From owner-svn-src-all@freebsd.org Fri Jun 8 03:07:10 2018 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id B3D9E100D7D8; Fri, 8 Jun 2018 03:07:10 +0000 (UTC) (envelope-from mat.macy@gmail.com) Received: from mail-it0-x243.google.com (mail-it0-x243.google.com [IPv6:2607:f8b0:4001:c0b::243]) (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 2A9236E77A; Fri, 8 Jun 2018 03:07:10 +0000 (UTC) (envelope-from mat.macy@gmail.com) Received: by mail-it0-x243.google.com with SMTP id 76-v6so625210itx.4; Thu, 07 Jun 2018 20:07:10 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=0gsHOZzkRMaphNKVpokIi0IvIB2k+j9gCdlX5geVTik=; b=J69vgGQiG9fiUgzPZ2QfxlQ2T2vicCMBqVfmR9/BZnzmE4dwygEvYTG5yezrOKxiFl xu1PRIJtfFNXypq3B/mUlC/4o0h7e0AJO4GXoXa4Jj1EOwGUo8jCPXYOCfq1NMwUnEzz REkViyyrQthFjl71Yk2NcX6Kok7AE6CkO6dD+kwXri8RbfDjJTA2m22U9Bf7hMJVgPdv plZJ0Mou1GmV5fzikmJqT5E2KXwM7k0qZU+5V86Rqs4+NGwVRSSNOmqD/q9+I+jdbaAj Va3ph+Y8xwEZXrzxZMs2X0AJ3OR0yH8+d0X5XoDLPsXCFmQ0Nn4ZNstdMgxS6v+A7wlP smhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=0gsHOZzkRMaphNKVpokIi0IvIB2k+j9gCdlX5geVTik=; b=by6oBqCdiqKZZmW34/yrEJ/VzB6ee5x5ZHLFZVYKKHAZoWErGXEUTeDT4a7JjDX7X3 vlC3IU/a6rjciXVy9bFARGDQyK/GSg95qgLOD0U3EVc1CFQ0v6Op52GN/nSSk4jbLllU mF9ijfXuY3hOVnT5Ps7fHKW/6ck30mEU5uNIwMbSGQ3J+oYdv5OYx9S57oOSYpOgzQdJ 1N7m7+IAoyJBgBYtGg/PuAqPESCmQkqbe1J1GG12dM4mN5FokGefE+nDhEKxmHb/i3ts S/3nX2pQob8kw65NFSKEAZFWAIfIXsENVyBg/TsVhL7T0GIkXI6ic7xgF2J9EoKCyhPh rnOQ== X-Gm-Message-State: APt69E0AJIX7nMHJfH3IGRxTrhv0pmqT9tnuQoa08mP2ZlXtebYKUOIl O4xJ+ra88wQe8NZjORT0l98HnzLhEoNIHlkhgVED4Q== X-Google-Smtp-Source: ADUXVKJnwVB7RsrOcxrg2BtDftZjXN+mdjRoEK6KCvQF2/f38LgcGiXjE4W4P3yRvsT6rcdBTZv4ACaNVXa2eihQIlA= X-Received: by 2002:a24:2745:: with SMTP id g66-v6mr244615ita.77.1528427229428; Thu, 07 Jun 2018 20:07:09 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a02:8cd:0:0:0:0:0 with HTTP; Thu, 7 Jun 2018 20:07:08 -0700 (PDT) In-Reply-To: <20180608015740.GD62424@strugglingcoder.info> References: <201806071818.w57IIENp080093@repo.freebsd.org> <20180607220121.GC62424@strugglingcoder.info> <40CCC8B4-5667-4D4B-A4B4-7AD5779FE011@netflix.com> <20180608015740.GD62424@strugglingcoder.info> From: Matthew Macy Date: Thu, 7 Jun 2018 20:07:08 -0700 Message-ID: Subject: Re: svn commit: r334804 - in head/sys: kern modules/tcp modules/tcp/rack netinet netinet/tcp_stacks sys To: hiren panchasara Cc: Randall Stewart , Randall Ray Stewart , src-committers , svn-src-all@freebsd.org, svn-src-head@freebsd.org Content-Type: text/plain; charset="UTF-8" X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.26 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: Fri, 08 Jun 2018 03:07:10 -0000 > > Okay. I believe there might be situations where we may want to still > keep the 'default' stack alive. I know Windows doesn't yet use RACK when > rtt is lesser than 10ms (or something like that), as an example. > Is there any reason RACK wouldn't work for tracking 10us RTTs? If we know we know the peer doesn't do delack or have enough data in flight and the other stack doesn't have broken LRO, could we just use this in lieu of high resolution timestamps? -M