From d90561dbef1525c887c9e9a9ecf15a50da5e4572 Mon Sep 17 00:00:00 2001 From: lkcl Date: Sun, 3 Jul 2022 13:48:34 +0100 Subject: [PATCH] --- openpower/sv/vector_isa_comparison.mdwn | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/openpower/sv/vector_isa_comparison.mdwn b/openpower/sv/vector_isa_comparison.mdwn index 5accba345..7825772ad 100644 --- a/openpower/sv/vector_isa_comparison.mdwn +++ b/openpower/sv/vector_isa_comparison.mdwn @@ -62,6 +62,9 @@ SIMD ISAs used features "inspired" from Scalable Vector ISAs. * PackedSIMD VSX. VSX, which has the word "Vector" in its name, is "inspired" by Vector Processing but has no "Scaling" capability, and no Predicate masking. + Both these factors put pressure on developers to use + "inline assembler unrolling" and data repetition, which in turn + is detrimental to both L1 Data and Instruction Caches. Adding Predicate Masks to the PackedSIMD VSX ISA would effectively double the number of PackedSIMD instructions (750 becomes 1,500) even if it were practical @@ -90,8 +93,8 @@ The saving grace of PackedSIMD VSX is that it did not fall to the seduction outlined in the "SIMD Considered Harmful" article . It is clear that it is expected to deploy Multi-Issue to achieve -high performance, which is a much cleaner approach that does not -result in ISA poisoning such as that suffered by x86 (AVX). +high performance, which is a much cleaner approach that has not +resulted in ISA poisoning such as that suffered by x86 (AVX). # Actual 3D GPU Architectures and ISAs (all SIMD) -- 2.30.2