From owner-freebsd-stable@FreeBSD.ORG Mon Mar 25 14:31:42 2013 Return-Path: Delivered-To: stable@FreeBSD.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id B7D3A95C for ; Mon, 25 Mar 2013 14:31:42 +0000 (UTC) (envelope-from melifaro@FreeBSD.org) Received: from mail.ipfw.ru (unknown [IPv6:2a01:4f8:120:6141::2]) by mx1.freebsd.org (Postfix) with ESMTP id 793732EC for ; Mon, 25 Mar 2013 14:31:42 +0000 (UTC) Received: from [2a02:6b8:0:401:222:4dff:fe50:cd2f] (helo=dhcp170-36-red.yandex.net) by mail.ipfw.ru with esmtpsa (TLSv1:CAMELLIA256-SHA:256) (Exim 4.76 (FreeBSD)) (envelope-from ) id 1UK8UO-000E55-VA; Mon, 25 Mar 2013 18:35:09 +0400 Message-ID: <51505FC0.3040709@FreeBSD.org> Date: Mon, 25 Mar 2013 18:31:28 +0400 From: "Alexander V. Chernikov" User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Eric van Gyzen Subject: Re: [patch] IPMI KCS can drop the lock while servicing a request References: <514E6ED8.9040305@vangyzen.net> <514F8061.7070206@FreeBSD.org> In-Reply-To: <514F8061.7070206@FreeBSD.org> X-Enigmail-Version: 1.4.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: stable@FreeBSD.org X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 25 Mar 2013 14:31:42 -0000 On 25.03.2013 02:38, Alexander V. Chernikov wrote: > On 24.03.2013 07:11, Eric van Gyzen wrote: >> At work, we discovered that our application's IPMI thread would often >> use a lot of CPU time. The KCS thread uses DELAY to wait for the BMC, so >> it can run without sleeping for a "long" time with a slow BMC. It also >> holds the ipmi_softc.ipmi_lock during this time. When using adaptive >> mutexes, an application thread that wants to operate on the >> ipmi_pending_requests list will also spin during this same time. > We suffer from the same problem, too. >> >> We see no reason that the KCS thread needs to hold the lock while >> servicing a request. We've been running with the attached patch for a > Well, this seems to be true. I'll try to commit something like this > patch in several days. Done in r248705. > >> few months, with no ill effects. >> >> Eric >> >> >> _______________________________________________ >> freebsd-stable@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-stable >> To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > > _______________________________________________ > freebsd-stable@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-stable > To unsubscribe, send any mail to "freebsd-stable-unsubscribe@freebsd.org" > -- WBR, Alexander