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:
user $grep -m1 -A3 "vendor_id" /proc/cpuinfoOnce 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:
user $touch native.cc march.cc user $LANG="en" Compile the first file:
user $gcc -fverbose-asm -march=native native.cc -S Get march, which gcc will choose:
user $grep march native.s Options passed: -D_GNU_SOURCE native.cc -march=core-avx-i -mcx16 -msahf
Now compile a second file:
user $gcc -fverbose-asm -march=core-avx-i march.cc -S Now clean the *.s files for an easy comparisons:
user $sed -i 1,/options\ enabled/d march.s user $sed -i 1,/options\ enabled/d native.s When you not set LANG on an localized system, you have now empty files.
Compare both *.s files:
user $diff march.s native.s Output empty? You found your -march=, use it. In other cases:
20,25c20,23 < # -maccumulate-outgoing-args -maes -malign-stringops -mavx < # -mavx256-split-unaligned-load -mavx256-split-unaligned-store -mcx16 < # -mf16c -mfancy-math-387 -mfp-ret-in-387 -mfsgsbase -mfxsr -mglibc < # -mieee-fp -mlong-double-80 -mmmx -mpclmul -mpopcnt -mpush-args -mrdrnd < # -mred-zone -msahf -msse -msse2 -msse3 -msse4 -msse4.1 -msse4.2 -mssse3 < # -mtls-direct-seg-refs -mxsave -mxsaveopt --- > # -maccumulate-outgoing-args -malign-stringops -mcx16 -mfancy-math-387 > # -mfp-ret-in-387 -mfsgsbase -mfxsr -mglibc -mieee-fp -mlong-double-80 > # -mmmx -mpclmul -mpopcnt -mpush-args -mred-zone -msahf -msse -msse2 -msse3 > # -msse4 -msse4.1 -msse4.2 -mssse3 -mtls-direct-seg-refs
Now guess, which switches -march=core-avx-i enable and -march=native not: -maes -mavx and some more. Now we build march.cc again with this two switches disabled:
gcc -fverbose-asm -march=core-avx-i -mno-aes -mno-avx march.cc -S sed -i 1,/options\ enabled/d march.s diff march.s native.s < # -mmmx -mpclmul -mpopcnt -mpush-args -mrdrnd -mred-zone -msahf -msse < # -msse2 -msse3 -msse4 -msse4.1 -msse4.2 -mssse3 -mtls-direct-seg-refs --- > # -mmmx -mpclmul -mpopcnt -mpush-args -mred-zone -msahf -msse -msse2 -msse3 > # -msse4 -msse4.1 -msse4.2 -mssse3 -mtls-direct-seg-refs
One switch we need to disable too: -mrdrnd
Finally set CFLAGS:
FILE
/etc/portage/make.confCFLAGS="-march=core-avx-i -mno-avx -mno-aes -mno-rdrnd -O2 -pipe"
x86/amd64
Intel
Haswell
Core i3/i5/i7 & Xeon E3/E5/E7 *V2
vendor_id : GenuineIntel cpu family : 6 model : 60 model name : Intel(R) Xeon(R) CPU E3-1271 v3 @ 3.60GHz … model : 60 model name : Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core-avx2 -O2 -pipe"
CXXFLAGS="${CFLAGS}"
Note
core-avx2 march support was introduced with GCC 4.7. If you have an earlier version of GCC, use -march=native or find cpu-specific options manually.
core-avx2 march support was introduced with GCC 4.7. If you have an earlier version of GCC, use -march=native or find cpu-specific options manually.
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
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core-avx-i -O2 -pipe"
CXXFLAGS="${CFLAGS}"
Pentium
vendor_id : GenuineIntel cpu family : 6 model : 58 model name : Intel(R) Pentium(R) CPU G2020 @ 2.90GHz
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core-avx-i -mno-avx -mno-aes -mno-rdrnd -O2 -pipe"
CXXFLAGS="${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
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=corei7-avx -O2 -pipe"
CXXFLAGS="${CFLAGS}"
Pentium
vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Pentium(R) CPU B960 @ 2.20GHz
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=corei7-avx -mno-avx -mno-aes -mno-rdrnd -O2 -pipe"
CXXFLAGS="${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
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=corei7 -O2 -pipe"
CXXFLAGS="${CFLAGS}"
Intel Core
vendor_id : GenuineIntel cpu family : 6 … model : 15 model name : Intel(R) Core(TM)2 Duo CPU T7500 @ 2.20GHz … model : 15 model name : Intel(R) Xeon(R) CPU 3040 @ 1.86GHz
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-march=core2 -O2 -pipe"
CXXFLAGS="${CFLAGS}"
Older microarchitecture
Pentium M (Dothan)
vendor_id : GenuineIntel cpu family : 6 model : 13 model name : Intel(R) Pentium(R) M processor 2.13GHz
FILE
/etc/portage/make.confCHOST="i686-pc-linux-gnu"
CFLAGS="-O2 -march=pentium-m -pipe -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"
AMD
A4/A6/A8-XXXX / XXXXM
vendor_id : AuthenticAMD cpu family : 18 model : 1 model name : AMD A8-3500M APU with Radeon(tm) HD Graphics
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-O2 -march=amdfam10 -mcx16 -mpopcnt -pipe"
CXXFLAGS="${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.
FILE
/etc/portage/make.confCHOST="x86_64-pc-linux-gnu"
CFLAGS="-O2 -march=bdver1 -mprefer-avx128 -mvzeroupper -pipe"
CXXFLAGS="${CFLAGS}"
Geode LX
vendor_id : AuthenticAMD cpu family : 5 model : 10 model name : Geode(TM) Integrated Processor by AMD PCS
FILE
/etc/portage/make.confCHOST="i486-pc-linux-gnu"
CFLAGS="-Os -pipe -march=geode -mmmx -m3dnow -fno-align-jumps -fno-align-functions -fno-align-labels -fno-align-loops -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"
arm
Note
To identify the respective ARM core of the SoC on your board, List of ARM microarchitectures and List of applications of ARM cores on Wikipedia may help.
To identify the respective ARM core of the SoC on your board, List of ARM microarchitectures and List of applications of ARM cores on Wikipedia may help.
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
FILE
/etc/portage/make.confCHOST="armv7a-hardfloat-linux-gnueabi"
CFLAGS="-O2 -march=armv7-a -mtune=cortex-a9 -mfpu=vfpv3-d16 -mfloat-abi=hard -pipe -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"
Note
This ARM core (equipped with the optional vfpv3d16 FPU but missing the NEON extension) is used in the Toshiba AC100/Dynabook AZ/Compal Paz00 Board.
This ARM core (equipped with the optional vfpv3d16 FPU but missing the NEON extension) is used in the Toshiba AC100/Dynabook AZ/Compal Paz00 Board.
ARM11
ARMv6/ARM1176JZF-S
processor : 0 model name : ARMv6-compatible processor rev 7 (v6l) BogoMIPS : 697.95 Features : half thumb fastmult vfp edsp java tls CPU implementer : 0x41 CPU architecture: 7 CPU variant : 0x0 CPU part : 0xb76 CPU revision : 7 Hardware : BCM2835 Revision : 0000 Serial : 000000000XXXXXXX
FILE
/etc/portage/make.confCHOST="armv6j-hardfloat-linux-gnueabi"
CFLAGS="-O2 -pipe -mcpu=arm1176jzf-s -mfpu=vfp -mfloat-abi=hard"
CXXFLAGS="${CFLAGS}"
Note
This ARM core is used in the first generation of the Raspberry Pi.
This ARM core is used in the first generation of the Raspberry Pi.
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
FILE
/etc/portage/make.confCHOST="armv6j-hardfloat-linux-gnueabi"
CFLAGS="-Os -march=armv6j -mcpu=arm1136jf-s -mfpu=vfp -mfloat-abi=hard -pipe -fomit-frame-pointer"
CXXFLAGS="${CFLAGS}"
ppc/ppc64
Note
-march=native almost never works on PowerPC.POWER8
processor : 0 cpu : POWER8E (raw), altivec supported clock : 3026.000000MHz revision : 2.1 (pvr 004b 0201) timebase : 512000000 platform : pSeries model : IBM pSeries (emulated by qemu) machine : CHRP IBM pSeries (emulated by qemu)
Note
Currently Gentoo does not support POWER8, but safe CFLAGS for it would look like the following.
Currently Gentoo does not support POWER8, but safe CFLAGS for it would look like the following.
FILE
/etc/portage/make.confCHOST="powerpc64le-linux-gnu"
CFLAGS="-mcpu=power8 -mtune=power8 -O2 -pipe -mabi=elfv2 -mabi=altivec -maltivec"
CXXFLAGS="${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
FILE
/etc/portage/make.confCHOST="powerpc-unknown-linux-gnu"
CFLAGS="-mcpu=cell -mtune=cell -O2 -pipe -mabi=altivec -maltivec"
CXXFLAGS="${CFLAGS}"
Note
GCC’s -mspe and -mabi=spe options are not targetting PS3 systems and IBM Cell. Instead, those options are dedicated to IBM e500. More info: https://lists.debian.org/debian-devel/2011/06/msg00592.html https://wiki.debian.org/PowerPCSPEPort
GCC’s -mspe and -mabi=spe options are not targetting PS3 systems and IBM Cell. Instead, those options are dedicated to IBM e500. More info: https://lists.debian.org/debian-devel/2011/06/msg00592.html https://wiki.debian.org/PowerPCSPEPort
G4
PPC 7447A
processor : 0 cpu : 7447A, altivec supported clock : 1666.666000MHz revision : 1.5 (pvr 8003 0105) bogomips : 33.28 timebase : 8320000 platform : PowerMac model : PowerBook5,9 machine : PowerBook5,9 motherboard : PowerBook5,9 MacRISC3 Power Macintosh detected as : 287 (PowerBook G4 17") pmac flags : 00000018 L2 cache : 512K unified pmac-generation : NewWorld
FILE
/etc/portage/make.confCHOST="powerpc-unknown-linux-gnu"
CFLAGS="-mcpu=7450 -mtune=7450 -O2 -maltivec -mabi=altivec -fno-strict-aliasing -pipe"
CXXFLAGS="${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
FILE
/etc/portage/make.confCHOST="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]
root #gcc -march=native -E -v - </dev/null 2>&1 | grep cc1/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
