Same function uses 16% of the calls.ĥ1944 39.44 no-vmlinux no-vmlinux /no-vmlinuxĢ1390 16.24 libxul.so libxul.so pref_enumChildġ0671 8.10 libc-2.11.1.so libc-2.11.1.so _GI_strncmp_ssse3ģ007 2.28 oprofiled oprofiled /usr/bin/oprofiledĢ669 2.02 libxul.so libxul.so PL_DHashTableEnumerate With 5 Windows open, as I used to do with Firefox 13, CPU usage goes up to between 19% to 22% just for Firefox. Loading a single tab, with and with Javascript disabled for it using NoScript. Samples % image-name app-name symbol-nameģ3103 54.22 no-vmlinux no-vmlinux /no-vmlinuxĥ818 9.53 libxul.so libxul.so pref_enumChildģ934 6.44 libc-2.11.1.so libc-2.11.1.so _GI_strncmp_ssse3ġ289 2.11 oprofiled oprofiled /usr/bin/oprofiledħ52 1.23 libxul.so libxul.so PL_DHashTableEnumerateĪs you can see, 9.5% are in libxul.so, in the pref_enumChild() function. Here is the output from the above script: The following simple shell script was used: To narrow down what is using a lot of CPU, I used oprofile a system wide profiler, with the debugging symbols for Firefox.

With a single tab, with no site loaded, Firefox takes 5% of CPU This was installed 18-July-2012 to be specific, and the version is 14.0.1+build1-0ubuntu0.10.04.1.Įver since the upgrade, I am seeing high CPU usage, and it is not related to the number of tabs or windows that are open. However, things changed when I upgrade to Firefox 14 a week ago, again on Ubuntu 10.04. Other than that, Firefox was speedy and responsive. The only issue I faced was excessive disk activity and that was fixed by disabling the FireBug extension. With Firefox 13 running on Ubuntu 10.04, I had good performance, and did not suffer from this problem that I am about to describe. Ubuntu decided several months ago to forgo its policy of sticking with Firefox 3.6, and go with the latest versions from Mozilla.

Firefox takes up too much cpu