From owner-freebsd-questions@FreeBSD.ORG Tue Dec 9 23:05:00 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id B96C21EE; Tue, 9 Dec 2014 23:05:00 +0000 (UTC) Received: from mail-wi0-x22a.google.com (mail-wi0-x22a.google.com [IPv6:2a00:1450:400c:c05::22a]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 497D92EC; Tue, 9 Dec 2014 23:05:00 +0000 (UTC) Received: by mail-wi0-f170.google.com with SMTP id bs8so11688349wib.5 for ; Tue, 09 Dec 2014 15:04:58 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=8M4ZjLcM+5XpetWShd+SbrXov4i/y3vHTXT1bztH6Bc=; b=MmVtZvfcunztCwgdt73K9pLphEZWt+4MhHAYxE95CObi97Kh5CmetXI7yFZRbV4uqQ HQtQHipH5lDqP7jdR6QaNz1R/tXuUV5Xkrhxq1Q7ccKFsZr9+nQ6rlLW5byBiXP0gj7I Fgw4ZEOop2RdO9OmVQc6R8S7IivOJH+TGjZOWjGLPJEIL4MursGA+TkNsYyrcWdCCnOA hbO3+EeOPiPiTGY62Y02oXzY9SL7KwVDMhAlYwqgWlcyKJS4aL/t3IqknKya1HfCB4TS +AWbtgU74LyqbvSTq2HNqit8sguD7mmJcXnLTrBklseXUzKpvPtuLoLJVZJK16AsoMpy 5xPQ== MIME-Version: 1.0 X-Received: by 10.180.103.162 with SMTP id fx2mr8014463wib.42.1418166298671; Tue, 09 Dec 2014 15:04:58 -0800 (PST) Received: by 10.216.151.130 with HTTP; Tue, 9 Dec 2014 15:04:58 -0800 (PST) In-Reply-To: References: <20141208153925.5df90587@prometheus> Date: Tue, 9 Dec 2014 18:04:58 -0500 Message-ID: Subject: Re: HyperThreading on Intel Xeon Haswell, a benefit? From: grarpamp To: FreeBSD Mailing Lists Content-Type: text/plain; charset=UTF-8 Cc: FreeBSD Questions , freebsd-hardware@freebsd.org X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Dec 2014 23:05:00 -0000 > Ohartmann: > From my experience, mostly compiling FreeBSD sources from scratch > ... > a dual core, 4-thread CPU > at 3.3 GHz takes ~ 60 minutes to build world, the same as a 4-core > castrated i3 with disabled SMT. Switching off SMT on the dual core > ... > Using SMT in some FPU heavy caclulations on Sandy- and Ivy-Bridge CPUs > (Haswell is not available as XEON to me at this very moment), I see > Adrian: > I've done some basic experimenting with SMT on network loads. > ... > I've found that a memcpy heavy load (read: normal, non-zero copy Ohartmann, Adrian... Good introductory info. What were your CPU models / lines / sSpec numbers above? Anyone else? Expanding... This evaluation should not be strictly confined to Intel, after all, AMD has CMT which is similar to HTT (not clear whether it's on Opteron, FX or APU lines). Though it will probably be 2016 before AMD really capitalizes and shines on their full architecture vision. By then Intel will just shift a few gears to match. So we should probably stay on subject Intel HTT for now. http://wccftech.com/amds-high-performance-processor-cores-coming-2015-giving-modular-architecture/ http://en.wikipedia.org/wiki/Simultaneous_multithreading http://en.wikipedia.org/wiki/Hyper-threading http://forums.anandtech.com/showthread.php?t=2381524 My thought is that the available evaluations of SMT are all 'old'... discontinued processors, old compilers, old schedulers, etc, all dating back to the Intel P4 arch. So let's bring this current in terms of today's Intel Haswell and AMD APU/FX processors, with new tests and community data. (Opteron is still on an even 'older' architecture [refresh] compared to FX and APU.) http://anandtech.com/show/8742/amd-announces-carrizo-and-carrizol-next-gen-apus-for-h1-2015 http://wccftech.com/amd-berlin-server-apu-glimpse-upcoming-kaveri-apu-4-steamroller-cores-512-gcn-sps/