linux-kernel - Re: Possibility of adding -march=native to x86

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20071025214647.GX30533@stusta.de>
Date:	Thu, 25 Oct 2007 23:46:47 +0200
From:	Adrian Bunk <bunk@...nel.org>
To:	Michael Lothian <mike@...eburn.co.uk>
Cc:	Gabriel C <nix.or.die@...glemail.com>, linux-kernel@...r.kernel.org
Subject: Re: Possibility of adding -march=native to x86

On Thu, Oct 25, 2007 at 10:30:09PM +0100, Michael Lothian wrote:
> On 25/10/2007, Gabriel C <nix.or.die@...glemail.com> wrote:
> > Michael Lothian wrote:
> > >> The MPENTIUM4 option does not only set -march=pentium4, it also enables
> > >> several other options in arch/i386/Kconfig.cpu resulting in better
> > >> performance.
> > >
> > > How about an autodetect to set the right options here too using cpuid?
> > >
> > > With a warning of course that the code produced will be specifically
> > > for the native cpu that it's compiled on.
> >
> > And kill off all Distro kernels right ? IMO to set that auto magically is bad.
> >
> > Regards,
> >
> > Gabriel
> >
> Yes for something like a distro kernel it is bad but as I said before
> this isn't what this is for.
> 
> Eventually it would be nice to to a make localkernel and for a
> customised kernel to be build compiling in all pci / pci express
> drivers into the kernel and all usb devices as modules.
> 
> Auto magically detecting the cpu would be part of that
> 
> I hate getting a new piece of kit and then have to figure out from
> lspci which options need to be turned on and the the really iritation
> part of finding the option in make menuconfig

What exactly is irritating?
Please name the problems so that they can be fixed.

> Detecting the cpu and using march=native could be all part of that

You don't need march=native for this.

You have to set the right config option for your CPU and you 
automatically get the right compiler options.

> Mike

cu
Adrian

-- 

       "Is there not promise of rain?" Ling Tan asked suddenly out
        of the darkness. There had been need of rain for many days.
       "Only a promise," Lao Er said.
                                       Pearl S. Buck - Dragon Seed

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/