From owner-freebsd-net@FreeBSD.ORG Wed Apr 22 04:50:51 2015 Return-Path: Delivered-To: freebsd-net@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 2081C810; Wed, 22 Apr 2015 04:50:51 +0000 (UTC) Received: from mail-ig0-x22b.google.com (mail-ig0-x22b.google.com [IPv6:2607:f8b0:4001:c05::22b]) (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 E061C1B91; Wed, 22 Apr 2015 04:50:50 +0000 (UTC) Received: by igblo3 with SMTP id lo3so32822867igb.0; Tue, 21 Apr 2015 21:50:50 -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=88b2NSyQA/XqCeqh9ivmQDx0aSr2FsCTH3l5Gx9NUvY=; b=oo+kkcMiwtETtdhOeREKpxyZGb0xGUenSVajcAg9mPuXJGYBMPr9ImlINCsi3/c0ad y/UssKS7OuWvpnIQFEadksQ8aXdL+kJ3jgTD43IXzfUrQt27D0NsjdBQay2mc/AmX62H feGP9zEJR8lwdiAbUuKULpSTGBk0znKCbVnnBgcMT6OvSaKZgTMySp+LMrULfUkdkliG tMR9fNixEQbhgzsTgyQGbdqy+5WEquNRhjvof4Sisl46F5Bf3M7a/1H6CnC4mk8n96Lc clH3NUP6pSnLqpMIC4o78yaNU6wppqZTNwmv1qHm5FYbxxKqgnVe1GCxLDM6jLNf9PpX GHEQ== MIME-Version: 1.0 X-Received: by 10.107.136.25 with SMTP id k25mr32744056iod.88.1429678250350; Tue, 21 Apr 2015 21:50:50 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.36.17.194 with HTTP; Tue, 21 Apr 2015 21:50:50 -0700 (PDT) In-Reply-To: <553707DF.20305@freebsd.org> References: <553707DF.20305@freebsd.org> Date: Tue, 21 Apr 2015 21:50:50 -0700 X-Google-Sender-Auth: e3jcyHEZfdWvxUAsIzzuO5GnSbg Message-ID: Subject: Re: FYI: TSO results in significant IP ID reuse on short time scales From: Adrian Chadd To: Lawrence Stewart Cc: "freebsd-net@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 22 Apr 2015 04:50:51 -0000 [snip] I bet doing a pre-allocation scheme would be fine. Ie, you make some guess based on payload size and MSS, allocate those, don't worry if you allocate too many. -adrian