X-Recipient: archive-cygwin AT delorie DOT com X-Spam-Check-By: sourceware.org Date: Tue, 9 Mar 2010 10:18:27 -0500 From: Christopher Faylor To: cygwin AT cygwin DOT com Subject: Re: Cygwin 1.7: Concurrency Issue with Shared State Initialization Message-ID: <20100309151827.GB29316@ednor.casa.cgf.cx> Reply-To: cygwin AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com References: <20100308195656 DOT GA17237 AT ednor DOT casa DOT cgf DOT cx> <20100309113608 DOT GH6505 AT calimero DOT vinschen DOT de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20100309113608.GH6505@calimero.vinschen.de> User-Agent: Mutt/1.5.20 (2009-06-14) Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com On Tue, Mar 09, 2010 at 12:36:08PM +0100, Corinna Vinschen wrote: >On Mar 9 11:08, Schmidt, Oliver wrote: >> Hi Christopher, >> >> Fist of all thanks for your immediate feedback :-) >> >> >> /* Initialize installation root dir. */ >> >> if (!installation_root[0]) >> >> init_installation_root (); >> >> > I'll check in something tonight which attempts to solve this problem. >> >> Thanks in advance. >> >> > It's a somewhat tricky problem because adding a mutex here would slow >> > down every invocation of a cygwin program and we don't want to add to >> > the "Why is Cygwin so slow???" scenarios if we can help it. >> >> I understand your concern for sure ;-) >> >> Maybe that's the very thing you're thinking about but ... AFAIK a >> spinlock is the usual paradigm in scenarios where one doesn't >> anticipate contention but needs to be aware of it 'just in case'. With >> InterlockedCompareExchange() and Sleep() it should be quite simple to >> create one that's very efficient in the usual scenario. > >Does the below patch fix this for you? I really do have a patch sitting in my sandbox. I just forgot to test it last night. cgf -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple