Re: [quicwg/base-drafts] QPACK: Encode Largest Reference modulo MaxEntries (#1763)

Mike Bishop <notifications@github.com> Wed, 26 September 2018 22:22 UTC

Return-Path: <noreply@github.com>
X-Original-To: quic-issues@ietfa.amsl.com
Delivered-To: quic-issues@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 715B3130FE8 for <quic-issues@ietfa.amsl.com>; Wed, 26 Sep 2018 15:22:13 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -3
X-Spam-Level:
X-Spam-Status: No, score=-3 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, GB_SUMOF=5, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=github.com
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id oUNaCWwhcRbW for <quic-issues@ietfa.amsl.com>; Wed, 26 Sep 2018 15:22:10 -0700 (PDT)
Received: from out-1.smtp.github.com (out-1.smtp.github.com [192.30.252.192]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id AFE9D130FA6 for <quic-issues@ietf.org>; Wed, 26 Sep 2018 15:22:10 -0700 (PDT)
Date: Wed, 26 Sep 2018 15:22:09 -0700
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1538000529; bh=xyYxw+8YD/x0Giz/KJZeQS+jVHcPhY7/VBCQaKeZUN4=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=TjFiTIXXRa4LYvNHZu0kh9MBY8+XJ2Wbb7hEVMNCtowBzoBEa20k0halJ6eFkiCHn RZxt2ZM9ICVuU+hZKPUkpxpc5pVAZxNj0RskpRDa+n+tMnLlSsR0GbXu1eXChlZWmd 8ADgesfyCgNAI1rv3W1wmj7F0sRAVhB8wsNwDNZY=
From: Mike Bishop <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4ab69abd71dd45e754d351c88493eaf5424200daa5292cf0000000117c3c89192a169ce1586350b@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/1763/review/159217302@github.com>
In-Reply-To: <quicwg/base-drafts/pull/1763@github.com>
References: <quicwg/base-drafts/pull/1763@github.com>
Subject: Re: [quicwg/base-drafts] QPACK: Encode Largest Reference modulo MaxEntries (#1763)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5bac0691b0d0f_2bc73ffb474d45b8312ce"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: MikeBishop
X-GitHub-Recipient: quic-issues
X-GitHub-Reason: subscribed
X-Auto-Response-Suppress: All
X-GitHub-Recipient-Address: quic-issues@ietf.org
Archived-At: <https://mailarchive.ietf.org/arch/msg/quic-issues/X-2fV23M7gfF1bhOV8CIiFSf1VU>
X-BeenThere: quic-issues@ietf.org
X-Mailman-Version: 2.1.29
List-Id: Notification list for GitHub issues related to the QUIC WG <quic-issues.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/quic-issues/>
List-Post: <mailto:quic-issues@ietf.org>
List-Help: <mailto:quic-issues-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/quic-issues>, <mailto:quic-issues-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 26 Sep 2018 22:22:17 -0000

MikeBishop approved this pull request.



> @@ -149,7 +149,9 @@ peer's SETTINGS frame.
 
 Before a new entry is added to the dynamic table, entries are evicted from the
 end of the dynamic table until the size of the dynamic table is less than or
-equal to (maximum size - new entry size) or until the table is empty.
+equal to (maximum size - new entry size) or until the table is empty. The
+encoder MUST not evict a dynamic table entry unless it has first been

MUST NOT

> +### Calculating Table Size
+
+The size of the dynamic table is the sum of the size of its entries.
+
+The size of an entry is the sum of its name's length in octets (as defined in
+{{string-literals}}), its value's length in octets, and 32.
+
+The size of an entry is calculated using the length of its name and value
+without any Huffman encoding applied.
+
+`MaxEntries` is the maximum number of entries that the dynamic table can have.
+The smallest entry has empty name and value strings and has the size of 32.
+The MaxEntries is calculated as
+
+~~~
+   MaxEntries = floor( MaxTableSize / 32 )

As we discussed, I'm unconvinced that this should be `floor` instead of `ceil`.  This will generally not matter much in the real world, but could break in edge cases.

-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/quicwg/base-drafts/pull/1763#pullrequestreview-159217302