From owner-freebsd-current@FreeBSD.ORG Thu May 22 18:33:39 2014 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 53126852; Thu, 22 May 2014 18:33:39 +0000 (UTC) Received: from mail.turbocat.net (mail.turbocat.net [IPv6:2a01:4f8:d16:4514::2]) (using TLSv1.1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 160912E40; Thu, 22 May 2014 18:33:38 +0000 (UTC) Received: from laptop015.home.selasky.org (cm-176.74.213.204.customer.telag.net [176.74.213.204]) (using TLSv1 with cipher ECDHE-RSA-AES128-SHA (128/128 bits)) (No client certificate requested) by mail.turbocat.net (Postfix) with ESMTPSA id DC7471FE026; Thu, 22 May 2014 20:33:37 +0200 (CEST) Message-ID: <537E432D.9060701@selasky.org> Date: Thu, 22 May 2014 20:34:21 +0200 From: Hans Petter Selasky User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:24.0) Gecko/20100101 Thunderbird/24.1.0 MIME-Version: 1.0 To: Chagin Dmitry Subject: Re: Patch for Linux Futexes References: <537DDA2E.6030609@selasky.org> <20140522182343.GA2825@dchagin.static.corbina.net> In-Reply-To: <20140522182343.GA2825@dchagin.static.corbina.net> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-multimedia@FreeBSD.org, FreeBSD Current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 22 May 2014 18:33:39 -0000 On 05/22/14 20:23, Chagin Dmitry wrote: > On Thu, May 22, 2014 at 01:06:22PM +0200, Hans Petter Selasky wrote: >> Hi, >> >> When using the Linux Skype client under FreeBSD I sometimes see that the >> Audio disappears in the one direction. When I check "ps auxw" I see >> skype is stuck on a so-called Futex. I looked into the Linux futex code >> and see that wakeup_one() is used instead of wakeup(). Maybe others can >> test too and verify if replacing wakeup_one() by wakeup() makes any >> difference in for Linux applications using Futexes. >> > > generally speaking the patch is not correct as futex_wake() should > wakeup n waiters which is specified by user space. and i think that > futex_wake() is correct. > so we must take a close look at futex_requeue() and FUTEX_WAKE_OP. > > Hi, I still see the issue with Skype, even when running with my small patch :-( I'll try to profile the threads in Skype while it is running like expected and observe any differences when it is not working, when I have some more time, using kgdb. I guess td->td_slptick can be used to figure out if a thread has been left behind, because Skype creates many threads ... Thank you for your time! --HPS