Re: [quicwg/base-drafts] RTT sample should be taken only once for each largest_acked (#2569)

Nick Banks <notifications@github.com> Sat, 30 March 2019 22:45 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 76CED12006E for <quic-issues@ietfa.amsl.com>; Sat, 30 Mar 2019 15:45:19 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.598
X-Spam-Level:
X-Spam-Status: No, score=-6.598 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_IMAGE_ONLY_28=1.404, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H2=-0.001, 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 kiM_rfSlIyn6 for <quic-issues@ietfa.amsl.com>; Sat, 30 Mar 2019 15:45:17 -0700 (PDT)
Received: from out-5.smtp.github.com (out-5.smtp.github.com [192.30.252.196]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 96173120004 for <quic-issues@ietf.org>; Sat, 30 Mar 2019 15:45:17 -0700 (PDT)
Date: Sat, 30 Mar 2019 15:45:16 -0700
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1553985916; bh=eux3zbAYEEXuW5jDXbm4RVXAs6HG+Y/2EReIaeAHmYU=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=Cfcdjg3XxZ1TlxUC07NfCugTpjT6PoEP/+BTDx6igghYNdjZcSOU9PH7l6lJEFxzt gv/xe5TJBWDOYJbQQnWqt6qP6hW3nxsL6icHXuDrlu9KY2FQS5u+Pa3T801G6ZmbiN +/zp0Pcb3MJUwx4DVyqvLpv1BIPxFarPQ97wZoeI=
From: Nick Banks <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+0166e4ab19b0b6e404f58ee6b3708f5a486424b8faff1edb92cf0000000118b7b37c92a169ce1978875a@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/issues/2569/478295940@github.com>
In-Reply-To: <quicwg/base-drafts/issues/2569@github.com>
References: <quicwg/base-drafts/issues/2569@github.com>
Subject: Re: [quicwg/base-drafts] RTT sample should be taken only once for each largest_acked (#2569)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5c9ff17c2a3d9_54013f81ed4d45b4160241"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: nibanks
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/KU1PvjyjHbYK211OtcsZcVnpMp8>
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: Sat, 30 Mar 2019 22:45:20 -0000

To be fair, the comment in the pseudo code does say only to update the rtt if it's newly acked:
```
  // If the largest acknowledged is newly acked and
  // ack-eliciting, update the RTT.
  if (sent_packets[pn_space][ack.largest_acked] &&
      sent_packets[pn_space][ack.largest_acked].ack_eliciting):
```
Personally, I'd solve this by always setting `sent_packets[pn_space][#] = null` once it has been acknowledged. Then the pseudo code above would be correct.

-- 
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/issues/2569#issuecomment-478295940