Add memory hierarchies exercise

_quarto.yml

@@ -57,7 +57,7 @@ website:
           - "exercises/parallelism/parallelism.qmd"
           - "exercises/hardware/hardware.qmd"
           - "exercises/file-and-data-systems.qmd"
-          # - "exercises/memory_hierarchies.qmd"
+          - "exercises/memory-hierarchies.qmd"
           # - "exercises/student_talks.qmd"
 
 format:

exercises/memory-hierarchies.qmd

+---
+title: "Memory Hierarchies"
+---
+
+Review the memory mountain hands-on and look into the source code:
+In `main()` the function `run()` is called for each combination of `size` and `stride`
+which in turn calls `fcyc2()` and `fcyc2_full()`.
+
+What happens there to ensure that only the desired cache effects for the test function `f` are measured?
+Describe the mechanism and why it is necessary for accurate measurements in a short paragraph.
+Refer to the code and what you learned in the lecture about it.