From owner-svn-src-all@freebsd.org Mon Aug 1 23:02:28 2016 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 057F5BACD16; Mon, 1 Aug 2016 23:02:28 +0000 (UTC) (envelope-from mjguzik@gmail.com) Received: from mail-wm0-x235.google.com (mail-wm0-x235.google.com [IPv6:2a00:1450:400c:c09::235]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 9E58A1A88; Mon, 1 Aug 2016 23:02:27 +0000 (UTC) (envelope-from mjguzik@gmail.com) Received: by mail-wm0-x235.google.com with SMTP id o80so264765305wme.1; Mon, 01 Aug 2016 16:02:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=kVkyaNsEMSKeRl2OrVXN+xfxS6mtZXZFz2YA24MWNTA=; b=Q0yajmHx/+a/ltDgV59PKeChyuK+zbou2Aqd1RwGUQ6mSmfd2l8lUaVrYFiuUjIDPv 8gxEmgI3yxyHydEyKS+cz6zjNBohXdjAxwoKyT2wbnYr2xhELpNX1W/VNMd01LT5psUo 1hNmL5ofZpsNKBBX8sFqEHAH/NvQUEsrRDk9zw56ZN4/jI9alRCkoFxjz20V+PcN+n0o IKo0C70Ez5n0dW5XR2oLDKb3jNGG9THu3E1Yhp/uyC59qwT4tAd9cWjuub1Y6/yvO9qS RG/526QVgn29Kvu5o/y4z2fKcXMLmnc+VArXwAsWpJiFFZdZSjrtP2tAfR8JVTkLXwt2 aWrQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=kVkyaNsEMSKeRl2OrVXN+xfxS6mtZXZFz2YA24MWNTA=; b=ho2f14RTKIewUEJw3zbbmvM86G1aXRv72pdMQ3ZSv+I28/PW8mQjOkQ4QQOaSsot4X g8xbuHx+RSjqnx3e0wgC109esv5HX/iCbk3iSTMbAnQpyOdpS9xGZ5a8rvCKrz71jCI3 LYrIJm2SOI/aDHw+leqUZhH943Ykm+3MM0ErIcRQYmIvoznToneUyRQz2GeRrBjwtQ2r GBR53u6tZIPI3pGHyB8RpE7Xm5cA47jU2hCz96WKN4OYbxOMldZqFy/P4qhoSO+sF1EM Z4NvjiElYde8KbfzrUCCg5RzQ+jOjNmVmPXjaPX+g89rZD7j5qGQ8/jMi8pGp8FQeaC1 VGaQ== X-Gm-Message-State: AEkoout8E6sIiUB+QgZIL0M69vp2YQTHDxMkYHJ0ea5250WUbZPGby/Y3YMDO9gJF78wog== X-Received: by 10.194.148.19 with SMTP id to19mr58644087wjb.81.1470092545953; Mon, 01 Aug 2016 16:02:25 -0700 (PDT) Received: from dft-labs.eu (n1x0n-1-pt.tunnel.tserv5.lon1.ipv6.he.net. [2001:470:1f08:1f7::2]) by smtp.gmail.com with ESMTPSA id yz6sm32556279wjb.35.2016.08.01.16.02.25 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Mon, 01 Aug 2016 16:02:25 -0700 (PDT) Date: Tue, 2 Aug 2016 01:02:23 +0200 From: Mateusz Guzik To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r303643 - in head/sys: kern sys Message-ID: <20160801230222.GA24559@dft-labs.eu> References: <201608012148.u71LmbaA003739@repo.freebsd.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <201608012148.u71LmbaA003739@repo.freebsd.org> User-Agent: Mutt/1.5.21 (2010-09-15) X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.22 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 01 Aug 2016 23:02:28 -0000 On Mon, Aug 01, 2016 at 09:48:37PM +0000, Mateusz Guzik wrote: > Implement trivial backoff for locking primitives. > [..] > For simplicity, this first thouch implementation only modifies spinning > loops where the lock owner is running. spin mutexes and thread lock were > not modified. > What maybe I should have noted in the commit message. This is a perfectly MFCable and much needed band-aid, which will later be extended to cover the rest of the loops and other primitives. There are several approaches which give better results but are also significantly more complicated to implement. Until a suitable approach is worked out and tested, the work here hopefully helps enough. -- Mateusz Guzik