From owner-freebsd-virtualization@freebsd.org Tue Oct 18 09:04:53 2016 Return-Path: Delivered-To: freebsd-virtualization@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 66605C15C2B for ; Tue, 18 Oct 2016 09:04:53 +0000 (UTC) (envelope-from nicolas.gilles@gmail.com) Received: from mail-lf0-x22d.google.com (mail-lf0-x22d.google.com [IPv6:2a00:1450:4010:c07::22d]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id D8CD46B1 for ; Tue, 18 Oct 2016 09:04:52 +0000 (UTC) (envelope-from nicolas.gilles@gmail.com) Received: by mail-lf0-x22d.google.com with SMTP id b75so336887732lfg.3 for ; Tue, 18 Oct 2016 02:04:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=WlBR5/FZc8n6LnHlgYBWZF/XUnq0ZBALc5VWj6P3fS4=; b=Dfsk7OAHwvUpDYF4j4o9SaDeQsKIuf3CCbwnuvJKhytwg5EMI5uRh9UBlZBwGfHxfN LYM3vcZjkcZ7dWxMirjwk40VzVVzdPKpAe1Lqp8PjPqK5WOJ2RHk5AJtDS+3nrNR9f9q 93lk3usKFjdWI9rrcYgSSftEI1vj3AZsxDIG0+mxn0wv4lvTqZDuQN3KvuWsz+VnWW/8 5bH6Bc4Bk8p3/SzHBSXnfO34yOevHK9G/bJiAQESu3z02yqQCu3774d4qJ5SbVd/QdKs 0lKQqvucs8u0QMAFrmeOrDHtJIwFotgz9flrrFeoV1+6xXAfqiOPXTqG5/BXUhy7h2eA 82XQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=WlBR5/FZc8n6LnHlgYBWZF/XUnq0ZBALc5VWj6P3fS4=; b=Qy6zZZf8SSlS69hXtaDBaZsJzfs3L9qHyy1f6DNgpdco77OPtGJwYpXyhkQFS+E/9v 077i2F5fSYa480hYxpltOqUpI4QwPRtkf8PDHxvrbIHBqy2tI0uchBlVlhICd414QZgo 1/5ujl5ou+B+g0y5p145KJ+W+TcZ//afflYp79ms8Cu/eoDB1u0A+gD62NMzhzrXX1AU VpGkP6RKsO8lxMlWKbESaPmUtxBACX+F2hfkVZ2DhUVe2TI61R8XOuOLW+MJq16XRfi5 nK6lZEqW1u/lIB3flx81iLSFNEulPL/5nE3vzqbjNM1mgU0On9KA5SRB7fFV8XNsjtqn ZY+A== X-Gm-Message-State: AA6/9RkXgRmv2l8SPaIUuLzqTSTXbGI+g4vLNq/a2cU1UrgKpxGcLOFZgr2E05fi7aa/Y5JGifLCgeu/FeMncw== X-Received: by 10.25.43.12 with SMTP id r12mr20312097lfr.104.1476781490138; Tue, 18 Oct 2016 02:04:50 -0700 (PDT) MIME-Version: 1.0 Received: by 10.25.195.147 with HTTP; Tue, 18 Oct 2016 02:04:49 -0700 (PDT) In-Reply-To: <20161018084107.GA60191@admin.sibptus.transneft.ru> References: <20161018015903.GA42265@admin.sibptus.transneft.ru> <58058A64.6010908@redbarn.org> <20161018084107.GA60191@admin.sibptus.transneft.ru> From: Nicolas Gilles Date: Tue, 18 Oct 2016 11:04:49 +0200 Message-ID: Subject: Re: choice of i386 vs amd64 guest To: Victor Sudakov Cc: Paul Vixie , freebsd-virtualization@freebsd.org Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 18 Oct 2016 09:04:53 -0000 On Tue, Oct 18, 2016 at 10:41 AM, Victor Sudakov wrote: > Paul Vixie wrote: >> >> > >> > When I must run several FreeBSD guests in bhyve, should I prefer i386 >> > or amd64 guests provided a guest will never need more than 2-3 GB of >> > RAM? >> >> if you're running bind9, the sizeof(void *) will dominate your heap >> size, and a 32-bit guest will be better overall, given that you don't >> need the larger addressing size. > > Those guests will be running web servers mostly. > >> >> for everything else, the larger register set on amd64 will matter more, >> and you should probably use a 64-bit guest. > > There is an opinion that 64-bit systems use up more resources than > 32-bit ones for the same tasks, it that not true? > Yes, in fact, it's not an opinion, it's a fact, the "issue" is that in amd64 pointers are 64bits wide, so take up twice as much space in memory as they would on 32-bit mode. So if your workload/datastructures are mainly manipulating lots of pointers you will see higher memory usage. On the other hand 64bit has larger register set and guaranteed presence of SSE2 instructions making it more suitable where more computations are taking place. > -- > Victor Sudakov, VAS4-RIPE, VAS47-RIPN > sip:sudakov@sibptus.tomsk.ru > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to "freebsd-virtualization-unsubscribe@freebsd.org"