Re: [quicwg/base-drafts] congestion window increase on every ACKed packet could result in bursty sends (#3094)

Vidhi Goel <notifications@github.com> Thu, 17 October 2019 02:10 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 D22AE12011B for <quic-issues@ietfa.amsl.com>; Wed, 16 Oct 2019 19:10:01 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -6.596
X-Spam-Level:
X-Spam-Status: No, score=-6.596 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, 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 sr7FK-CIHtUg for <quic-issues@ietfa.amsl.com>; Wed, 16 Oct 2019 19:10:00 -0700 (PDT)
Received: from out-22.smtp.github.com (out-22.smtp.github.com [192.30.252.205]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 019F6120019 for <quic-issues@ietf.org>; Wed, 16 Oct 2019 19:09:59 -0700 (PDT)
Date: Wed, 16 Oct 2019 19:09:59 -0700
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=github.com; s=pf2014; t=1571278199; bh=ztBRGp2fNC2Gy2+KykG3ORAkLbV+8o28EbMBwigqAok=; h=Date:From:Reply-To:To:Cc:In-Reply-To:References:Subject:List-ID: List-Archive:List-Post:List-Unsubscribe:From; b=Qlp21D+kKGYDBRpNMk3iueejLNTr8lKOr7WrPbdMoo1c5GvMDdjpYpyK1flmg9pFr YwLF7HI3wymhgooqEtExSqhgSG8kkJ/KrkpTxljJf2YzPfpPNCT9spQK+K48YYxsKp cRlS6wtYwimndRfcd11/dCT74hl4H6EUNNlL5BBI=
From: Vidhi Goel <notifications@github.com>
Reply-To: quicwg/base-drafts <reply+AFTOJKZ7WFKLG3G22D65EOF3WUHAPEVBNHHB4PUWF4@reply.github.com>
To: quicwg/base-drafts <base-drafts@noreply.github.com>
Cc: Subscribed <subscribed@noreply.github.com>
Message-ID: <quicwg/base-drafts/issues/3094/542965003@github.com>
In-Reply-To: <quicwg/base-drafts/issues/3094@github.com>
References: <quicwg/base-drafts/issues/3094@github.com>
Subject: Re: [quicwg/base-drafts] congestion window increase on every ACKed packet could result in bursty sends (#3094)
Mime-Version: 1.0
Content-Type: multipart/alternative; boundary="--==_mimepart_5da7cd7743ce5_38153f95efccd96c1046c6"; 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/CJemXkJnXQacLi_mTJBhJ0HzfsA>
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: Thu, 17 Oct 2019 02:10:02 -0000

@junhochoi, I think we need to do 2MSS clamping per ACK received and not per packet acked.

I am thinking that we can remove OnPacketAckedCC and instead do OnAckReceivedCC. Pseudocode change something like this:
```
    OnAckReceived(ack, pn_space):

    Set total_bytes_acked to 0
    for acked_packet in newly_acked_packets:
        total_bytes_acked += acked_packet.size
        OnPacketAcked(acked_packet.packet_number, pn_space)

    OnAckReceivedCC(total_bytes_acked)

OnAckReceivedCC(total_bytes_acked):
    bytes_in_flight -= total_bytes_acked
    if (congestion_window < ssthresh):
         // Slow start.
        congestion_window += min(total_bytes_acked, 2* kMaxDatagramSize)
   else
       congestion_window += kMaxDatagramSize * total_bytes_acked
           / congestion_window
    
```



-- 
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/3094#issuecomment-542965003