From owner-freebsd-hackers@FreeBSD.ORG Tue Mar 6 07:16:04 2012 Return-Path: Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id D92F51065787 for ; Tue, 6 Mar 2012 07:16:04 +0000 (UTC) (envelope-from maninya@gmail.com) Received: from mail-yx0-f182.google.com (mail-yx0-f182.google.com [209.85.213.182]) by mx1.freebsd.org (Postfix) with ESMTP id 78BD48FC15 for ; Tue, 6 Mar 2012 07:16:04 +0000 (UTC) Received: by yenl9 with SMTP id l9so2104105yen.13 for ; Mon, 05 Mar 2012 23:16:03 -0800 (PST) Received-SPF: pass (google.com: domain of maninya@gmail.com designates 10.101.165.33 as permitted sender) client-ip=10.101.165.33; Authentication-Results: mr.google.com; spf=pass (google.com: domain of maninya@gmail.com designates 10.101.165.33 as permitted sender) smtp.mail=maninya@gmail.com; dkim=pass header.i=maninya@gmail.com Received: from mr.google.com ([10.101.165.33]) by 10.101.165.33 with SMTP id s33mr9895508ano.70.1331018163849 (num_hops = 1); Mon, 05 Mar 2012 23:16:03 -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=3D9vwuCyumUukGE41aMa2Z+pnLH4Hs4OwrWAVLeUpow=; b=bc/wHEzAk39Q3bXI6F22nuSFvWOyBG4IEf+409ATrol7cfPfK3o7XmSzKfQnWPLyoJ Q7IExgPsjeC9SCRnfxNf1a1P5t9vMKWFRSe1UsI8ByFQMc5opfLAS++QCQqUv6yG4tE8 rAvghCyePiO1MERaZuGVVwTDuHik9lZiWcgF4RH8fOw15te0sV7zelVpa109PeYAoEn1 f5AamEjheWMntY8gB7wi4oqd5ZK1utXkJcL6eHBG/bqBJJByJ1aVnpMuSmLFkFBIgeti XVHkY1iHkh8mU0bIjZnT5r0BmB6puloA/uNKAXmn2DHbUNHaObSB/0dspM7PUXuB2mlL vNHw== MIME-Version: 1.0 Received: by 10.101.165.33 with SMTP id s33mr7826095ano.70.1331018163792; Mon, 05 Mar 2012 23:16:03 -0800 (PST) Received: by 10.147.146.9 with HTTP; Mon, 5 Mar 2012 23:16:03 -0800 (PST) In-Reply-To: <201203051221.08681.jhb@freebsd.org> References: <201203051221.08681.jhb@freebsd.org> Date: Tue, 6 Mar 2012 12:46:03 +0530 Message-ID: From: Maninya M To: freebsd-hackers@freebsd.org Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Cc: Subject: Re: CPUID and CPU STATE X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Mar 2012 07:16:05 -0000 Thank you. How do we get hardware cpuid? Can we change the number of CPUs available to the scheduler (in the scheduler code) dynamically, say completely cutting off a specific cpu core from being used at all? On 5 March 2012 22:51, John Baldwin wrote: > On Friday, March 02, 2012 2:20:00 am Maninya M wrote: > > I was unable to get this information about the cpuid variable in the > > scheduler source code. > > How does cpuid get its value from the hardware? > > The cpuid is a software ID value assigned during boot. It is not > directly related to any specific hardware IDs. > > > How is the CPUSTATES value obtained/changed with hardware in the source > > code? > > Do you mean, does cp_time[] handle hardware changes (hotplug CPUs, etc.)? > Currently that isn't supported, the kernel assumes the set of CPUs is > static for a given boot's lifetime. > > -- > John Baldwin > -- Maninya