System information
OProfile—System-Wide Profiler 109
----------
0x4f: No unit mask
BR_MISS_PRED_RETIRED: (counter: all))
number of mispredicted branches retired (precise) (min count: 500)
You can get the same output from opcontrol --list-events.
Specify the performance counter events with the option --event. Multiple options
are possible. This option needs an event name (from ophelp) and a sample rate, for
example:
opcontrol --event=CPU_CLK_UNHALTED:100000
WARNING: Be Careful with Low Sampling Rates with
CPU_CLK_UNHALTED
Setting sampling rates is dangerous as small rates cause the system to over-
load and freeze.
8.5 Using OProfile's GUI
The GUI for OProfile can be started as root with oprof_start, see Figure8.1,
“GUI for OProfile” (page109). Select your events and change the counter, if nec-
essary. Every green line is added to the list of checked events. Hover the mouse over
the line to see a help text in the status line below. Use the Configuration tab to set the
buffer and CPU size, the verbose option and others. Click on Start to execute OPro-
file.
Figure8.1: GUI for OProfile