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Bug 170782 - app-portage/genflags - didn't get the best CFLAGS on intel celeron
Summary: app-portage/genflags - didn't get the best CFLAGS on intel celeron
Status: RESOLVED WONTFIX
Alias: None
Product: Portage Development
Classification: Unclassified
Component: Third-Party Tools (show other bugs)
Hardware: All Linux
: High normal (vote)
Assignee: Robin Johnson
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2007-03-13 20:50 UTC by David Butler
Modified: 2009-04-17 04:11 UTC (History)
1 user (show)

See Also:
Package list:
Runtime testing required: ---


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Description David Butler 2007-03-13 20:50:11 UTC
genflags suggested -march=pentium2 when pentium4m works better.

suggestion:
Use the CPU flags to set processor type.  Example: If a processor is Intel and has SSE2 and does not have SSE3 than it can either be pentium-m, pentium4 or pentium4m (man gcc). It is possible to see the best we can use if the processor speed is taken in to consideration, since pentium-m is pentium3 based. As far as I know there isn't a pentium 3 that is faster than 1 Ghz, so a machine with 2.8 Ghz would be P4 compatable.  I have no idea how a program can tell wether or not the CPU is a mobile chip or not, perhaps the program could ask? but that defeats the purpose.

this is what i am using currently:
CFLAGS="-O2 -march=pentium-m -pipe -fomit-frame-pointer -mfpmath=sse -msse2 -mmmx"


info2flags output:
CHOST="i686-pc-linux-gnu"
CFLAGS="-march=pentium2 -O3 -pipe"
CXXFLAGS="-march=pentium2 -O3 -pipe"


cat /proc/cpuinfo:
processor       : 0
vendor_id       : GenuineIntel
cpu family      : 15
model           : 3
model name      : Intel(R) Celeron(R) CPU 2.80GHz
stepping        : 4
cpu MHz         : 2790.934
cache size      : 256 KB
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : yes
fpu_exception   : yes
cpuid level     : 5
wp              : yes
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe constant_tsc pni monitor ds_cpl cid xtpr
bogomips        : 5585.41
Comment 1 David Butler 2007-03-14 02:15:49 UTC
Actually i am using:
CFLAGS="-O2 -march=pentium4m -pipe -fomit-frame-pointer -mfpmath=sse -msse2 -mmmx"
Comment 2 Jeremy Olexa (darkside) (RETIRED) archtester gentoo-dev Security 2009-04-17 04:11:30 UTC
Mask message said:

# Robin H. Johnson <robbat2@gentoo.org> (20 Oct 2008)
# Masked for removal in 30 days (see bugs #120220, #137998, #170782)
# genflags should never have been born.  Output needs to be specific per GCC
# version, and that's a big change.
app-portage/genflags

so treecleaners removed it.