Newsgroups: php.internals Path: news.php.net Xref: news.php.net php.internals:30937 Return-Path: Mailing-List: contact internals-help@lists.php.net; run by ezmlm Delivered-To: mailing list internals@lists.php.net Received: (qmail 14580 invoked by uid 1010); 14 Jul 2007 17:55:47 -0000 Delivered-To: ezmlm-scan-internals@lists.php.net Delivered-To: ezmlm-internals@lists.php.net Received: (qmail 14564 invoked from network); 14 Jul 2007 17:55:47 -0000 Received: from unknown (HELO lists.php.net) (127.0.0.1) by localhost with SMTP; 14 Jul 2007 17:55:47 -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 204.11.219.139 cause and error) X-PHP-List-Original-Sender: rasmus@lerdorf.com X-Host-Fingerprint: 204.11.219.139 mail.lerdorf.com Received: from [204.11.219.139] ([204.11.219.139:58872] helo=mail.lerdorf.com) by pb1.pair.com (ecelerity 2.1.1.9-wez r(12769M)) with ESMTP id 81/B4-05977-12E09964 for ; Sat, 14 Jul 2007 13:55:47 -0400 Received: from trainburn-lm-corp-yahoo-com.local (c-24-6-222-98.hsd1.ca.comcast.net [24.6.222.98]) (authenticated bits=0) by mail.lerdorf.com (8.14.1/8.14.1/Debian-7) with ESMTP id l6EHtexp005457 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NOT); Sat, 14 Jul 2007 10:55:41 -0700 Message-ID: <46990E11.8090209@lerdorf.com> Date: Sat, 14 Jul 2007 10:55:29 -0700 User-Agent: Thunderbird 2.0.0.4 (Macintosh/20070604) MIME-Version: 1.0 To: David Wang CC: internals@lists.php.net References: <0E6F6F20-5F50-4FC0-9B24-F960A36E0C80@procata.com> In-Reply-To: X-Enigmail-Version: 0.95.2 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV 0.90.3/3671/Sat Jul 14 09:23:26 2007 on colo.lerdorf.com X-Virus-Status: Clean Subject: Re: [PHP-DEV] Mid-term Update for Cycle Collector (Google Summer of Code Project) From: rasmus@lerdorf.com (Rasmus Lerdorf) David Wang wrote: >> Is it possible that total server throughput with gc could actually be >> better than unmodified php by preventing swapping at some higher >> level of concurrent requests? > > Yes, that's certainly true if it becomes the case that concurrent > requests take up so much memory that they induce swapping! If that > ever happens, the system will basically come to a complete standstill. > No matter what the GC does, it still will be effectively infinitely > faster than saving and retrieving information from the hard drive. It is still extremely rare for code to have cyclic references. So while GC could prevent swapping in the case of a malicious user, or in the case of a coding mistake, I don't think the general case of typical code running under normal circumstances would consume less memory with GC enabled. -Rasmus