Return-Path: 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 8BA3D12DA27 for ; Fri, 1 Jun 2018 13:50:41 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -8.01 X-Spam-Level: X-Spam-Status: No, score=-8.01 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001, T_DKIMWL_WL_HIGH=-0.01] 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 p_FgnsjA8shN for ; Fri, 1 Jun 2018 13:50:39 -0700 (PDT) Received: from out-7.smtp.github.com (out-7.smtp.github.com [192.30.252.198]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id C6E9C12D9FE for ; Fri, 1 Jun 2018 13:50:39 -0700 (PDT) Date: Fri, 01 Jun 2018 13:50:39 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1527886239; bh=VHJj3frIKZlgxLW2sma8jgbnkGLlHn4qbZycYSEIbWQ=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=nLhCe9TAR84fhIU0weMhcBeIfhhQkWHx+jwwlQsWEQqrIps0kKcOLC79hLYlTASik kRpPN4u4IfkKuRvcdiinC178TzhPX2xy13+ma/IyyxYo8g0kUhXFNl/QQBLZJHJc8m dvNgmY9HG6TE7wBhzH3oCvYnMueuHlDmCf7VNP8Q= From: afrind Reply-To: quicwg/base-drafts To: quicwg/base-drafts Cc: Subscribed Message-ID: In-Reply-To: References: Subject: Re: [quicwg/base-drafts] Implicit acknowledgment via header block acknowledgment (#1399) Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="--==_mimepart_5b11b19f2e7bf_9913fe65ec26f80980e6"; charset=UTF-8 Content-Transfer-Encoding: 7bit Precedence: list X-GitHub-Sender: afrind X-GitHub-Recipient: quic-issues X-GitHub-Reason: subscribed X-Auto-Response-Suppress: All X-GitHub-Recipient-Address: quic-issues@ietf.org Archived-At: X-BeenThere: quic-issues@ietf.org X-Mailman-Version: 2.1.22 List-Id: Notification list for GitHub issues related to the QUIC WG List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 01 Jun 2018 20:50:42 -0000 ----==_mimepart_5b11b19f2e7bf_9913fe65ec26f80980e6 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit afrind commented on this pull request. > @@ -491,7 +491,14 @@ instruction begins with the '1' one-bit pattern. The instruction specifies the total number of dynamic table inserts and duplications since the last Table State Synchronize, encoded as a 7-bit prefix integer. The encoder uses this value to determine which table entries are vulnerable to head-of-line blocking. -A decoder MAY coalesce multiple synchronization updates into a single update. + +A decoder MAY coalesce multiple synchronization updates into a single update. A +decoder MAY rely on Header Acknowledgement instructions to indirectly +acknowledge changes to the dynamic table. Relying on Header Acknowledgment +instructions exclusively leads to blocking if the encoder waits for an entry to I don't think it would lead to blocking, but it would lead to never using the dynamic table? > @@ -523,6 +530,12 @@ blocks within a stream have been fully processed. ~~~~~~~~~~ {:#fig-header-ack title="Header Acknowledgement"} +An encoder MUST treat receipt of a Header Acknowledgment as also acknowledging +any dynamic table entries that the header block referenced. That is, this +instruction is also processed as a Table Size Synchronize instruction with a +value matching the Largest Reference of the corresponding header block. You mean TSS will be incremental from the largest acknowledged largest reference or most recent TSS? > @@ -491,7 +491,14 @@ instruction begins with the '1' one-bit pattern. The instruction specifies the total number of dynamic table inserts and duplications since the last Table State Synchronize, encoded as a 7-bit prefix integer. The encoder uses this value to determine which table entries are vulnerable to head-of-line blocking. -A decoder MAY coalesce multiple synchronization updates into a single update. + +A decoder MAY coalesce multiple synchronization updates into a single update. A +decoder MAY rely on Header Acknowledgement instructions to indirectly +acknowledge changes to the dynamic table. Relying on Header Acknowledgment +instructions exclusively leads to blocking if the encoder waits for an entry to +be acknowledged before using it. This happens if the encoder wants to avoid the +risk of blocking at the decoder, or the decoder sets the +SETTINGS_QPACK_BLOCKED_STREAMS lower than the number of active streams. I had to read this many times to figure out what you are saying - you are explaining why the encoder might be waiting for acknowledgement before using the headers in the dynamic table. I think it might be more clear if you change the second bit to something like "... or the encoder has already reached the decoder's limit for blocked streams". -- 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/1399#pullrequestreview-125305701 ----==_mimepart_5b11b19f2e7bf_9913fe65ec26f80980e6 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit

@afrind commented on this pull request.

In draft-ietf-quic-qpack.md:

> @@ -491,7 +491,14 @@ instruction begins with the '1' one-bit pattern. The instruction specifies the
 total number of dynamic table inserts and duplications since the last Table
 State Synchronize, encoded as a 7-bit prefix integer.  The encoder uses this
 value to determine which table entries are vulnerable to head-of-line blocking.
-A decoder MAY coalesce multiple synchronization updates into a single update.
+
+A decoder MAY coalesce multiple synchronization updates into a single update.  A
+decoder MAY rely on Header Acknowledgement instructions to indirectly
+acknowledge changes to the dynamic table.  Relying on Header Acknowledgment
+instructions exclusively leads to blocking if the encoder waits for an entry to

I don't think it would lead to blocking, but it would lead to never using the dynamic table?

In draft-ietf-quic-qpack.md:

> @@ -523,6 +530,12 @@ blocks within a stream have been fully processed.
 ~~~~~~~~~~
 {:#fig-header-ack title="Header Acknowledgement"}
 
+An encoder MUST treat receipt of a Header Acknowledgment as also acknowledging
+any dynamic table entries that the header block referenced.  That is, this
+instruction is also processed as a Table Size Synchronize instruction with a
+value matching the Largest Reference of the corresponding header block.

You mean TSS will be incremental from the largest acknowledged largest reference or most recent TSS?

In draft-ietf-quic-qpack.md:

> @@ -491,7 +491,14 @@ instruction begins with the '1' one-bit pattern. The instruction specifies the
 total number of dynamic table inserts and duplications since the last Table
 State Synchronize, encoded as a 7-bit prefix integer.  The encoder uses this
 value to determine which table entries are vulnerable to head-of-line blocking.
-A decoder MAY coalesce multiple synchronization updates into a single update.
+
+A decoder MAY coalesce multiple synchronization updates into a single update.  A
+decoder MAY rely on Header Acknowledgement instructions to indirectly
+acknowledge changes to the dynamic table.  Relying on Header Acknowledgment
+instructions exclusively leads to blocking if the encoder waits for an entry to
+be acknowledged before using it.  This happens if the encoder wants to avoid the
+risk of blocking at the decoder, or the decoder sets the
+SETTINGS_QPACK_BLOCKED_STREAMS lower than the number of active streams.

I had to read this many times to figure out what you are saying - you are explaining why the encoder might be waiting for acknowledgement before using the headers in the dynamic table. I think it might be more clear if you change the second bit to something like

"... or the encoder has already reached the decoder's limit for blocked streams".

—
You are receiving this because you are subscribed to this thread.
Reply to this email directly, view it on GitHub, or mute the thread.

----==_mimepart_5b11b19f2e7bf_9913fe65ec26f80980e6--