Hi, On Wed, Jan 16, 2013 at 6:12 PM, Fotis Georgatos <[email protected]> wrote: > On 16 Jan, 2013, at 15:04, Riccardo Murri wrote: >> In fact, I've had issue of results that changed >> because of a BIOS upgrade... > > Cool :) Explain that, this may be very interesting in this m-list!
"Cool" is definitely not the first word that came to my mind when that happened ;-) Unfortunately, there's not much I can explain: the issue is still unsolved as of today... Back in January last year, the sysadmins on the HPC cluster updated the BIOS on the compute nodes; after the upgrade, the performance of my integer matrix code dropped by some 30%. The very same binary (statically compiled) with the very same inputs would run slower. Recompiling, re-linking etc. did not bring any improvement. My best guess is that the upgrade changed some memory or cache parameters in the motherboard to more conservative defaults, but I could not investigate the issue. Ciao, R
