High load on web server after updating from Ubuntu 10.04 to Ubuntu 12.04 LTS
Check out charts which lineup to when I upgraded:
I couldn’t determine the cause of the load average increase…
Update: The issue might be memory bound. Check out this graph that show much higher swap.
After much research this appears to be a load calculation and display problem with the newer Linux kernels. The community has found Commit-ID: c308b56b5398779cd3da0f62ab26b0453494c3d4 to be the problem. The commit causes incorrect high reported load averages can be reported under conditions of light load and high enter/exit idle frequency conditions (greater then 25 hertz).A nice fellow at http://www.smythies.com/~doug/network/load_average/new.html researched the topic between tick and tickless linux kernels and the effect they had on load averages. You should check it out.