Difference between revisions of "Profilers"
|Line 70:||Line 70:|
* Huge overhead
* Huge overhead
Latest revision as of 12:24, 18 January 2012
Linux systems count with a wide variety of profilers each of with their pros and cons, there is no magic bullet, it's recommended to use more than one tool when analyzing your application, I recommend you to use at least OProfile and Valgrind.
OProfile is a non-obtrusive system-wide profiler for Linux, it can use system's performance counters to give you insights on where to optimize your code.
Helper script for simple runs (remember to run
opcontrol --setup ... once before this script):
#!/bin/sh sudo opcontrol --init sudo opcontrol --start sudo opcontrol --dump sudo opcontrol --reset $@ sudo opcontrol --stop opreport --symbols > oprof.txt
see also oprof_start
Qt3 GUI for OProfile, ships in official distribution, see http://oprofile.sourceforge.net/doc/oprofile-gui.html
One can use reports that are usable by kcachegrind with (for more instruction see http://docs.kde.org/kde3/en/kdesdk/kcachegrind/using-kcachegrind.html):
opreport -gdf | op2callgrind
Another useful application is OProfileUI, it provides a GTK+2 user interface to run and show statistics, including basic call graph.
In depth explanation can be found at:
- JFFS2 does not provide OProfile requirements, running OProfile to output data into JFFS2 partition will fail, instead use a ramfs or some external card with ext2/3:
mkdir /var/lib/oprofile # ram mount -t ramfs none /var/lib/oprofile # ext3 mount -t ext3 /dev/sda1 /var/lib/oprofile
- settings event counter too low or too high may hang your test machine. Check the recommended value for each event on specific platforms.
Unlike OProfile, GProf requires applications to be compiled with special flag
-pg so compiler will introduce marks in generated binary to measure runs. After run the
gmon.out file will be created with measured data, this file can be viewed with tools like gprof or kprof.
Outdated, but exists: http://kprof.sourceforge.net/
- Huge overhead
ARM Streamline is a commercial sample-based system performance analyzer which brings together performance counters from the core(s) and OS, time- and event-based profiling, context switch tracepoints, and instrumented messages (like printf) to provide developers with a system-to-instruction drill-down ability.
Streamline is a component of the ARM DS-5 suite, which has a 30-day evaluation version available for download.
Valgrind is tool suite for debugging and profiling. It's most famous for it's memcheck tool to check for memory leaks, invalid access, double frees and more, but also ships with interesting callgrind and cachegrind.
cachegrind will accurately simulate L1, L2 and D1 CPU caches so you can figure out what in your code is trashing your memory access.
callgrind is an extension of cachegrind that will collect call graphs.
The most famous user interface is KCachegrind
- Valgrind information in this wiki
- Valgrind Manual
- Since these are simulators, your application will run very slow, from 20 to 100 times or more.