From owner-freebsd-current@FreeBSD.ORG Sun Sep 1 23:45:50 2013 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 ESMTP id 5905C16A; Sun, 1 Sep 2013 23:45:50 +0000 (UTC) (envelope-from davide.italiano@gmail.com) Received: from mail-vb0-x236.google.com (mail-vb0-x236.google.com [IPv6:2607:f8b0:400c:c02::236]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id 037872E85; Sun, 1 Sep 2013 23:45:49 +0000 (UTC) Received: by mail-vb0-f54.google.com with SMTP id q14so2647147vbe.13 for ; Sun, 01 Sep 2013 16:45:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=A801uS7a9SH+yKgHavyZO+SDNZqTiYO7xjJj0sjmHnM=; b=pESVEG6Xm3M5MKtdKW09uX4xYRgLT3ARwMcyy/1HR//VuAspsjZjWcnZmsEOhp3qZb MDzFEfHUzFvwI02F6P3SSVnt+nby136P/sH3lZtv+AFEEdZGzd8C9G1fAX2jL5S4B37D M62F8/mihaP5gfDJXKFZcLpXEtnD/m8Qhr0eq5xYc9WOKWddiN1nA9ug/dxL7SkCTLNw ZjdXBAnT+o8dBYsoUFoE5INOtML8O4IqWrZdBujUW9GKQfpYuFFotM8uGsBoutWj//EW 8CmV1M9hiiWMj3odmv9olhRBUYe84+2xrOIMkbd6ccTOUXIgkRonMAweosabh3S6fWOo s13w== MIME-Version: 1.0 X-Received: by 10.220.46.72 with SMTP id i8mr20459693vcf.10.1378079149091; Sun, 01 Sep 2013 16:45:49 -0700 (PDT) Sender: davide.italiano@gmail.com Received: by 10.220.65.132 with HTTP; Sun, 1 Sep 2013 16:45:49 -0700 (PDT) In-Reply-To: References: <201308221408.08203.jhb@freebsd.org> <201308230945.28701.jhb@freebsd.org> Date: Mon, 2 Sep 2013 01:45:49 +0200 X-Google-Sender-Auth: ztgh1TL5Y3bHrC-ruFGtOvT8MWA Message-ID: Subject: Re: Question about socket timeouts From: Davide Italiano To: Vitja Makarov Content-Type: text/plain; charset=ISO-8859-1 Cc: freebsd-current X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.14 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: Sun, 01 Sep 2013 23:45:50 -0000 On Tue, Aug 27, 2013 at 7:10 AM, Vitja Makarov wrote: >> On Fri, Aug 23, 2013 at 7:04 AM, Vitja Makarov wrote: >>> 2013/8/23 Davide Italiano : >>> >>> I think that for socket's timeouts it's ok to have a HZ-precision. It >>> would be much more important to implement high-precision timeouts for >>> select() and friends, if it's not done yet (sorry I'm running 9.1). >>> >> >> JFYI, select()/usleep()/etc... are all fine grained right now in HEAD. >> > > That's cool! Does that mean that FreeBSD 10 would be a tickless system? > > -- > vitja. FreeBSD will have a tickless callout(9) subsystem. There are still some kernel subsystems that depends on hardclock() even if the long term goal is that of moving away from it (when/if possible). A notable example is SCHED_ULE code which depends on hardclock() (sched_tick()) but it could be optimized to skip some calls even though CPU is active. -- Davide "There are no solved problems; there are only problems that are more or less solved" -- Henri Poincare