From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Paul E. McKenney" Subject: Re: RCU stall and the system boot hang Date: Tue, 1 Dec 2015 11:55:37 -0800 Message-ID: <20151201195537.GA13568@linux.vnet.ibm.com> References: <20151127162809.GM26643@linux.vnet.ibm.com> <20151128145342.GO26643@linux.vnet.ibm.com> <20151129060537.GP26643@linux.vnet.ibm.com> <20151130171918.GR26643@linux.vnet.ibm.com> Reply-To: paulmck@linux.vnet.ibm.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-rt-users@vger.kernel.org, linux-kernel@vger.kernel.org To: fupan li Return-path: Content-Disposition: inline In-Reply-To: <20151130171918.GR26643@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: linux-rt-users.vger.kernel.org On Mon, Nov 30, 2015 at 09:19:18AM -0800, Paul E. McKenney wrote: > On Mon, Nov 30, 2015 at 02:54:13PM +0800, fupan li wrote: [ . . . ] > > No, just a normal boot, and these stalls were happened before > > systemd services running. > > Interesting. My testing show v4.1 being OK, with the first issues showing > up somewhere between v4.1 and v4.2. Or at least v4.1 is reliable enough > that is passes 42 hours of focused rcutorture testing, where v4.2 tends > to fail in under two hours. And it seems to happen only on multisocket > systems -- I seem to be able to hammer as hard as I want on my four-core > (eight hardware thread) laptop without an issue. And I take it back. After beating on it for the better part of a week, I did get one failure on my single-socket laptop. So maybe I need to make my rcutorture scripts force tests to cross socket boundaries where possible... Thanx, Paul