From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sog-mx-1.v43.ch3.sourceforge.com ([172.29.43.191] helo=mx.sourceforge.net) by sfs-ml-3.v29.ch3.sourceforge.com with esmtp (Exim 4.76) (envelope-from ) id 1ZsYKI-0000ji-Aq for user-mode-linux-devel@lists.sourceforge.net; Sat, 31 Oct 2015 15:44:18 +0000 Received: from www17.your-server.de ([213.133.104.17]) by sog-mx-1.v43.ch3.sourceforge.com with esmtps (TLSv1:AES256-SHA:256) (Exim 4.76) id 1ZsYKG-0003k9-7V for user-mode-linux-devel@lists.sourceforge.net; Sat, 31 Oct 2015 15:44:18 +0000 Message-ID: <1446306242.3238.16.camel@m3y3r.de> From: Thomas Meyer Date: Sat, 31 Oct 2015 16:44:02 +0100 In-Reply-To: <5634DEAB.8090909@nod.at> References: <1445416947-824802-1-git-send-email-aivanov@brocade.com> <562D236E.7020108@kot-begemot.co.uk> <562DFC90.9030308@nod.at> <5631BB4E.4010301@kot-begemot.co.uk> <1446304232.3238.8.camel@m3y3r.de> <5634DAA4.70308@nod.at> <1446304594.3238.11.camel@m3y3r.de> <5634DC7B.3010707@nod.at> <1446305051.3238.13.camel@m3y3r.de> <5634DEAB.8090909@nod.at> Mime-Version: 1.0 List-Id: The user-mode Linux development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: user-mode-linux-devel-bounces@lists.sourceforge.net Subject: Re: [uml-devel] [PATCH v3] um: Switch clocksource to hrtimers To: Richard Weinberger , Anton Ivanov Cc: "user-mode-linux-devel@lists.sourceforge.net" Am Samstag, den 31.10.2015, 16:30 +0100 schrieb Richard Weinberger: > Am 31.10.2015 um 16:24 schrieb Thomas Meyer: > > Am Samstag, den 31.10.2015, 16:21 +0100 schrieb Richard Weinberger: > > > Am 31.10.2015 um 16:16 schrieb Thomas Meyer: > > > > mhh. strange. I didn't see this behaviour on my machine, but my > > > > machine > > > > is a rare single core system so, likely a race condition while > > > > relaying > > > > the timer interrupt to the userspace process. > > > > > > Here I can trigger it by starting UML, logging in and waiting > > > ~5min. > > > Then i try to run "top" --> top hangs forever. > > > > > > > But I'm out of ideas how this could happen! > > > > > > Maybe some stupid timeslice over/underflow. > > > > > > > what happens when you send the hanging process a SIGVTALRM > > > > signal? > > > > does > > > > it proceed correctly? > > > > > > You mean sending SIGVTALRM to the UML host process? > > > > No, to the hanging userspace process, maybe the uml host process > > did > > receive a timer interrupt, but failed to relay this signal to the > > correct userspace process. > > Well, this is not what top expects and dies. > signal 26 (VTALRM) was caught by top, please > see http://www.debian.org/Bugs/Reporting > So you did send a VTALARM in the UML system to the top process? When yes then this was a misunderstanding! I wanted you to send a SIGVTALRM on the uml host system to the hanging pid. does this resolve the hang? > The problem is within UML's scheduler it does not wake top > after the nanosleep() expires. > Maybe the new clock is too imprecise, dunno. > > Thanks, > //richard > > --------------------------------------------------------------------- > --------- > _______________________________________________ > User-mode-linux-devel mailing list > User-mode-linux-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ------------------------------------------------------------------------------ _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel