Bug 6368

Summary:	make.conf optimization flag
Product:	Gentoo Linux	Reporter:	Guillaume <gtaglang>
Component:	Current packages	Assignee:	Mark Guertin <mguertin>
Status:	RESOLVED FIXED
Severity:	minor
Priority:	High
Version:	unspecified
Hardware:	PPC
OS:	Linux
Whiteboard:
Package list:		Runtime testing required:	---

Description Guillaume 2002-08-12 11:36:31 UTC

Hi,

in make.conf for optimizing for G4 cpus, you can use the flag -mcpu=7400, for
recent G3 cpus, -mcpu=750 is also fine. You can find out by doing a 'cat
/proc/cpuinfo'.

I'm using:
CFLAGS=" -O2 -pipe -mcpu=750 -mmultiple -mstring "

And my cpuinfo is saying:
cpu             : 750CX
temperature     : 12 C (uncalibrated)
clock           : 499MHz
revision        : 34.21 (pvr 0008 2215)
bogomips        : 996.14
machine         : PowerBook4,1
motherboard     : PowerBook4,1 MacRISC2 MacRISC Power Macintosh
detected as     : 257 (iBook 2)
pmac flags      : 00000003
L2 cache        : 256K unified
memory          : 384MB
pmac-generation : NewWorld
(it's an ibook2 with a G3 processor)

Take a look at http://gcc.gnu.org/onlinedocs/gcc/RS-6000-and-PowerPC-Options.html.

Best regards,
    Guillaume

Comment 1 Mark Guertin 2002-08-12 13:53:54 UTC

CFLAGS=" -O2 -pipe -mcpu=750 -mmultiple -mstring " is fine for gcc 2.95.x, but
in fact breaks many things in gcc 3.2

There are new flags setup on the latest ISO's that reflect this stuff, please
check them out, they will also be added to an upcoming portage release (which
includes make.conf files)