On 08/15/2009 07:48 PM, Mark Knecht wrote:
On Fri, Aug 14, 2009 at 5:43 PM, Nikos Chantziaras<[email protected]> wrote:
[...]
I am doing an emerge -e system and emerge -e world anyway though since I
want to take advantage of the faster code 4.4 produces in general, but also
more specific whether or not the new "graphite" optimizer of GCC 4.4 (needs
"graphite" USE flag enabled for gcc) will give additional performance gain.
(If anyone is interested in that, you need to first add:
-floop-interchange -floop-strip-mine -floop-block
to CFLAGS/CXXFLAGS (the options enabling the Graphite optimizer) and then
"emerge -e" system and world.)
Are there any Gentoo upgrade instructions for these flags or did you
figure this out from other sources?
The upgrade instructions don't deal with CFLAGS. The specific GCC flags
are from GCC's documentation. My CFLAGS were "-O2 -march=core2 -pipe"
previously, and I just added to that the new GCC 4.4 graphite flags.
If I was going to switch to 4.4
seems like I'd want to get as much performance as I could safely get.
I'm afraid there's not enough testing on the graphite optimizer yet to
tell if those flags are as safe as -O2. In other words, you're on your own.
I'm assuming that the list above is possibly not the complete list you
might have in make.conf???
No, the complete list of CFLAGS/CXXFLAGS in my make.conf now is:
-march=core2 -O2 -floop-interchange -floop-strip-mine -floop-block -pipe
And that's it. I was using very sane CFLAGS and I don't now if those
three new "-floop" graphite flags count as "ricer CFLAGS" or not, since
as I said previously, there's not enough testing yet :P
