This is a really interesting article. I was expecting some obviously biased and/or marketing horror by virtue of it being on arm.com<p>It’s actually an interesting breakdown of ways NEON differs from SSE, and how a “direct” translation may well be sub optimal. Their first example is really illustrative of this. SSE has an instruction that pulls the top(I think?) but of each register and creates an 8bit mask from those. You can do similar in NEON but the perf is apparently terrible. But NEON has an instruction that packs some bits from each register into a 64bit value, and you can go from that to the masking behaviour you were presumably trying for originally, but much faster.<p>The other examples and case studies are similarly interesting.
It improves string comparison and sorting in ClickHouse by 15%: <a href="https://github.com/ClickHouse/ClickHouse/pull/38093" rel="nofollow">https://github.com/ClickHouse/ClickHouse/pull/38093</a>
Really interesting, thanks for sharing<p>From the article also, 10-20% improvement (I guess in Instructions Per Cycle) on some str methods in glibc <a href="https://sourceware.org/git/?p=glibc.git;a=commit;h=3c9980698988ef64072f1fac339b180f52792faf" rel="nofollow">https://sourceware.org/git/?p=glibc.git;a=commit;h=3c9980698...</a>
Can anyone recommend a good practical learning resource on adding vector optimisations to C code?<p>We could use some further optimisation in the emulated screen rendering code in VICE, particularly on ARM.