Newsgroups: php.internals Path: news.php.net Xref: news.php.net php.internals:46872 Return-Path: Mailing-List: contact internals-help@lists.php.net; run by ezmlm Delivered-To: mailing list internals@lists.php.net Received: (qmail 56266 invoked from network); 23 Jan 2010 03:46:33 -0000 Received: from unknown (HELO lists.php.net) (127.0.0.1) by localhost with SMTP; 23 Jan 2010 03:46:33 -0000 Authentication-Results: pb1.pair.com header.from=rasmus@lerdorf.com; sender-id=unknown Authentication-Results: pb1.pair.com smtp.mail=rasmus@lerdorf.com; spf=permerror; sender-id=unknown Received-SPF: error (pb1.pair.com: domain lerdorf.com from 209.85.211.183 cause and error) X-PHP-List-Original-Sender: rasmus@lerdorf.com X-Host-Fingerprint: 209.85.211.183 mail-yw0-f183.google.com Received: from [209.85.211.183] ([209.85.211.183:55007] helo=mail-yw0-f183.google.com) by pb1.pair.com (ecelerity 2.1.1.9-wez r(12769M)) with ESMTP id 28/04-33674-8117A5B4 for ; Fri, 22 Jan 2010 22:46:32 -0500 Received: by ywh13 with SMTP id 13so1228828ywh.26 for ; Fri, 22 Jan 2010 19:46:29 -0800 (PST) Received: by 10.150.119.10 with SMTP id r10mr5147521ybc.341.1264218389458; Fri, 22 Jan 2010 19:46:29 -0800 (PST) Received: from ?192.168.200.22? (c-98-234-184-167.hsd1.ca.comcast.net [98.234.184.167]) by mx.google.com with ESMTPS id 15sm961225yxh.58.2010.01.22.19.46.27 (version=TLSv1/SSLv3 cipher=RC4-MD5); Fri, 22 Jan 2010 19:46:28 -0800 (PST) Message-ID: <4B5A7112.2060704@lerdorf.com> Date: Fri, 22 Jan 2010 19:46:26 -0800 User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: steve CC: PHP internals References: <4B4DABED.4060202@easyflirt.com> <4B4DF01A.1080103@wikimedia.org> <4B4DFBDE.1020906@lerdorf.com> <4B4E5943.3000706@wikimedia.org> <4B4E5D5B.9020805@zend.com> <4B4E6BE5.1070404@wikimedia.org> <4B4E79A6.2010904@zend.com> <4B4E8D15.60508@wikimedia.org> <57792e851001212136h12d7effaldeb75869808d8350@mail.gmail.com> <57792e851001221857m7954ee3ag4485d5cd695b6126@mail.gmail.com> In-Reply-To: <57792e851001221857m7954ee3ag4485d5cd695b6126@mail.gmail.com> X-Enigmail-Version: 0.95.7 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [PHP-DEV] About optimization From: rasmus@lerdorf.com (Rasmus Lerdorf) steve wrote: >> Having 8 cores with only 1G of ram would be a weird server config. > > A single socket quad-core with hyper-threading and 2GB RAM for a > 32-bit webserver is not weird. Not everyone is Yahoo where you can > just throw money around. Hyperthreading doesn't come anywhere near making a quad-core cpu run like an 8-core box. If you can get 25% more speed out of hyperthreading, you are doing extremely well, and that is only if the code has a lot of cache misses allowing one hyperthread to run while the other is waiting for a memory fetch. So, assuming plenty of cache misses, your scenario is approximately 5 cores and 2G of ram which is pretty far from the 8/1 ratio I thought was a weird server config. Hyperthreading can also hurt you, so most large sites I know turn it off entirely. -Rasmus