Date: Mon, 22 Dec 2008 21:31:39 +0100 From: Ivan Voras <ivoras@freebsd.org> To: freebsd-questions@freebsd.org Subject: Re: Status of hyperthreading in FreeBSD Message-ID: <giotfd$oia$1@ger.gmane.org> In-Reply-To: <20081222092818.N17220@wojtek.tensor.gdynia.pl> References: <200812202039.NAA10290@lariat.net> <gimg6d$5id$1@ger.gmane.org> <20081222092818.N17220@wojtek.tensor.gdynia.pl>
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[-- Attachment #1 --] Wojciech Puchar wrote: >> >> Atom's HTT is actually pretty good - I saw up to 25% more performance >> simply by using multithreading in 7zip's compression benchmark (on >> WinXP, though). Of course, OTOH it uses about that much more transistors >> on the CPU die so it's not exactly free performance. > > really that much? i thought maybe 1-2% (just 2 sets of registers). Screenshots are available :) I was also surprised because in this case both threads use the same algorithm with the same requirements on registers. It used to be (in the days of Pentium 4) that HTT would work best if the two threads used different sets of instructions and registers (e.g. one doing integer math and another doing floating point math). I guess they made more effort this time. [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAklP+SsACgkQldnAQVacBciP+ACgsJs0OpCk7R6ce5SUbNQcbMRy 1+EAnixv9YXJF4sd4ta1RirfKNOAanss =2YNh -----END PGP SIGNATURE-----
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