Re: EV67 optimized libc6.1
On Tue, Apr 11, 2006 at 12:05:41PM -0400, Donsbach, Jeff wrote:
> Aurelien Jarno wrote:
> > This is only ev67. This is the mentioned architecture in the bug
> report.
> > I know almost nothing about alpha CPUs, but it seems EV67 is the CPU
> for which the gain would
> > be significant.
>
> Maybe. Maybe not. What is the nature of the changes you made? What EV67
> specific features did you use and where? Did you just recompile with
> "-march=ev67"?
The libraries are built with -march=ev67 -mtune=ev67, but also the
target is alphaev67-linux-gnu, which means that optimized assembly code
is used for some functions (the one listed in my first mail).
> If you are using native byte/word instructions in your changes, those
> are supported back into the EV56 family.
I don't know exactly. But you can have a look to the corresponding
assembly codes in the glibc sources, in sysdeps/alpha/alphaev67/
> What you might want to do is test for the CPU's capabilities (i.e. bwx
> support, mvi support, cix support) individually rather than a blanket
> "if ev67 (do a) else (do b)"
>
Well this is not possible, the kernel only returns the CPU class, from
the following list: ev4, ev5, ev56, pca56, ev6, ev67.
Bye,
Aurelien
--
.''`. Aurelien Jarno | GPG: 1024D/F1BCDB73
: :' : Debian developer | Electrical Engineer
`. `' aurel32@debian.org | aurelien@aurel32.net
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