LinuxQuestions.org - gcc Pentium3 flags in menuconfig

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- - gcc Pentium3 flags in menuconfig (https://www.linuxquestions.org/questions/slackware-installation-40/gcc-pentium3-flags-in-menuconfig-192003/)

gcc Pentium3 flags in menuconfig

when I build the Linux kernel for a Pentium3 I get '-march=i686' as compiler option in the build process while I would have expected '-march=pentium3'. And why is the option -O2 used instead of -O3?
Do I have to correct this manually?

Regards,

Kristian Keller

These settings are set in the variable $CFLAGS

Here is some background from my /etc/make.conf file:

Code:

# Host and optimization settings

# ==============================

#

# For optimal performance, enable a CFLAGS setting appropriate for your CPU

#

# -mcpu=<cpu-type> means optimize code for the particular type of CPU without

# breaking compatibility with other CPUs.

#

# -march=<cpu-type> means to take full advantage of the ABI and instructions

# for the particular CPU; this will break compatibility with older CPUs (for

# example, -march=athlon-xp code will not run on a regular Athlon, and

# -march=i686 code will not run on a Pentium Classic.

#

# CPU types supported in gcc-3.2 and higher: athlon-xp, athlon-mp, athlon-4,

# athlon-tbird, athlon, k6, k6-2, k6-3, i386, i486, i586 (Pentium), i686

# (PentiumPro), pentium, pentium-mmx, pentiumpro, pentium2 (Celeron), pentium3,

# and pentium4. Note that Gentoo Linux 1.4 and higher include at least gcc-3.2.

#

# CPU types supported in gcc-2.95*: k6, i386, i486, i586 (Pentium), i686

# (Pentium Pro), pentium, pentiumpro Gentoo Linux 1.2 and below use gcc-2.95*

I am not sure where this variable gets set in slackware though....

The options in the makefile in /usr/src/linux/arch/i386 should be set cpu specific but they aren't, I changed the appropriate definition to 'pentium3', likewise for other processors.
The optimization -O3 results in a larger kernel as well, that doesn't seem to fit on a floppy and therefore fails to link. Probably not so interesting anyway.