On Fri, Dec 27, 2013 at 09:53:54AM +0000, Gordan Bobic wrote: > How is transparent alignment fixup going to give you back the > performance you lose from accesses straddling cache lines? You can have structs straddling cache lines and causing performance problems without alignment issues, or structs being packed too close together causing false sharing again w/o alignment being involved. If alignment problems cause performance issues, then we should deal with those performance problems. If they don't, we shouldn't worry about them. Rich. ObHack: I once worked with an architecture [68k-based VME hardware] that not only faulted on unaligned access, but also on accesses of the wrong *size* (eg. using a short-sized read instruction instead of a word-sized read instruction). Dealing with that nonsense involved a lot of compiler-specific massaging of code and some inline assembly ... -- Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones virt-top is 'top' for virtual machines. Tiny program with many powerful monitoring features, net stats, disk stats, logging, etc. http://people.redhat.com/~rjones/virt-top _______________________________________________ arm mailing list arm@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/arm
