What does callgrind measure?
Callgrind records the count of instructions, not the actual time spent in a function.
How do I profile with Valgrind?
To profile, you run your program under Valgrind and explicitly request the callgrind tool (if unspecified, the tool defaults to memcheck). Valgrind has written the information about the above 7 million collected events to an output file named callgrind.
What does cachegrind do?
Cachegrind simulates how your program interacts with a machine’s cache hierarchy and (optionally) branch predictor. It simulates a machine with independent first-level instruction and data caches (I1 and D1), backed by a unified second-level cache (L2).
How slow is Callgrind?
This has a huge run-time overhead, but the precision is really good and your profiling data is complete. An application running in Callgrind can be 10 to 50 times slower than normally.
How do I use Gprof?
Profiling has several steps:
- You must compile and link your program with profiling enabled. See section Compiling a Program for Profiling.
- You must execute your program to generate a profile data file. See section Executing the Program.
- You must run gprof to analyze the profile data. See section gprof Command Summary.
What is Valgrind written in?
C
Assembly language
Valgrind/Programming languages
How do I use Cachegrind?
The two steps are:
- Run your program with valgrind –tool=cachegrind in front of the normal command line invocation. When the program finishes, Cachegrind will print summary cache statistics.
- Generate a function-by-function summary, and possibly annotate source files, using the supplied cg_annotate program.
What is D1 cache?
Cache Profiling. Modern x86 machines use two levels of caching. These levels are L1 and L2, in which L1 is a split cache that consists of Instruction cache(I1) and Data cache(D1). L2 is a unified cache. The configuration of a cache means its size, associativity and number of lines.
Does valgrind work on Mac?
x and later), ARM64/Android, X86/Android (4.0 and later), MIPS32/Android, X86/FreeBSD, AMD64/FreeBSD, X86/Darwin and AMD64/Darwin (Mac OS X 10.12). Valgrind is Open Source / Free Software, and is freely available under the GNU General Public License, version 2.
How is gprof useful?
Gprof is a profiling program which collects and arranges statistics on your programs. Then, when you run your program normally (that means with any std and file i/o you would normally have), it creates “gmon.
How does gprof generate a performance profile of an application?
GPROF output consists of two parts: the flat profile and the call graph. The flat profile gives the total execution time spent in each function and its percentage of the total running time. There is an external tool called gprof2dot capable of converting the call graph from gprof into graphical form.
What is the difference between Valgrind and GDB?
The GNU Debugger (GDB) allows you to pause a running program and inspect its state. Valgrind’s memcheck monitors a program’s memory accesses and prints warnings if the program accesses invalid locations or attempts to read values that the program never set (initialized).