Date: Tue, 8 Nov 2011 21:04:20 +0000 From: Alexander Best <arundel@freebsd.org> To: Roman Divacky <rdivacky@freebsd.org> Cc: freebsd-toolchain@freebsd.org, Dimitry Andric <dim@FreeBSD.org> Subject: Re: CPUTYPE=native handling Message-ID: <20111108210420.GA37161@freebsd.org> In-Reply-To: <20111108153856.GA90966@freebsd.org> References: <20111108002556.GA91218@freebsd.org> <4EB8E07B.5070908@FreeBSD.org> <20111108153856.GA90966@freebsd.org>
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On Tue Nov 8 11, Roman Divacky wrote:
> On Tue, Nov 08, 2011 at 08:55:39AM +0100, Dimitry Andric wrote:
> > On 2011-11-08 01:25, Alexander Best wrote:
> > > i've seen dozens of issues, where people set CPUTYPE=native. although this
> > > works in a lot of cases, it doesn't in others. why don't we simply add
> > > something like
> > >
> > > . if ${CPUTYPE} == "native"
> > > . error "bla"
> > > . endif
> > >
> > > in share/mk/bsd.cpu.mk for now? or at least for the archs, where "native" is
> > > known to cause problems.
> >
> > What does this solve? Don't you think it is better to try to fix the
> > actual problems? Some people like being able to optimize for their
>
> Yes, we definitely should aim for fixing the problems instead of working
> around them.
>
> This way both clang and freebsd benefits.
for me -march=native reports:
otaku% gcc -march=native -E -v - </dev/null
Using built-in specs.
Target: amd64-undermydesk-freebsd
Configured with: FreeBSD/amd64 system compiler
Thread model: posix
gcc version 4.2.2 20070831 prerelease [FreeBSD]
/usr/libexec/cc1 -E -quiet -v -D_LONGLONG - -march=nocona -mtune=generic
#include "..." search starts here:
#include <...> search starts here:
/usr/include/gcc/4.2
/usr/include
End of search list.
# 1 "<stdin>"
# 1 "<built-in>"
# 1 "<command-line>"
# 1 "<stdin>"
where instead of nocona, core2 would have been the better choice:
[1.000000] CPU: Intel(R) Pentium(R) Dual CPU E2160 @ 1.80GHz (1800.00-MHz K8-class CPU)
[1.000000] Origin = "GenuineIntel" Id = 0x6fd Family = 6 Model = f Stepping = 13
[1.000000] Features=0xbfebfbff<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,HTT,TM,PBE>
[1.000000] Features2=0xe39d<SSE3,DTES64,MON,DS_CPL,EST,TM2,SSSE3,CX16,xTPR,PDCM>
[1.000000] AMD Features=0x20100800<SYSCALL,NX,LM>
[1.000000] AMD Features2=0x1<LAHF>
[1.000000] TSC: P-state invariant, performance statistics
cheers.
alex
>
> roman
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