Profiling of vvdec code

[remul19]

Hi .. I would like to do a basic profiling of decoder code in linux. Normally we use gprof and while compiling we add -pg option in command line argument, and it creates extra code which is used by gprof command. I went through the build files but could not clearly understand where to add this -pg option. Could anyone please guide on how to do the profiling ?

[adamjw24]

As stated in the project description:

mkdir build
cd build
cmake .. <build options>
cmake --build . # or just `make -j`

Just add -DCMAKE_C_FLAGS=-pg -DCMAKE_CXX_FLAGS=-pg to your cmake call.

Make sure you are using a clean (empty) directory for a custom CMake build.

[adamjw24]

And use -DCMAKE_VERBOSE_MAKEFILE=1 to double-check if the compilation process does what you wanted it do.

[remul19]

Hi .. I followed the steps as you have suggested.

git clone https://github.com/fraunhoferhhi/vvdec
mkdir build
cd build
cmake .. -DCMAKE_C_FLAGS=-pg -DCMAKE_CXX_FLAGS=-pg -DCMAKE_BUILD_TYPE=RelWithDebInfo -DCMAKE_VERBOSE_MAKEFILE=1
cmake --build . 
export PATH=$PATH:/<folder_path>/bin/relwithdebinfo-static

echo $PATH . Now folder location of vvdecapp is active.
Created an output using command : vvdecapp -b input.266 -o output.yuv
Now gmon.out is created in vvdec folder.
Gave command gprof vvdecapp gmon.out > analysis.txt in vvdec folder. Got the error log as vvdecapp: No such file or directory.
So copied gmon.out into "bin\relwithdebinfo-static" folder.
Then navigated to relwithdebinfo-static folder: cd bin\relwithdebinfo-static
Gave command gprof vvdecapp gmon.out > analysis.txt.

Now analysis.txt is generated. The input file was a large one and the decodign took nearly 50 seconds in my Linux machine. But analysis.txt is having 0.00 in most of the columns (except for call count). I was expecting some non-zero values. A screenshot of analysis.txt has been attached for reference. Can anyone please guide me on how to get non-zero values in analysis.txt ?

[adamjw24]

Sorry, its up to you to figure out the usage of gprof. I never profile under Linux.

[remul19]

Hi .. I tried on another Linux machine, and it worked well with same set of commands.
Screenshot is attached as a reference ... Thanks

[1div0]

@remul19 Frankly, if you really want to profile the encoder or decoder, use the Intel VTune.