From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephane Eranian Date: Mon, 03 Feb 2003 21:36:26 +0000 Subject: Re: [Linux-ia64] Preempt problems Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org Peter, On Tue, Feb 04, 2003 at 07:17:01AM +1100, Peter Chubb wrote: > > Hi David, > Just a heads up --- there are still two major problems with the > patch I submitted for preemption support, so I suggest you don't merge > it yet (although I'd very much appreciate having it reviewed and > tested by third parties). > > The two problems I see are: > -- perfmon missing interrupts *even with CONFIG_PREEMPT turned > off!* As for perfmon, there are some known issues with perfmon and the O(1) scheduler (deadlocks during ctxsw in SMP). I am not sure it affects your particular test case. I had postponed fixing this because I am working on a new perfmon code base for 2.5 in which (hopefully) all problems are gone. However a somewhat related issue came up last week and I decided to fix some of the problems. I will try to give a new patch to David this week. As for preemption and perfmon, I haven't had a chance to look at the patch yet. There are some assumptions about not being preemptable at several places. -- -Stephane