was about 210Mbps.

I retried the test after your post and the CPU settled on about 30% and I noticed that the speed was slower.(probably attributed to the line)

I didn't realize that the CPU usage is as proportional as it is to the achieved download speed.

Thanks for your reply, at least the CPU usage is in the ball-park.

stephenw10 · May 10, 2022, 5:49 PM

Yes, the throughput on the 2100 is limited by the CPU so you will see usage proportionate the rate.

You will see though that the CPU usage is not equal on both CPU cores. So the limit is reached when one core is at 100% use as each NIC has one queue. Thus the total CPU usage may not show 100% at max throughput.

Steve