Gprof Tutorial

HPC.NRW
Associated Pages
+	This is an #HPC.NRW course
HPC Courses
1.	Introduction to Linux in HPC
2.	Gprof Tutorial
3.	OpenMP in Small Bites

Gprof is a free and easy-to-use profiler.

Gprof Introduction + Pascal Example

Quiz

1. What lanuages can gprof profile?

	Python, Java, Julia
	C/C++, Fortran, Pascal
	Haskell, Cobol, Brainfuck

2. How does gprof profiles an application?

	By instrumenting the application during compilation.
	Through static analysis of the source code

3. What compiler flag is used to instrument the application?

	-pg
	-pig
	--profile

How should the parameters be when running the instrumented application?

	Simple and understandable
	Representative of the usual workload
	Covering edge cases

C++ + Fortran Examples

Show gprof in real world examples and introduce call graph.

Quiz

1. What is a call graph?

	An android app to show incoming callers
	A hierarchy diagram of function calls in a given profile
	Instructions of how to call for help during emergencies

2. How do you generate a callgraph of a gprof profile?

	gprof --call-graph
	gprof
	gprof --graph

{{hidden begin |title = 3. What is gprof2dot?

	Third party script for call graph visualization via the "dot" library
	Gprof feature to export profiles as a pdf
	A fork of the beta version of gprof2

{{hidden begin |title = 4. Does gprof work with MPI applications?

	No, gprof only works with sequential applications
	Yes, parallel profiling is the main use case of gprof
	Yes, but gprof cannot differentiate between individual threads/processes

{{hidden begin |title = 5. How much overhead does gprof produce?

	None
	Little
	Much