From owner-freebsd-hackers@freebsd.org Fri Mar 18 18:49:20 2016 Return-Path: Delivered-To: freebsd-hackers@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 890A9AD5D41 for ; Fri, 18 Mar 2016 18:49:20 +0000 (UTC) (envelope-from rysto32@gmail.com) Received: from mail-io0-x229.google.com (mail-io0-x229.google.com [IPv6:2607:f8b0:4001:c06::229]) (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 33264FE2; Fri, 18 Mar 2016 18:49:20 +0000 (UTC) (envelope-from rysto32@gmail.com) Received: by mail-io0-x229.google.com with SMTP id v123so37458109ioe.0; Fri, 18 Mar 2016 11:49:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc; bh=AoF8jD67/vh0nsS7HUDCyZWYAb8r7DIse4lqrfEDTRc=; b=CEbMUdrO5CxPRtmNWLfgpvq9h4HKtFohDY4EDVLf+WoIwYKOLkgUvJ0NmBJzHYJlPX ohZMQRDqhUflQbY49ct50xXB5so/hWtlay2MzNo4HTX9jSBNH7c5NMlCBlraXj54Jtwh gN9u95ZX5iD4AX3Ve8gllpqLTvccldw8OacG7I1Oq9qXAQ4Rnv5KC4AZs0wlWnK51G3J ZYJRwz2pA9gRpLdW3ANu96HwVT839Ow1mV6NOZy4RwOULl5kL9xUfn02OTh1YTJgYt6P Nsvn83i9aR48hOkvNdNpclgqYutiW28k18zGFaaXoZsug0IDvdrjinE2pJYZzoxAO759 f4Dw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc; bh=AoF8jD67/vh0nsS7HUDCyZWYAb8r7DIse4lqrfEDTRc=; b=PF7dzzH5N714ODVKQomhRFOsKYf1x+YaykJjJiO71Oh2hJFICpM7N7ej+YyIfvHJXj cKhzoOE3/6AjYBtQ0aK927cwQPVlenvW7rd9qJwSA/qe6FtGihSBFSPhABB07zKgrkI0 yKDfg+5kO1DNyFSYHwAVMsgwiOc5VOa6SXn0uk+d58UczuUtKWoQDdkPK1/pd5V+zr2r L/f899B9oLCKtp/+mZuLlo7PGNL9NYrbrAEIIaktxkHLh36fZ3nxW5t9RtvcI+qZtBJu wK8Exrd0Ot0WN3UQjQGaiIHE+DZmTqyoAe/1rPdsr4z38vKa2YDIg7WMDOPx5LWbiFel PPKA== X-Gm-Message-State: AD7BkJJGBI+LC7yS9IJdq9VfpJ4BPzQPQExzJS+6kO/IlfTSx7GkFvrHSDzJTWwbucMHLp4HNQZslaLpO3GXUg== MIME-Version: 1.0 X-Received: by 10.107.159.137 with SMTP id i131mr8269871ioe.29.1458326959633; Fri, 18 Mar 2016 11:49:19 -0700 (PDT) Received: by 10.107.6.32 with HTTP; Fri, 18 Mar 2016 11:49:19 -0700 (PDT) In-Reply-To: <3277812.DVsZx4uMun@ralph.baldwin.cx> References: <8403291.NqUNo0Qq5W@ralph.baldwin.cx> <3277812.DVsZx4uMun@ralph.baldwin.cx> Date: Fri, 18 Mar 2016 14:49:19 -0400 Message-ID: Subject: Re: Peformance issues with r278325 From: Ryan Stone To: John Baldwin Cc: Adrian Chadd , Konstantin Belousov , Stanislav Sedov , "freebsd-hackers@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.21 X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 18 Mar 2016 18:49:20 -0000 On Fri, Mar 18, 2016 at 1:37 PM, John Baldwin wrote: > I think I'll likely just convert it to use a direct > TSC delay loop always in HEAD (assuming that verifies ok in testing as > well). > Couldn't that work incorrectly on VM guests? The tsc is not guaranteed to be monotonic in that environment.