Re: [quicwg/base-drafts] Limit CWND increase in slow start (#3232)

Vidhi Goel <notifications@github.com> Mon, 18 November 2019 20:58 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 66A5B12090F for <quic-issues@ietfa.amsl.com>; Mon, 18 Nov 2019 12:58:04 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -8
X-Spam-Level:
X-Spam-Status: No, score=-8 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_32=0.001, HTML_MESSAGE=0.001, MAILING_LIST_MULTI=-1, RCVD_IN_DNSWL_HI=-5, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=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 e0aUDd2zO9t2 for <quic-issues@ietfa.amsl.com>; Mon, 18 Nov 2019 12:58:03 -0800 (PST)
Received: from out-19.smtp.github.com (out-19.smtp.github.com [192.30.252.202]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id E59D6120128 for <quic-issues@ietf.org>; Mon, 18 Nov 2019 12:58:02 -0800 (PST)
Received: from github-lowworker-292e294.va3-iad.github.net (github-lowworker-292e294.va3-iad.github.net [10.48.102.70]) by smtp.github.com (Postfix) with ESMTP id 43A6F521D76 for <quic-issues@ietf.org>; Mon, 18 Nov 2019 12:58:02 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1574110682; bh=SdsAFbByOvHFpN3Ypogw7cZAKKqc+8ZTj/uw2KT8O5o=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=Vw2bFYgEjaFpSk+Xtk1UC4Yg1fMYIEYpqf6kOQi0PSVnAHv+EDGmhO70fySF/AmRd OgoxA9JOcx+A5aQY8Gdqg8f9LSq/XOGuILqGvPCgIy6yVheoISSonk5qaQ9Je884fm ky3PO/Ra2ksAJMOrkM68y2ZNiPA9cWyBObOWd2pw=
Date: Mon, 18 Nov 2019 12:58:02 -0800
From: Vidhi Goel <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+AFTOJKY24LASBVYXCPFDYIV34A4FVEVBNHHB6GTRAA@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/pull/3232/review/318624483@github.com>
In-Reply-To: <quicwg/base-drafts/pull/3232@github.com>
References: <quicwg/base-drafts/pull/3232@github.com>
Subject: Re: [quicwg/base-drafts] Limit CWND increase in slow start (#3232)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5dd305da3411e_25243f83422cd9681010e1"; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Precedence: list
X-GitHub-Sender: goelvidhi
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/b0V-oDvZwDHPSkYmPtZg0fz7sIU>
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: Mon, 18 Nov 2019 20:58:04 -0000

goelvidhi commented on this pull request.



> @@ -1368,7 +1377,15 @@ acked_packet from sent_packets.
        return
      if (congestion_window < ssthresh):
        // Slow start.
-       congestion_window += acked_packet.size
+       if (pacing):
+         congestion_window += acked_packet.size
+       else:
+         // If pacing is not used, limit the increase to
+         // 2*max_datagram_size per ACK as described in
+         // {{?RFC3465}}
+         if (cwnd_increase < 2 * max_datagram_size):
+           cwnd_increase += bytes_acked
+           congestion_window += bytes_acked

The below should work in all cases:
```
if (pacing):
         congestion_window += acked_packet.size
       else:
         // If pacing is not used, limit the increase to
         // 2*max_datagram_size per ACK as described in
         // {{?RFC3465}}
         if (cwnd_increase  < 2 * max_datagram_size):
           old_cwnd_increase = cwnd_increase
           cwnd_increase = min(cwnd_increase + acked_packet.size,
                                            2 * max_datagram_size)
           congestion_window += cwnd_increase - old_cwnd_increase
```


-- 
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/3232#discussion_r347605376