On Tue, 10 Dec 2024 08:16:19 GMT, Quan Anh Mai <qa...@openjdk.org> wrote:
>> Hi, >> >> This is just a redo of https://github.com/openjdk/jdk/pull/13093. mostly >> just the revert of the backout. >> >> Regarding the related issues: >> >> - [JDK-8306008](https://bugs.openjdk.org/browse/JDK-8306008) and >> [JDK-8309531](https://bugs.openjdk.org/browse/JDK-8309531) have been fixed >> before the backout. >> - [JDK-8309373](https://bugs.openjdk.org/browse/JDK-8309373) was due to >> missing `ForceInline` on `AbstractVector::toBitsVectorTemplate` >> - [JDK-8306592](https://bugs.openjdk.org/browse/JDK-8306592), I have not >> been able to find the root causes. I'm not sure if this is a blocker, now I >> cannot even build x86-32 tests. >> >> Finally, I moved some implementation of public methods and methods that call >> into intrinsics to the concrete class as that may help the compiler know the >> correct types of the variables. >> >> Please take a look and leave reviews. Thanks a lot. >> >> The description of the original PR: >> >> This patch reimplements `VectorShuffle` implementations to be a vector of >> the bit type. Currently, `VectorShuffle` is stored as a byte array, and >> would be expanded upon usage. This poses several drawbacks: >> >> Inefficient conversions between a shuffle and its corresponding vector. This >> hinders the performance when the shuffle indices are not constant and are >> loaded or computed dynamically. >> Redundant expansions in `rearrange` operations. On all platforms, it seems >> that a shuffle index vector is always expanded to the correct type before >> executing the `rearrange` operations. >> Some redundant intrinsics are needed to support this handling as well as >> special considerations in the C2 compiler. >> Range checks are performed using `VectorShuffle::toVector`, which is >> inefficient for FP types since both FP conversions and FP comparisons are >> more expensive than the integral ones. >> Upon these changes, a `rearrange` can emit more efficient code: >> >> var species = IntVector.SPECIES_128; >> var v1 = IntVector.fromArray(species, SRC1, 0); >> var v2 = IntVector.fromArray(species, SRC2, 0); >> v1.rearrange(v2.toShuffle()).intoArray(DST, 0); >> >> Before: >> movabs $0x751589fa8,%r10 ; {oop([I{0x0000000751589fa8})} >> vmovdqu 0x10(%r10),%xmm2 >> movabs $0x7515a0d08,%r10 ; {oop([I{0x00000007515a0d08})} >> vmovdqu 0x10(%r10),%xmm1 >> movabs $0x75158afb8,%r10 ; {oop([I{0x000000075158afb8})} >> vmovdqu 0x10(%r10),%xmm0 >> vpand -0xddc12(%rip),%xmm0,%xmm0 # Stub::vector_int_to_byt... > > Quan Anh Mai has updated the pull request incrementally with one additional > commit since the last revision: > > Change wording on VectorLoadShuffleNode > > Co-authored-by: Jatin Bhateja <jatin.bhat...@intel.com> I am observing some performance drops in slice / unslice benchmarks, I have just completed this run and not got a chance to root cause.  Can you kindly verify once at your end. ------------- PR Comment: https://git.openjdk.org/jdk/pull/21042#issuecomment-2530801116
