Good question. I remember back on the z890 there was a separate cache for data and instructions. I think that is still true. I do remember that writing to a storage location which was in the I-cache caused a cache flush of some sort. And that could really hurt performance. I don't know how many separate "areas" are in the cache, but I would guess that loading the D-cache from a non-cached area would "replace" the contents of at least one of the D-cache buffers.
I'm not a hardware person. I wonder if the performance would improve enough to be cost effective if data could be fetched from the I-cache. On Tue, 2012-04-10 at 18:52 -0400, Kirk Talman wrote: > Does the data intermingled with the instructions cause a performance > problem? > -- John McKown Maranatha! <><
