[Valgrind-users] How to make use of callgrind --cacheuse=yes ?

[Stephen K. <he...@st...>]

Hello,

I'm looking for a way to answer the question 'how much of a cache line did I 
use before discarding it?'.

I wrote this simple file 

 https://gist.github.com/steveire/7c3cfb0494b4708b68fe

and ran the following commands:

 g++ matrix.cpp -O0 -g
 valgrind --tool=callgrind --cacheuse=yes --instr-atstart=no ./a.out

The output shows a large value for AcCost1 because of the padding in the 
Data struct, but kcachegrind doesn't point me to the loop as the cause of 
loading that struct and using so little of it.

Is there something I'm missing here? Is the workflow of making use of the 
option --cacheuse=yes different than I assume?

Thanks,

Steve.