Date: Thu, 13 Jan 2005 01:43:54 +0100 From: Anthony Atkielski <atkielski.anthony@wanadoo.fr> To: freebsd-questions@freebsd.org Subject: Re: Hyperthreading hurts 5.3? Message-ID: <786252184.20050113014354@wanadoo.fr> In-Reply-To: <41E58E53.7060606@netfence.it> References: <200501121049.j0CAnJQe028309@mp.cs.niu.edu> <828997113.20050112184556@wanadoo.fr> <41E58E53.7060606@netfence.it>
next in thread | previous in thread | raw e-mail | index | archive | help
Andrea Venturoli writes: AV> FWIW I tried numerical computations on a P4 with HT enabled: I expected AV> using 2 threads might give *at least slightly* better results, but I AV> could come to the conclusion that with 1, 2 or 4 threads the performance AV> gain (or loss) was exactly zero. Where these computations in which all threads were doing pretty much the same thing? And was it floating-point? (Doesn't the processor have just one FPU, or something like that?) AV> BTW, an old AMD 2000 XP+ would in any case almost outperform a P4 3GHz, AV> but that's another story. An AMD processor will also melt or catch fire if the CPU fan fails, whereas an Intel processor won't. I found this out the hard way, and so henceforth I'll be installing Intel processors. The cost savings one gets from buying AMD isn't enough to pay for a new motherboard or PC. AV> Obviously your use (as a server) is very different, and probably the AV> one test I have done can't expect to achieve 100% coverage even in AV> this field... but, anyway, just my 2 cents... I have no easy way to measure the performance on my system, so I'm mostly just speculating--but it seems logical. -- Anthony
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?786252184.20050113014354>