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CaptainBlood
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Joined: 24 Jan 2010
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 Posted: Mon Feb 06, 2023 12:45 am Post subject: Is there anything like march=native in golang? |
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A few packages are using golang.
Is there any way to force generated code to be closer to instructions of a specific CPU?
Thks 4 ur attention, interest & support.
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USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. " |
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CooSee
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Joined: 20 Nov 2004
Posts: 1455
Location: Earth
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| Posted: Wed Feb 08, 2023 9:21 pm Post subject: Re: Is there anything like march=native in golang? |
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| CaptainBlood wrote: | A few packages are using golang.
Is there any way to force generated code to be closer to instructions of a specific CPU?
Thks 4 ur attention, interest & support. |
i hope this will answer question 
go env
| Code: |
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/root/.cache/go-build"
GOENV="/root/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/root/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/root/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/go"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/go/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.19.5"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="x86_64-pc-linux-gnu-gcc"
CXX="x86_64-pc-linux-gnu-g++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build3134709060=/tmp/go-build -gno-record-gcc-switches" |
snippet from go help environment
| Code: | Architecture-specific environment variables:
GOAMD64
For GOARCH=amd64, the microarchitecture level for which to compile.
Valid values are v1 (default), v2, v3, v4.
See https://golang.org/wiki/MinimumRequirements#amd64 |
from https://github.com/golang/go/wiki/MinimumRequirements#amd64
| Code: | amd64
Until Go 1.17, the Go compiler always generated x86 binaries that could be executed by any 64-bit x86 processor.
Go 1.18 introduced 4 architectural levels for AMD64. Each level differs in the set of x86 instructions that the compiler can include in the generated binaries:
GOAMD64=v1 (default): The baseline. Exclusively generates instructions that all 64-bit x86 processors can execute.
GOAMD64=v2: all v1 instructions, plus CMPXCHG16B, LAHF, SAHF, POPCNT, SSE3, SSE4.1, SSE4.2, SSSE3.
GOAMD64=v3: all v2 instructions, plus AVX, AVX2, BMI1, BMI2, F16C, FMA, LZCNT, MOVBE, OSXSAVE.
GOAMD64=v4: all v3 instructions, plus AVX512F, AVX512BW, AVX512CD, AVX512DQ, AVX512VL.
Setting, for example, GOAMD64=v3, will allow the Go compiler to use AVX2 instructions in the generated binaries (which may improve performance in some cases); but these binaries will not run on older x86 processors that don't support AVX2.
The Go toolchain may also generate newer instructions, but guarded by dynamic checks to ensure they're only executed on capable processors. For example, with GOAMD64=v1, math/bits.OnesCount will still use the POPCNT instruction if CPUID reports that it's available. Otherwise, it falls back to a generic implementation.
The Go toolchain does not currently generate any AVX512 instructions.
Note that processor is a simplification in this context. In practice, support from the entire system (firmware, hypervisor, kernel) is needed.
See section Microarchitecture support for hints on how to use microarchitecture environment variables like GOAMD64. |
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" Die Realität ist eine Illusion, die durch Mangel an ehrlicher Kommunikation entsteht "
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" Der Mensch ist von Natur aus neugierig, was am Ende übrig bleibt ist die Gier " |
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Ionen
Developer
Joined: 06 Dec 2018
Posts: 2732
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| Posted: Wed Feb 08, 2023 9:45 pm Post subject: |
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You can confirm that it's getting used in verbose logs, e.g. should see something like | Code: | | /usr/lib/go/pkg/tool/linux_amd64/asm -p internal/cpu <snip> -D GOAMD64_v3 |
No need to set anything else but GOAMD64 and it should work.
Not that Go packages I use are anything resources intensive so it doesn't change much at the end of the day  |
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CooSee
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Joined: 20 Nov 2004
Posts: 1455
Location: Earth
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| Posted: Wed Feb 08, 2023 10:01 pm Post subject: |
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| Quote: | | No need to set anything else but GOAMD64 and it should work. |
but, on my system go env shows GOAMD64_v1 and also looked in re-emerged go ebuilds - all are compiled with GOAMD64_v1
_________________
" Die Realität ist eine Illusion, die durch Mangel an ehrlicher Kommunikation entsteht "
---
" Der Mensch ist von Natur aus neugierig, was am Ende übrig bleibt ist die Gier " |
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CaptainBlood
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Joined: 24 Jan 2010
Posts: 3657
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| Posted: Wed Feb 08, 2023 10:30 pm Post subject: |
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Coosee & Ionen,
Very Interesting. Nice
Primarily I expect smaller binaries from CPU level accuracy.
Speed as a possibly side effect benefit.
recent net-vpn/ruseup-vpn upgrade shows bigger size (+14%) : | Code: | user@amd64 ~ $ pckllbin riseup-vpn
-rwxr-xr-x 1 root root 24448920 févr. 6 04:11 /usr/bin/riseup-vpn
* net-vpn/riseup-vpn-0.21.11
Total files : 53
Total size : 23.86 MiB
user@amd64 ~ $ pckllbin riseup-vpn
-rwxr-xr-x 1 root root 27151736 févr. 7 00:53 /usr/bin/riseup-vpn
* net-vpn/riseup-vpn-0.21.11_p20221113
Total files : 54
Total size : 26.44 MiB |
Because it is a daemon of some sort, memory footprint may matter in some case, e.g. low memory resources.
build log are showing
Will soon give it a try creating a dedicated config file in /etc/portage/env with:
lto & GOGCCFLAGS could be another track...
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. "
Last edited by CaptainBlood on Thu Feb 09, 2023 2:28 am; edited 1 time in total |
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CooSee
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Joined: 20 Nov 2004
Posts: 1455
Location: Earth
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| Posted: Wed Feb 08, 2023 10:40 pm Post subject: |
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just tried with export GOAMD64=v3 and the compile used it /usr/lib/go/pkg/include -D GOOS_linux -D GOARCH_amd64 -shared -D GOAMD64_v3 -o $WORK/b047/asm_linux_amd64.o ./asm_linux_amd64.s
_________________
" Die Realität ist eine Illusion, die durch Mangel an ehrlicher Kommunikation entsteht "
---
" Der Mensch ist von Natur aus neugierig, was am Ende übrig bleibt ist die Gier " |
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CaptainBlood
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Joined: 24 Jan 2010
Posts: 3657
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| Posted: Wed Feb 08, 2023 11:01 pm Post subject: |
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| Code: | pckllbin net-vpn/riseup-vpn
-rwxr-xr-x 1 root root 27134168 févr. 9 02:53 /usr/bin/riseup-vpn
* net-vpn/riseup-vpn-0.21.11_p20221113
Total files : 54
Total size : 26.42 MiB |
tiny 0.1% there.  
Thks 4 ur attention, interest & support.
_________________
USE="-* ..." in /etc/portage/make.conf here, i.e. a countermeasure to portage implicit braces, belt & diaper paradigm
LT: "I've been doing a passable imitation of the Fontana di Trevi, except my medium is mucus. Sooo much mucus. " |
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