From owner-freebsd-questions@freebsd.org Thu Apr 7 17:35:43 2016 Return-Path: Delivered-To: freebsd-questions@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 55ED6B08CBD for ; Thu, 7 Apr 2016 17:35:43 +0000 (UTC) (envelope-from vrwmiller@gmail.com) Received: from mail-oi0-x22f.google.com (mail-oi0-x22f.google.com [IPv6:2607:f8b0:4003:c06::22f]) (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 1B9DA13A7; Thu, 7 Apr 2016 17:35:43 +0000 (UTC) (envelope-from vrwmiller@gmail.com) Received: by mail-oi0-x22f.google.com with SMTP id w85so107931419oiw.0; Thu, 07 Apr 2016 10:35:43 -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; bh=lCBB6LycDdjji2zBhvVMUhumxis1HkRM3trXhuozt78=; b=I+BsKkEH8ZLsIN+aCd6tjc/zOcy5d1yvxKyrTmH4VyMp33OyeHWyZkxuMJpXS+ERx0 zVfyx9eLHE4/YcwXt3kZVWBXYtR8AKnINXaktkQoNMQm4EcNKKPLZGBHKxQw3sxmDg0R /veS+BhLMrcrd499i6gOUqkwMwBWeArmTODNlwadCF78+dI5fM6TuwcYsLmUw9MMjk9S qfxQM35/p3tdt1NHqalaZqSteRJGxOOSzx9aFU/wBzjpn0RU0HQmvuQkoUgq5DY6bmSL IUQ9ch/ODeaA4DzxyIuAZ12YfBeQ0vv8qHuzkyFSjOFE37tW1ztnnfWwY2qlocfpA8F9 VbPg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:sender:in-reply-to:references:date :message-id:subject:from:to:cc; bh=lCBB6LycDdjji2zBhvVMUhumxis1HkRM3trXhuozt78=; b=UOwwfv2VFHWiyUKemGX0H4vb2CX66PUt6qxqDijg42+CpPQr3Qmt86G0VKfXayteLK teniCM+uxxW7c6FLfUKDzQPDwyT0hVJMi8aPuNB3X8uQxuc+di9Ye7ZwLz4OFvftVG9q 3ed8nFKIgPurLiAsYGGouujOzVVp7iIME0ecRCEsQa7SEhw7cgkm4MrMbo5McOBf+tUr 2PbdNg3Jou1x4XLUMoCTD6zZhqPIcz+Mo+iAErGqHsNpTIwEEwvES3WjLNqFB2NUiywe eFO+7m7LMDcMYYty8T8onw+i3ssbLpVxHAXvjFR1gBGjCLMLHoQHszlxExP3obvx7R0O p4yQ== X-Gm-Message-State: AD7BkJLghHc+qnZu33QjlTd3k6VJGs0qR+0RgGOuMHg6/y5qwzjA9mJdMW0yiUrUsf1KVVdBZYgsK6cn5rLicw== MIME-Version: 1.0 X-Received: by 10.157.39.193 with SMTP id c59mr2344130otb.111.1460050542352; Thu, 07 Apr 2016 10:35:42 -0700 (PDT) Sender: vrwmiller@gmail.com Received: by 10.202.198.18 with HTTP; Thu, 7 Apr 2016 10:35:42 -0700 (PDT) In-Reply-To: <5706918A.2060502@FreeBSD.org> References: <5706918A.2060502@FreeBSD.org> Date: Thu, 7 Apr 2016 13:35:42 -0400 X-Google-Sender-Auth: g-MRfhSlLeyOHG4Z9V9DYDGRXAA Message-ID: Subject: Re: AIO in 10.0-RELEASE From: Rick Miller To: Matthew Seaman Cc: FreeBSD Questions Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.21 X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 07 Apr 2016 17:35:43 -0000 On Thu, Apr 7, 2016 at 12:57 PM, Matthew Seaman wrote: > On 2016/04/07 16:25, Rick Miller wrote: > > Hi all, > > > > A user has been implementing AIO features in an application. They assert > > that, despite aio(4) stating that it is enabled either statically (with > > VFS_AIO in the kernel config) or dynamically (kldload), in their > > development environment there was no requirement for either of these > > methods of enabling AIO. My google-foo is failing me when it comes to > > FreeBSD's AIO. > > > > This question defies logic, but is it possible that AIO works by default > in > > earlier versions of 10.0 and not in more recent version of 10.0 without > any > > local system changes? > > > > You asked a pretty similar question last month, where one of the replies > pointed you to this in the UPDATING file: > > 20160301: > The AIO subsystem is now a standard part of the kernel. The > VFS_AIO kernel option and aio.ko kernel module have been removed. > Due to stability concerns, asynchronous I/O requests are only > permitted on sockets and raw disks by default. To enable > asynchronous I/O requests on all file types, set the > vfs.aio.enable_unsafe sysctl to a non-zero value. > > In fact, that change was *after* 10.3 was branched, so 10.3-RELEASE > should behave the same as 10.2 and earlier as far as AIO is concerned. > > > https://svnweb.freebsd.org/base/releng/10.3/UPDATING?revision=297262&view=markup > > As far as I can tell from the manual, calls to aio_read(2) and similar > functions should generate an ENOSYS error code, unless your system > kernel has the aio module ceither compiled in or loaded. Which runs > counter to your user's experience. > > I suggest asking on freebsd-hackers@... as you're more likely to come to > the attention of the responsible developers there. > Thanks, Matthew...it is that UPDATING entry that caused the engineer to perform additional testing. The engineer's description of his observances during testing explicitly called out that AIO was seemingly enabled in the development environment despite not being enabled via kldload. I'm confident that AIO is not enabled in the kernel after verifying VFS_AIO was not specified in the kernel config of the compiled distribution. Thus the question...I'll check freebsd-hackers. Appreciate it. -- Take care Rick Miller