From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <49757B25.8020500@domain.hid> Date: Tue, 20 Jan 2009 08:20:05 +0100 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <51CAD0CE1504444DBE77CBBE51A0135D533F9A@slcmail.slc.mew.int> In-Reply-To: <51CAD0CE1504444DBE77CBBE51A0135D533F9A@slcmail.slc.mew.int> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai-help] fpu issue List-Id: Help regarding installation and common use of Xenomai List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Steven Seeger Cc: xenomai@xenomai.org Steven Seeger wrote: > Guys, the FPU issue I've been having with a Geode GX1 and an AMD Geode > LX800 still persists. It seems that we have always had this bug, and > it's timing related. I am pretty sure that the issue revolves around the > fact that xenomai doesn't initialize the FPU in a userspace created > thread until the FPU is actually used. I realize there is a performance > gain to be had here by not having to switch it every time, but to > confirm I would like to make a patch that initializes the FPU when a > thread is created. Can someone please point me in the right direction? > > > > Thanks, > > Steven > > > > PS - Sorry to Gilles for all the bother. J No problem, really, the only reason why I did not answer is that I was busy. But having this discussion on the list is better anyway. I suggest you use the code I sent you to dump the FPU state in various places. The first place to try is before the initialization of the two volatile double variables in the user-space real-time thread. At this point you should have a clean fpu state, if it is not the case, then you will have to start dumping the FPU state in kernel-space. -- Gilles.