[gmx-users] Possible problem in trxio.c

[Erik Lindahl]

Hi,

>> Are there any news on the new assembly loops for the Opteron?
>> I read a message mentioning that gromacs 4 will know of the k8 
>> architecture.
> This will not make a big change, at least not for single precision.
> According to Erik L. the performance is identical.

Actually it's a _tiny_ bit slower, since the pointers are 64 bit. The 
big advantage of AMD64 is that there are 8 additional registers though, 
and as soon as I've rewritten the water-water core to use all 16 XMM 
registers it should be very useful. Future EMT64 (Intel's 'copy' of 
amd64) will be able to use this too.

>>
>> What do you think of creating a page on the gromacs site with the best
>> optimization flags for the major processors? I guess that most users
>> have tried this, but it is quite complex and time-consuming. I'm
>> thinking of something like a Wiki.
> Could be useful, we could do it at gromacs.org, but the disadvantage of
> a Wiki (as compared to a mailing list) is that you have to go there and
> check out stuff.
>

We try to include any new flags we know of in the automatic setup (it 
detects the compiler you are using), so post a message to the 
developers list with a clear subject so I don't miss it :-)

Cheers,

Erik