msandoy
Posts: 6
Joined: Wed Jul 04, 2012 8:13 pm

Low CPU usage

Thu Jul 12, 2012 1:42 pm

Hi.

I recently received my RPI, and I have it booted up with Debian. I have set up SSHD and running LXDE(localy, not via SSH). During installation of additional programs via apt-get, the CPU Usage monitor on the panel shows 100% usage, but HTOP in my ssh session shows less than 10% usage. The installation process takes incredibly long time, even for small programs with few dependencies. What is causing this strange reporting of CPU usage?

TommyboyNL
Posts: 48
Joined: Mon Jun 18, 2012 4:37 pm

Re: Low CPU usage

Thu Jul 12, 2012 2:25 pm

How much CPU is "waiting" according to top? It could be that you have a slow SD card, and that the CPU is wailing for data from SD.

msandoy
Posts: 6
Joined: Wed Jul 04, 2012 8:13 pm

Re: Low CPU usage

Thu Jul 12, 2012 4:17 pm

Hi.

I installed gkrellm to get a clearer view of the usage. You might be onto something about the SD card. It seems like the card is acting very slow. It is a Kingston 16GB class 4 card. Brand new. I have to do a bit more investigation.

TommyboyNL
Posts: 48
Joined: Mon Jun 18, 2012 4:37 pm

Re: Low CPU usage

Thu Jul 12, 2012 8:27 pm

Most SD cards aren't very good at random IO, unfortunately, that's exactly what installing an application requires.

dom
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 5664
Joined: Wed Aug 17, 2011 7:41 pm
Location: Cambridge

Re: Low CPU usage

Fri Jul 13, 2012 9:35 am

Sdcards are faster in Wheezy image, or after running rpi-update, compared to Debian Squeeze.

msandoy
Posts: 6
Joined: Wed Jul 04, 2012 8:13 pm

Re: Low CPU usage

Fri Jul 13, 2012 5:59 pm

Ok, since I'm still in the early period of testing, I think I might install another image.

msandoy
Posts: 6
Joined: Wed Jul 04, 2012 8:13 pm

Re: Low CPU usage

Mon Jul 23, 2012 7:51 pm

Finally got the raspbian image to work. ( Found out it could not be installed on a micro SD using a adaptor for the SD slot. It actually worked with squeeze.)
This has increased the responsiveness of my Pi considerably. Now it is actually usable.
Will have to get some electronic components next, and then it is just to start reading.

Return to “Troubleshooting”