From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 9D086138334 for ; Thu, 6 Dec 2018 21:02:19 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id CB544E09CC; Thu, 6 Dec 2018 21:02:12 +0000 (UTC) Received: from blaine.gmane.org (unknown [195.159.176.226]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id 30826E09AB for ; Thu, 6 Dec 2018 21:02:12 +0000 (UTC) Received: from list by blaine.gmane.org with local (Exim 4.84_2) (envelope-from ) id 1gV0kX-00069w-6F for gentoo-user@lists.gentoo.org; Thu, 06 Dec 2018 21:59:57 +0100 X-Injected-Via-Gmane: http://gmane.org/ To: gentoo-user@lists.gentoo.org From: Nikos Chantziaras Subject: [gentoo-user] Re: CPU upgrade and LVM questions. Date: Thu, 6 Dec 2018 23:02:40 +0200 Message-ID: References: <492d8bf4-4b8d-f7f6-05d8-2473b6825fab@gmail.com> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org X-Auto-Response-Suppress: DR, RN, NRN, OOF, AutoReply Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit X-Complaints-To: usenet@blaine.gmane.org User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.3.2 In-Reply-To: <492d8bf4-4b8d-f7f6-05d8-2473b6825fab@gmail.com> Content-Language: en-US X-Archives-Salt: 7aafb7b2-2d74-49c6-a321-5050a5e1b0b8 X-Archives-Hash: 6513782df7045fe005dda37b25cb80eb On 06/12/2018 11:27, Dale wrote: > > I've bought but not yet installed a FX-8350 CPU.  I have this in my > make.conf file: > > CFLAGS="-march=native -O2 -pipe" > USE_CPU=" USE_CPU does not do anything, AFAICT. CPU features are specified in CPU_FLAGS_X86. You can get appropriate flags using the app-portage/cpuid2cpuflags tool. For example, here: $ cpuid2cpuflags CPU_FLAGS_X86: aes avx mmx mmxext pclmul popcnt sse sse2 sse3 sse4_1 sse4_2 ssse3 So in my make.conf, I use: CPU_FLAGS_X86="aes avx mmx mmxext pclmul popcnt sse sse2 sse3 sse4_1 sse4_2 ssse3" > Those were put there ages ago, likely when I built and installed Gentoo > on this rig.  Do I need to change those to something that is compatible > with both CPUs and then change to the new CPU after it is installed?  Or > will the new CPU be close enough that it won't matter?  Right now, I > don't know for sure what the new CPU supports or doesn't. Just install the new CPU and run cpuid2cpuflags to see what to put in CPU_FLAGS_X86. You can delete USE_CPU as that doesn't seem to be used for anything. > While at it, going from a 4 core CPU at 3.2GHz to a 8 core CPU at > 4.0/4.2GHz, just how much increase can I expect?  Will it double and > that's about it or will it be more than that? You won't get anything close to double the speed. The extra cores will mostly go unused, unless you use applications that make use of them. You will still get a speed up due to the newer CPU architecture and the higher frequency. > Also, since it has two > speeds, will it run at the slower or faster one?  Will it depend on > load?  I've never had a CPU with two clock speeds like this before. The two speeds specify the lower and upper speeds, depending on how many CPU cores are currently being under load, and also how much load there is. You don't have to worry about it though. It's all automatic. When you're not running anything that stressed the CPU, clock speeds are actually lower than 4GHz (some CPUs can clock down to 1GHz or so when they're idle and not doing anything.) Once something CPU-heavy runs, it will clock up to 4.2GHz. If you run something that stresses all CPU cores, then it will go to 4.0GHz to avoid overheating. But again, all this is automatic.