From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sfi-mx-1.v28.ch3.sourceforge.com ([172.29.28.121] helo=mx.sourceforge.net) by 3yr0jf1.ch3.sourceforge.com with esmtp (Exim 4.69) (envelope-from ) id 1M64RZ-0007bF-Fk for ltp-list@lists.sourceforge.net; Mon, 18 May 2009 15:07:57 +0000 Received: from e37.co.us.ibm.com ([32.97.110.158]) by 29vjzd1.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.69) id 1M64RY-00067Y-1u for ltp-list@lists.sourceforge.net; Mon, 18 May 2009 15:07:57 +0000 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e37.co.us.ibm.com (8.13.1/8.13.1) with ESMTP id n4IF7EL4025930 for ; Mon, 18 May 2009 09:07:14 -0600 Received: from d03av02.boulder.ibm.com (d03av02.boulder.ibm.com [9.17.195.168]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v9.2) with ESMTP id n4IF7cRq030944 for ; Mon, 18 May 2009 09:07:45 -0600 Received: from d03av02.boulder.ibm.com (loopback [127.0.0.1]) by d03av02.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id n4IF7Rq2023564 for ; Mon, 18 May 2009 09:07:36 -0600 Date: Mon, 18 May 2009 10:07:25 -0500 From: "Serge E. Hallyn" Message-ID: <20090518150725.GA9790@us.ibm.com> References: <4A0D13F2.8030804@cn.fujitsu.com> <20090515134519.GA21654@us.ibm.com> <1242647979.5161.12.camel@subratamodak.linux.ibm.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <1242647979.5161.12.camel@subratamodak.linux.ibm.com> Subject: Re: [LTP] [PATCH] Synchronization between two processes List-Id: Linux Test Project General Discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ltp-list-bounces@lists.sourceforge.net To: Subrata Modak Cc: ltp-list@lists.sourceforge.net Quoting Subrata Modak (subrata@linux.vnet.ibm.com): > On Fri, 2009-05-15 at 08:45 -0500, Serge E. Hallyn wrote: > > Quoting Gui Xiaohua (guixh@cn.fujitsu.com): > > > The child-process wait SIGUSR1 which would be sended by parent-process, > > > if the child-process execute sigtimedwait() after parent-process send > > > the signal, it would never receive the SIGUSR1 from parent-process. > > > I cann't make sure the SIGUSR1 be sended after child-process execute > > > sigtimedwait() with 100 percent, and i try my best. > > > > Well, in theory I suppose this could happen, but you'd have to have > > a pretty bad scheduler if the parent can do a strcmp(buf, "c:go") > > between the pipe read and signal send, while the child goes straight > > from pipe write to sigtimedwait. > > > > Have you seen this signal be missed? If not, then I'd rather assume > > things are reasonable. If you have seen this happen, then why not > > instead set up a SIGUSR1 handler in the child before doing the pipe > > write, then just sleep for 3 seconds instead of doing sigtimedwait? > > Thanks Serge. Or, if I'm being unreasonable, then at least have the parent only wait for at most 1 second, and leave the child alone. Every every ltp test is going to hang for 5 seconds... But I prefer setting the signal handler ahead of time. > Gui, > > Are you planning any further patch(s) for this ? thanks, -serge ------------------------------------------------------------------------------ Crystal Reports - New Free Runtime and 30 Day Trial Check out the new simplified licensing option that enables unlimited royalty-free distribution of the report engine for externally facing server and web deployment. http://p.sf.net/sfu/businessobjects _______________________________________________ Ltp-list mailing list Ltp-list@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ltp-list