CPU 모델 별 권장 compile flags 옵션

Finding the CPU

To identify the model of the CPU, take a look inside /proc/cpuinfo for the “cpu family” and “model” numbers like so:

Once this information is found match the CPU to one listed on this page in order to find out the suggested “safe” CFLAGS.

Below is a list of CFLAGS which are to be considered “safe” for the given processors. These are the settings that should be used, especially when unsure which CFLAGS the processor needs.

Find CPU-specific options

At first, create two files and set language to English to get sed working:

Compile the first file:

Get march, which gcc will choose:

Options passed: -D_GNU_SOURCE native.cc -march=core-avx-i -mcx16 -msahf

Now compile a second file:

Now clean the *.s files for an easy comparisons:

When you not set LANG on an localized system, you have now empty files.

Compare both *.s files:

Output empty? You found your -march=, use it. In other cases:

20,25c20,23
< # -maccumulate-outgoing-args -maes -malign-stringops -mavx
< # -mavx256-split-unaligned-load -mavx256-split-unaligned-store -mcx16
< # -mf16c -mfancy-math-387 -mfp-ret-in-387 -mfsgsbase -mfxsr -mglibc
< # -mieee-fp -mlong-double-80 -mmmx -mpclmul -mpopcnt -mpush-args -mrdrnd
< # -mred-zone -msahf -msse -msse2 -msse3 -msse4 -msse4.1 -msse4.2 -mssse3
< # -mtls-direct-seg-refs -mxsave -mxsaveopt
---
> # -maccumulate-outgoing-args -malign-stringops -mcx16 -mfancy-math-387
> # -mfp-ret-in-387 -mfsgsbase -mfxsr -mglibc -mieee-fp -mlong-double-80
> # -mmmx -mpclmul -mpopcnt -mpush-args -mred-zone -msahf -msse -msse2 -msse3
> # -msse4 -msse4.1 -msse4.2 -mssse3 -mtls-direct-seg-refs

Now guess, which switches -march=core-avx-i enable and -march=native not: -maes -mavx and some more. Now we build march.cc again with this two switches disabled:

gcc -fverbose-asm -march=core-avx-i -mno-aes -mno-avx march.cc -S
sed -i 1,/options\ enabled/d march.s
diff march.s native.s

< # -mmmx -mpclmul -mpopcnt -mpush-args -mrdrnd -mred-zone -msahf -msse
< # -msse2 -msse3 -msse4 -msse4.1 -msse4.2 -mssse3 -mtls-direct-seg-refs
---
> # -mmmx -mpclmul -mpopcnt -mpush-args -mred-zone -msahf -msse -msse2 -msse3
> # -msse4 -msse4.1 -msse4.2 -mssse3 -mtls-direct-seg-refs

One switch we need to disable too: -mrdrnd

Finally set CFLAGS:

CFLAGS="-march=core-avx-i -mno-avx -mno-aes -mno-rdrnd -O2 -pipe"

x86/amd64

Intel

Haswell

Core i3/i5/i7 & Xeon E3/E5/E7 *V2

vendor_id	: GenuineIntel
cpu family	: 6
model		: 60
model name	: Intel(R) Xeon(R) CPU E3-1271 v3 @ 3.60GHz
…
model           : 60
model name      : Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core-avx2 -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Ivy Bridge

Core i3/i5/i7 & Xeon E3/E5/E7 *V1

vendor_id       : GenuineIntel
cpu family      : 6
model           : 58
model name      : Intel(R) Core(TM) i7-3610QM CPU @ 2.30GHz 

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core-avx-i -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Pentium

vendor_id	: GenuineIntel
cpu family	: 6
model		: 58
model name	: Intel(R) Pentium(R) CPU G2020 @ 2.90GHz

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core-avx-i -mno-avx -mno-aes -mno-rdrnd -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Sandy Bridge

Core i3/i5/i7 & Xeon E3/E5/E7

vendor_id	: GenuineIntel
cpu family	: 6
…
model		: 42
model name	: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz
…
model		: 45
model name	: Intel(R) Core(TM) i7-3930K CPU @ 3.20GHz
… 
model		: 42
model name	: Intel(R) Xeon(R) CPU E31245 @ 3.30GHz
… 
model           : 45
model name      : Intel(R) Xeon(R) CPU E5-2407 0 @ 2.20GHz

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=corei7-avx -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Pentium

vendor_id	: GenuineIntel
cpu family	: 6
model		: 42
model name	: Intel(R) Pentium(R) CPU B960 @ 2.20GHz

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=corei7-avx -mno-avx -mno-aes -mno-rdrnd -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Nehalem/Westmere

Core i3/i5/i7

vendor_id	: GenuineIntel
cpu family	: 6
model		: 42
model name	: Intel(R) Core(TM) i5-2400 CPU @ 3.10GHz

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=corei7 -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Intel Core

vendor_id       : GenuineIntel
cpu family      : 6
…
model		: 15
model name	: Intel(R) Core(TM)2 Duo CPU     T7500  @ 2.20GHz
…
model           : 15
model name      : Intel(R) Xeon(R) CPU            3040  @ 1.86GHz

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core2 -O2 -pipe"
CXXFLAGS="${CFLAGS}"

Older microarchitecture

Pentium M (Dothan)

vendor_id	: GenuineIntel
cpu family	: 6
model		: 13
model name	: Intel(R) Pentium(R) M processor 2.13GHz

CHOST="i686-pc-linux-gnu"
CFLAGS="-O2 -march=pentium-m -pipe -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"

AMD

A4/A6/A8-XXXX / XXXXM

vendor_id	: AuthenticAMD
cpu family	: 18
model		: 1
model name	: AMD A8-3500M APU with Radeon(tm) HD Graphics

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-O2 -march=amdfam10 -mcx16 -mpopcnt -pipe"
CXXFLAGS="${CFLAGS}"

FX-XXXX

vendor_id	: AuthenticAMD
cpu family	: 21
model		: 1
model name	: AMD FX(tm)-8150 Eight-Core Processor

Make sure and check the number listed by model on your system, the -march flag should be bdverX where X is the model number.

Due to the FPU design of the Bulldozer architecture, -mprefer-avx128 gives better FPU preformance at the cost of precision.

The -mvzeroupper switch will give much less of a preformance penalty when using both SSE and AVX, it isn’t much of a performance boost for most apps, but can provide a significant improvement when used with stuff like media-video/ffmpeg, net-misc/bfgminer or some apps in games-emulation that have some sections coded in assembly.

CHOST="x86_64-pc-linux-gnu"
CFLAGS="-O2 -march=bdver1 -mprefer-avx128 -mvzeroupper -pipe"
CXXFLAGS="${CFLAGS}"

Geode LX

vendor_id	: AuthenticAMD
cpu family	: 5
model		: 10
model name	: Geode(TM) Integrated Processor by AMD PCS

CHOST="i486-pc-linux-gnu"
CFLAGS="-Os -pipe -march=geode -mmmx -m3dnow -fno-align-jumps -fno-align-functions -fno-align-labels -fno-align-loops -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"

arm

Cortex-A

ARMv7-A/Cortex-A9 MPCore

with optional VFPv3 FPU

processor       : 0
model name      : ARMv7 Processor rev 0 (v7l)
BogoMIPS        : 2.00
Features        : half thumb fastmult vfp edsp vfpv3 vfpv3d16 tls 
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x1
CPU part        : 0xc09
CPU revision    : 0

processor       : 1
model name      : ARMv7 Processor rev 0 (v7l)
BogoMIPS        : 2.00
Features        : half thumb fastmult vfp edsp vfpv3 vfpv3d16 tls 
CPU implementer : 0x41
CPU architecture: 7
CPU variant     : 0x1
CPU part        : 0xc09
CPU revision    : 0

Hardware        : NVIDIA Tegra SoC (Flattened Device Tree)
Revision        : 0000
Serial          : 0000000000000000

CHOST="armv7a-hardfloat-linux-gnueabi"
CFLAGS="-O2 -march=armv7-a -mtune=cortex-a9 -mfpu=vfpv3-d16 -mfloat-abi=hard -pipe -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"

ARM11

ARMv6/ARM1176JZF-S

processor	: 0
model name	: ARMv6-compatible processor rev 7 (v6l)
BogoMIPS	: 697.95
Features	: half thumb fastmult vfp edsp java tls 
CPU implementer	: 0x41
CPU architecture: 7
CPU variant	: 0x0
CPU part	: 0xb76
CPU revision	: 7

Hardware	: BCM2835
Revision	: 0000
Serial		: 000000000XXXXXXX

CHOST="armv6j-hardfloat-linux-gnueabi"
CFLAGS="-O2 -pipe -mcpu=arm1176jzf-s -mfpu=vfp -mfloat-abi=hard"
CXXFLAGS="${CFLAGS}"

ARMv6/ARM1136JF-S

Processor       : ARMv6-compatible processor rev 5 (v6l)
BogoMIPS        : 791.34
Features        : swp half thumb fastmult vfp edsp java 
CPU implementer : 0x41
CPU architecture: 6TEJ
CPU variant     : 0x1
CPU part        : 0xb36
CPU revision    : 5

Hardware        : IMAPX200
Revision        : 0000
Serial          : 0000000000000000

CHOST="armv6j-hardfloat-linux-gnueabi"
CFLAGS="-Os -march=armv6j -mcpu=arm1136jf-s -mfpu=vfp -mfloat-abi=hard -pipe -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"

ppc/ppc64

POWER8

processor       : 0
cpu             : POWER8E (raw), altivec supported
clock           : 3026.000000MHz
revision        : 2.1 (pvr 004b 0201)

timebase        : 512000000
platform        : pSeries
model           : IBM pSeries (emulated by qemu)
machine         : CHRP IBM pSeries (emulated by qemu)

CHOST="powerpc64le-linux-gnu"
CFLAGS="-mcpu=power8 -mtune=power8 -O2 -pipe -mabi=elfv2 -mabi=altivec -maltivec"
CXXFLAGS="${CFLAGS}"

Cell

processor	: 0
cpu		: Cell Broadband Engine, altivec supported
clock		: 3192.000000MHz
revision	: 5.1 (pvr 0070 0501)

processor	: 1
cpu		: Cell Broadband Engine, altivec supported
clock		: 3192.000000MHz
revision	: 5.1 (pvr 0070 0501)

timebase	: 79800000
platform	: PS3
model		: SonyPS3

CHOST="powerpc-unknown-linux-gnu"
CFLAGS="-mcpu=cell -mtune=cell -O2 -pipe -mabi=altivec -maltivec"
CXXFLAGS="${CFLAGS}"

G4

PPC 7447A

processor	: 0
cpu		: 7447A, altivec supported
clock		: 1666.666000MHz
revision	: 1.5 (pvr 8003 0105)
bogomips	: 33.28
timebase	: 8320000
platform	: PowerMac
model		: PowerBook5,9
machine		: PowerBook5,9
motherboard	: PowerBook5,9 MacRISC3 Power Macintosh 
detected as	: 287 (PowerBook G4 17")
pmac flags	: 00000018
L2 cache	: 512K unified
pmac-generation	: NewWorld

CHOST="powerpc-unknown-linux-gnu"
CFLAGS="-mcpu=7450 -mtune=7450 -O2 -maltivec -mabi=altivec -fno-strict-aliasing -pipe"
CXXFLAGS="${CFLAGS}"

G3 (PPC 7XX)

processor       : 0
cpu             : 740/750
clock           : 400.000000MHz
revision        : 131.0 (pvr 0008 8300)
bogomips        : 49.93
timebase        : 24966218
platform        : PowerMac
model           : PowerBook3,1
machine         : PowerBook3,1
motherboard     : PowerBook3,1 MacRISC2 MacRISC Power Macintosh
detected as     : 70 (PowerBook Pismo)
pmac flags      : 0000001f
L2 cache        : 1024K unified
pmac-generation : NewWorld

CHOST="powerpc-unknown-linux-gnu"
CFLAGS="-mcpu=750 -Os -pipe -fno-strict-aliasing"
CXXFLAGS="${CFLAGS}"

m68k

Not in the list?

Try the following command to see if you will see something useful.

You will get something like below…

Notice the -march reply?

Get this info from Distcc Wiki Page^[1]

 /mnt/livecd/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.3/../../../libexec/gcc/x86_64-pc-linux-gnu/4.7.3/cc1 -E -quiet -v -iprefix /mnt/livecd/usr/x86_64-pc-linux-gnu/gcc-bin/4.7.3/../../../lib/gcc/x86_64-pc-linux-gnu/4.7.3/ - 
-march=corei7-avx -mcx16 -msahf -mno-movbe -maes -mpclmul -mpopcnt -mno-abm -mno-lwp -mno-fma -mno-fma4 -mno-xop -mno-bmi -mno-bmi2 -mno-tbm -mavx -mno-avx2 -msse4.2 -msse4.1 -mno-lzcnt -mno-rdrnd -mno-f16c -mno-fsgsbase --param l1-cache-size=32 --param l1-cache-line-size=64 --param l2-cache-size=10240 -mtune=corei7-avx