From owner-freebsd-stable@FreeBSD.ORG Sat May 23 17:08:18 2015 Return-Path: Delivered-To: freebsd-stable@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 C97EFAC9 for ; Sat, 23 May 2015 17:08:18 +0000 (UTC) Received: from mail-la0-x229.google.com (mail-la0-x229.google.com [IPv6:2a00:1450:4010:c03::229]) (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 4C76D1654 for ; Sat, 23 May 2015 17:08:18 +0000 (UTC) Received: by labbd9 with SMTP id bd9so29753714lab.2 for ; Sat, 23 May 2015 10:08:16 -0700 (PDT) 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=sM6ktgAbvWFU0lK3oRo3or56md2+fqkgrd6lje661y4=; b=Nxo2nSWJPz9Vw10zTwy9vi7xLisqSsPgWmUGnJlYz4bHlWKA8AtuVCc/UeZh4VTxBI 6bUxbeTQajP+5y1azuNpAE/4E4OQ5tziMzGbq2NXNy+aYShsjSJeJyTB1amz+/zJkGF4 IvjWn7bN+KQQFGRmHTziXXkjmqcZEqWRCcbXOMZIqZ5cBH69HVVdP9+6i5jCkMM2qC3+ z/VrA68xShSXMyHL9OtGSxP68MhVUvwUtgw/L2l2b4xHtjhAXGuy2eNjelPInjnW5qLD H+jqMN3hggIIiHu/yZ1Nf84Mpe3+El+1iUM/+mh7jpItHBuCxiCspzJmA1Ow8IONnMb6 0BRw== MIME-Version: 1.0 X-Received: by 10.152.203.162 with SMTP id kr2mr11198285lac.68.1432400895967; Sat, 23 May 2015 10:08:15 -0700 (PDT) Received: by 10.152.137.193 with HTTP; Sat, 23 May 2015 10:08:15 -0700 (PDT) In-Reply-To: <20150524010831.W7173@sola.nimnet.asn.au> References: <555C71C8.4080007@gmx.com> <555EDBBB.4090107@gmx.com> <20150522104213.4e083225@nonamehost.local> <20150523014640.K7173@sola.nimnet.asn.au> <20150523163014.U7173@sola.nimnet.asn.au> <20150523234646.R7173@sola.nimnet.asn.au> <20150524010831.W7173@sola.nimnet.asn.au> Date: Sat, 23 May 2015 20:08:15 +0300 Message-ID: Subject: Re: CPU frequency doesn't drop below 1200MHz (like it used to) From: Kimmo Paasiala To: Ian Smith Cc: "freebsd-stable@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 23 May 2015 17:08:18 -0000 On Sat, May 23, 2015 at 6:57 PM, Ian Smith wrote: > On Sat, 23 May 2015 17:40:26 +0300, Kimmo Paasiala wrote: > > On Sat, May 23, 2015 at 5:15 PM, Ian Smith wrote: > [..] > > > > It's an Intel Atom running amd64 version of FreeBSD stable/10: > > > > > > > > FreeBSD firewall.rdnzl.info 10.1-STABLE FreeBSD 10.1-STABLE #1 > > > > r283292: Sat May 23 01:08:03 EEST 2015 > > > > root@firewall.rdnzl.info:/usr/obj/usr/src/sys/GENERIC amd64 > > > > > > > > CPU: Intel(R) Atom(TM) CPU D510 @ 1.66GHz (1666.68-MHz K8-class CPU) > > > > Origin="GenuineIntel" Id=0x106ca Family=0x6 Model=0x1c Stepping=10 > > > > Features=0xbfebfbff > > > > Features2=0x40e31d > > > > AMD Features=0x20100800 > > > > AMD Features2=0x1 > > > > TSC: P-state invariant, performance statistics > > > > > > > > Powerd was working on 10.1-RELEASE but stopped working after upgrade > > > > to 10-STABLE and nothing was changed in BIOS settings. > [..] > > > > However, reading the other replies to this thread I get the impression > > > > that powerd(8) doesn't actually save energy on this platform and I'm > > > > better off without it? > > > > > > No, I don't think that's correct; using deeper C-states is most likely a > > > bigger win, but higher than needed CPU freq will still use extra power, > > > so run hotter. `sysctl dev.cpu` will also reveal your C-state usage. > > > > > > Reason I'm pursuing this is that this change shouldn't hurt, but it will > > > flush out those cases where people were only getting cpufreq due to use > > > of a 'relative' cpufreq driver like p4tcc, unless EST's enabled in BIOS; > > > I suspect yours may be one such case :) If not, there's a bug to fix. > > Seems _I've_ got a bug to fix; I need to stop assuming all modern Intel > CPUs are going to make SpeedStep and/or deeper C-states available :( > > > Looking deeper into this it appears I don't have speedstep (EST) > > support in the CPU it being a crappy Atom D510: > > > > http://ark.intel.com/products/43098 > > Indeed. It is rated at only 13W TDP, so relatively low power anyway. > > > This the full 'sysctl dev.cpu' output: > > > > % sysctl dev.cpu > > > dev.cpu.3.cx_usage: 100.00% last 65712us > > dev.cpu.3.cx_lowest: C1 > > dev.cpu.3.cx_supported: C1/1/0 > [..] > > dev.cpu.0.cx_usage: 100.00% last 3132us > > dev.cpu.0.cx_lowest: C1 > > dev.cpu.0.cx_supported: C1/1/0 > > dev.cpu.0.%parent: acpi0 > > dev.cpu.0.%pnpinfo: _HID=none _UID=0 > > dev.cpu.0.%location: handle=\_PR_.P001 > > dev.cpu.0.%driver: cpu > > dev.cpu.0.%desc: ACPI CPU > > dev.cpu.%parent: > > It doesn't even provide dev.cpu.0.freq, and has no deeper C-states > ('Idle States' on that page) available, so it looks like you may as well > not bother running powerd. Others maybe can offer better suggestions. > > > So I should keep those two hints in loader.conf to use p4tcc I guess? > > If this is a desktop I'd just let it run flat out, ie disable p4tcc and > acpi_throttle, have no cpufreq and forget powerd. > > If it's a laptop and power consumption on battery matters to you, you > could see if p4tcc's lower frequencies actually save any power much, by > running 'powerd -v' in a terminal while testing with different loads, or > if your 'acpiconf -i0' shows discharging rates in mA or mW, or both. > > Sorry again for my poor assumption, and thanks for the data point! > > cheers, Ian It's a firewall/router with some minimal services like nginx running. I'll just leave it like it's now without any frequency control. Thanks, -Kimmo