This CL adds a new generator to internal/runtime/gc/scan that generates expander
kernels in Go SIMD. This CL also includes a Go SIMD scan kernel and a
Go SIMD filter kernel.
This CL also includes the plumbing, it will use the Go SIMD kernels if
goexperiment.simd is on.
Benchmark results:
...
ScanSpanPacked/cache=tiny/pages=1/sizeclass=26/pct=80-88 354.8n ± 1% 272.4n ± 0% -23.22% (p=0.002 n=6)
ScanSpanPacked/cache=tiny/pages=1/sizeclass=26/pct=90-88 375.7n ± 0% 287.1n ± 0% -23.58% (p=0.002 n=6)
ScanSpanPacked/cache=tiny/pages=1/sizeclass=26/pct=100-88 450.0n ± 1% 327.4n ± 0% -27.24% (p=0.002 n=6)
geomean 246.5n 199.4n -19.10%
Throughput +25%.
Change-Id: Ib85e01b7de18181db9e7b6026863209a993aa85f
Reviewed-on: https://go-review.googlesource.com/c/go/+/719520
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: David Chase <drchase@google.com>
This check intends to skip size classes that are too big for scanSpan,
but it compares the size class index with a byte size. It must do the
conversion first.
For #73581.
Change-Id: I6a6a636c8d19fa3bf2a2b609870d67d33f47f66e
Reviewed-on: https://go-review.googlesource.com/c/go/+/715460
Auto-Submit: Michael Pratt <mpratt@google.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
This change imports the AVX512 GC scanning kernel from CL 593938 into a
new package, internal/runtime/gc/scan. Credit to Austin Clements for
most of this work. I did some cleanup, added support for more size
classes to the expanders, and added more testing. I also restructured
the code to make it easier and clearer to add new scan kernels for new
architectures.
For #73581.
Change-Id: I76bcbc889fa6cad73ba0084620fae084a5912e6b
Cq-Include-Trybots: luci.golang.try:gotip-linux-amd64_avx512,gotip-linux-amd64_avx512-greenteagc
Reviewed-on: https://go-review.googlesource.com/c/go/+/655280
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
