On Fri, Feb 26, 2016 at 2:52 PM, Alexander Duyck <alexander.du...@gmail.com> wrote: > > I'm still not a fan of the unaligned reads. They may be okay but it > just seems like we are going run into corner cases all over the place > where this ends up biting us.
No. Unaligned reads are not just "ok". The fact is, not doing unaligned reads is just stupid. Guys, the RISC people tried the whole "only do aligned crap". It was a mistake. It's stupid. It's wrong. Every single successful remaining RISC architecture learnt from their mistakes. That should tell you something. It should tell you that the people who tried to teach you that unaligned reads were bad were charlatans. It's *much* better to do unaligned reads in software and let hardware sort it out than to try to actively avoid them. On x86, unaligned reads have never even been expensive (except back in the dark days when people started doing vector extensions and got them wrong - those people learnt their lesson too). And on other architectures, that historically got this wrong (ARM got it *really* wrong originally), sanity eventually prevailed. So there isn't a single relevant architecture left where it would make sense to do extra work in order to only do aligned reads. The whole "unaligned reads are bad" ship sailed long ago, and it sank. Let is be. Linus