Date: Sun, 25 Jul 2010 01:03:51 +0300 From: Alexander Motin <mav@FreeBSD.org> To: Norikatsu Shigemura <nork@FreeBSD.org>, freebsd-hackers@freebsd.org, freebsd-performance@freebsd.org Subject: Re: Intel TurboBoost in practice Message-ID: <4C4B6347.1070802@FreeBSD.org> In-Reply-To: <mailpost.1280004534.3728075.95172.mailing.freebsd.hackers@FreeBSD.cs.nctu.edu.tw> References: <4C4AF046.40507@FreeBSD.org> <mailpost.1280004534.3728075.95172.mailing.freebsd.hackers@FreeBSD.cs.nctu.edu.tw>
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Norikatsu Shigemura wrote: > On Sat, 24 Jul 2010 16:53:10 +0300 > Alexander Motin <mav@freebsd.org> wrote: >> PS: In this case benefit is small, but it is the least that can be >> achieved, depending on CPU model. Some models allow frequency to be >> risen by up to 6 steps (+798MHz). > > I tested on Core i7 640UM (Arrandale 1.2GHz -> 2.26GHz) with > openssl speed (w/o aesni(4)) and > /usr/src/tools/tools/crypto/cryptotest.c (w/ aesni(4)). > > http://people.freebsd.org/~nork/aesni/aes128cbc-noaesni.pdf [1] > http://people.freebsd.org/~nork/aesni/aes128cbc-aesni.pdf [2] > > In my environment, according to aes128cbc-noaesni.pdf, at least, > 30% performace up by Turbo Boost (I think). The numbers are interesting, though they are not proving much, because of many other factors may influence on result. It would be more informative to do the tests with C1 and C2/C3 states used. > And according to aes128cbc-aesni.pdf, at least, 100% performance > up by Turbo Boost (I think). This IMHO is even more questionable. Single, even boosted core shouldn't be faster then 2, 3 and 4. I would say there is some scalability problem. May be context switches, locking, or something else. -- Alexander Motin
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