-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 I guess that I should have specified, that those comments were only relevant to benchmarks and CPU bound configurations.
Ed Hill wrote: > On Sat, 2005-07-23 at 08:02 -0400, Kevin Flanagan wrote: > > >>The up side is performance, while it's not as linear as SMP, it's a >>performance gain just how much depends on your OS and applications. The >>best numbers I have heard are 40% to 60% performance gain. > > >>All of that said, I would expect this new Intel CPU to appear as 4 to >>the OS and software. I haven't seen a real performance gain from >>hyperthreading, but I haven't done very fine level studying of a system, >>just the "feel of it". Dual core should offer real performance gains for >>some things, but mostly it'll just behave as if it were an SMP system. > > > So which is it? 40--60% or nothing? > > In our testing we've seen only one application (an NFS server) that saw > more than 10% improvement and it was ~15%. And yes, we were using a 2.6 > kernel with the HT-aware scheduler. > > The vast majority of the applications that we run are memory-bandwidth > limited and, in those cases, HT does basically nothing (all <1% and > sometimes *negative*) to help. If you're one of those (rare?) folks > that isn't memory bandwidth limited, then perhaps you'll see a little > improvement. But for most folks the memory system is the bottleneck and > adding more processors (either real or virtual) without increasing bw is > utterly pointless. > > Ed > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.6 (GNU/Linux) iD8DBQFC4mK3hW0MDKygik8RAnUCAKCHzQ9DV4XwLNL9IqDkbcGlsPqqpgCglL5p VNEjhmUfNpRLyS8A23eeg1w= =ZscK -----END PGP SIGNATURE----- -- TriLUG mailing list : http://www.trilug.org/mailman/listinfo/trilug TriLUG Organizational FAQ : http://trilug.org/faq/ TriLUG Member Services FAQ : http://members.trilug.org/services_faq/ TriLUG PGP Keyring : http://trilug.org/~chrish/trilug.asc
