Differential D45730

libc: scalar memset() in RISC-V assembly
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Authored by strajabot on Jun 25 2024, 2:24 PM.

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Reviewers

fuz
emaste
mhorne
markj

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Commits

rG40a958d5850d: libc: scalar memset() in RISC-V assembly
rG164156058e72: simd.7: add scalar memset() for RISC-V to manpage

Summary

Adds scalar implementation of memset for RISC-V
and updates the relevant manpage

os: FreeBSD
arch: riscv
        │ ./results/memset/memset_baseline │   ./results/memset/memset_scalar    │
        │              sec/op              │   sec/op     vs base                │
40                             527.5µ ± 1%   479.4µ ± 1%   -9.12% (p=0.000 n=20)
168                            254.5µ ± 1%   216.7µ ± 1%  -14.86% (p=0.000 n=20)
2k                             169.5µ ± 1%   128.4µ ± 0%  -24.24% (p=0.000 n=20)
256k                           161.2µ ± 1%   118.6µ ± 1%  -26.42% (p=0.000 n=20)
16m                            56.58m ± 0%   53.91m ± 0%   -4.72% (p=0.000 n=20)
geomean                        730.2µ        611.2µ       -16.29%
 
        │ ./results/memset/memset_baseline │    ./results/memset/memset_scalar     │
        │               B/s                │      B/s       vs base                │
40                            452.0Mi ± 1%    497.3Mi ± 1%  +10.04% (p=0.000 n=20)
168                           936.9Mi ± 1%   1100.4Mi ± 1%  +17.45% (p=0.000 n=20)
2k                            1.373Gi ± 1%    1.813Gi ± 0%  +32.00% (p=0.000 n=20)
256k                          1.444Gi ± 1%    1.962Gi ± 1%  +35.91% (p=0.000 n=20)
16m                           269.7Mi ± 0%    283.1Mi ± 0%   +4.96% (p=0.000 n=20)
geomean                       750.1Mi         896.1Mi       +19.47%

Test Plan

Tested using the provided test suite

Diff Detail

Repository

rG FreeBSD src repository

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Unit

Tests Not Applicable

Event Timeline

strajabot created this revision.Jun 25 2024, 2:24 PM

Herald added a subscriber: imp. · View Herald TranscriptJun 25 2024, 2:24 PM

strajabot requested review of this revision.Jun 25 2024, 2:24 PM

Harbormaster completed remote builds in B58345: Diff 140218.Jun 25 2024, 2:25 PM

Add license, reformat comments

Harbormaster completed remote builds in B58352: Diff 140244.Jun 25 2024, 11:27 PM

mhorne accepted this revision.Jun 26 2024, 3:57 PM

mhorne added a subscriber: mhorne.

mhorne added inline comments.

lib/libc/riscv/string/memset.S
31–33 ↗	(On Diff #140244)

This revision is now accepted and ready to land.Jun 26 2024, 3:57 PM

fuz added a reviewer: riscv.Aug 5 2025, 10:35 PM

Herald added a subscriber: ziaee. · View Herald TranscriptAug 5 2025, 10:35 PM

mhorne added inline comments.Aug 19 2025, 7:01 PM

lib/libc/riscv/string/memset.S
31–33 ↗	(On Diff #140244)	Please note this open comment.

fuz requested changes to this revision.Aug 21 2025, 5:42 PM

fuz added inline comments.

lib/libc/riscv/string/memset.S
38 ↗	(On Diff #140244)	This should be an unsigned comparison as buffer lengths are unsigned. Not that you can have a real buffer that long anyway...

This revision now requires changes to proceed.Aug 21 2025, 5:42 PM

fixup: slti -> sltiu and comments

Harbormaster completed remote builds in B67245: Diff 162596.Sep 22 2025, 9:02 PM

Should be good now.

This revision is now accepted and ready to land.Sep 22 2025, 9:27 PM

fuz added a reviewer: markj.Tue, Oct 21, 6:18 PM

Approved

fuz mentioned this in D53485: depend-cleanup.sh: clean up after riscv64 enhanced string function patch set.Thu, Oct 30, 7:32 PM

fuz added a child revision: D53485: depend-cleanup.sh: clean up after riscv64 enhanced string function patch set.Fri, Oct 31, 9:46 AM

fuz added a child revision: D53248: libc/riscv64: implement bcopy() and bzero() through memcpy() and memset().

Closed by commit rG164156058e72: simd.7: add scalar memset() for RISC-V to manpage (authored by strajabot, committed by fuz). · Explain WhyFri, Oct 31, 12:49 PM

This revision was automatically updated to reflect the committed changes.

fuz added a commit: rG164156058e72: simd.7: add scalar memset() for RISC-V to manpage.

fuz added a commit: rG40a958d5850d: libc: scalar memset() in RISC-V assembly.

fuz mentioned this in rGd59e924d2969: depend-cleanup.sh: clean up after riscv64 enhanced string function patch set.

Revision Contents
Changeset List

Path

Size

share/

man/

man7/

2 lines

Diff 165556

share/man/man7/simd.7

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