From owner-freebsd-hackers@freebsd.org Tue Aug 21 12:33:13 2018 Return-Path: Delivered-To: freebsd-hackers@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2D8ED1070905 for ; Tue, 21 Aug 2018 12:33:13 +0000 (UTC) (envelope-from sebastian.huber@embedded-brains.de) Received: from dedi548.your-server.de (dedi548.your-server.de [85.10.215.148]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id BA43581767 for ; Tue, 21 Aug 2018 12:33:12 +0000 (UTC) (envelope-from sebastian.huber@embedded-brains.de) Received: from [78.46.172.3] (helo=sslproxy06.your-server.de) by dedi548.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.85_2) (envelope-from ) id 1fs5qI-0004hM-Lq for freebsd-hackers@freebsd.org; Tue, 21 Aug 2018 14:33:02 +0200 Received: from [82.135.62.35] (helo=mail.embedded-brains.de) by sslproxy06.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89) (envelope-from ) id 1fs5qI-000Abu-BO for freebsd-hackers@freebsd.org; Tue, 21 Aug 2018 14:33:02 +0200 Received: from localhost (localhost.localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id DF90C2A165C for ; Tue, 21 Aug 2018 14:33:02 +0200 (CEST) Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id mjpjQjUMq6OE for ; Tue, 21 Aug 2018 14:33:02 +0200 (CEST) Received: from localhost (localhost.localhost [127.0.0.1]) by mail.embedded-brains.de (Postfix) with ESMTP id 9140B2A167F for ; Tue, 21 Aug 2018 14:33:02 +0200 (CEST) X-Virus-Scanned: amavisd-new at zimbra.eb.localhost Received: from mail.embedded-brains.de ([127.0.0.1]) by localhost (zimbra.eb.localhost [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id FABSBTHfrg71 for ; Tue, 21 Aug 2018 14:33:02 +0200 (CEST) Received: from [192.168.96.149] (unknown [192.168.96.149]) by mail.embedded-brains.de (Postfix) with ESMTPSA id 65CA32A165C for ; Tue, 21 Aug 2018 14:33:02 +0200 (CEST) To: FreeBSD From: Sebastian Huber Subject: epoch(9) background information? Message-ID: Date: Tue, 21 Aug 2018 14:33:00 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: quoted-printable X-Authenticated-Sender: smtp-embedded@poldinet.de X-Virus-Scanned: Clear (ClamAV 0.100.1/24862/Tue Aug 21 10:47:00 2018) X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.27 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 21 Aug 2018 12:33:13 -0000 Hello, I update currently a port of the FreeBSD network stack, etc. to the=20 real-time operating system RTEMS from the head version at 2017-04-04 to=20 the head version of today. I noticed that some read-write locks are=20 replaced by a relatively new stuff called EPOCH(9). Is there some=20 background information available for this? The man page is a bit vague=20 and searching for something named epoch on the internet is not really=20 great. For example, what is the motivation for this change? How is this=20 related to read-copy-update (RCU)? --=20 Sebastian Huber, embedded brains GmbH Address : Dornierstr. 4, D-82178 Puchheim, Germany Phone : +49 89 189 47 41-16 Fax : +49 89 189 47 41-09 E-Mail : sebastian.huber@embedded-brains.de PGP : Public key available on request. Diese Nachricht ist keine gesch=C3=A4ftliche Mitteilung im Sinne des EHUG= .