What is a cache write miss?
My understanding is that a write-miss occurs when we want to write data to a location in main memory whose data is not currently in its corresponding cache block.
This is similar to a read miss: if the cache block that a memory location is mapped to does not contain the data of that memory location (indicated by differing tags), then some other memory location also mapped to that same cache block is currently present, and a miss occurs.
Similarly, we &quot;miss&quot; on a write if the memory location we want to write to isn't currently &quot;in&quot; its corresponding cache block, but rather, some other memory location's data currently occupies it.
The important question that follows a write-miss is &quot;do we update the cache block corresponding to the memory location we just updated with that new data, or leave the old?&quot; Perhaps the memory-location's data already occupying that cache block is more useful or being used more frequently than what we just wrote.