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 543B8120129 for ; Thu, 3 Oct 2019 09:08:40 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -7.898 X-Spam-Level: X-Spam-Status: No, score=-7.898 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_IMAGE_ONLY_32=0.001, 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 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 deyeMfC3yoWh for ; Thu, 3 Oct 2019 09:08:39 -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 D280A1200DF for ; Thu, 3 Oct 2019 09:08:38 -0700 (PDT) Received: from github-lowworker-2ef7ba1.ac4-iad.github.net (github-lowworker-2ef7ba1.ac4-iad.github.net [10.52.16.66]) by smtp.github.com (Postfix) with ESMTP id 3B0339609DE for ; Thu, 3 Oct 2019 09:08:38 -0700 (PDT) Date: Thu, 03 Oct 2019 09:08:38 -0700 From: afrind Reply-To: quicwg/base-drafts To: quicwg/base-drafts Cc: Subscribed Message-ID: In-Reply-To: References: Subject: Re: [quicwg/base-drafts] Boolean blocked streams setting (#3073) Mime-Version: 1.0 Content-Type: multipart/alternative; boundary="--==_mimepart_5d961d062c4ce_2b9d3faff62cd9642334f9"; 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: 2.1.29 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: Thu, 03 Oct 2019 16:08:40 -0000 ----==_mimepart_5d961d062c4ce_2b9d3faff62cd9642334f9 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit I didn't find the numeric setting significantly more complicated to implement than a boolean setting. The [diff](https://github.com/facebook/proxygen/commit/09cb1304fb52149b7343f9f22d44ed3efa130840#diff-cde3cb3125e1e0b319d8264cb67c7de8) that converted it from a boolean to a number touched about 25 lines of code in the encoder. I find that the bigger complexity comes from having the implementation allow both blocking and non-blocking. proxygen uses the count, which is incremented when sending a header block with a potentially blocking reference and decremented on acks and cancellations. I don't decrement the count on Insert Count Increment, and I count multiple potentially blocking blocks on the same stream individually. Both of these make the implementation more conservative than necessary, but the code is pretty simple. As for a use case, lately I've been working with our RPC over HTTP stack, which generally sets the stream limit in the 100k range. There's more of a case to be made for keeping the QPACK blocking limit lower than the stream limit when you've got a bonkers stream limit. When the stream limit is 100 or something else webish, 10 vs. 50 vs 100 doesn't seem super meaningful. -- 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/3073#issuecomment-538012823 ----==_mimepart_5d961d062c4ce_2b9d3faff62cd9642334f9 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: 7bit

I didn't find the numeric setting significantly more complicated to implement than a boolean setting. The diff that converted it from a boolean to a number touched about 25 lines of code in the encoder. I find that the bigger complexity comes from having the implementation allow both blocking and non-blocking.

proxygen uses the count, which is incremented when sending a header block with a potentially blocking reference and decremented on acks and cancellations. I don't decrement the count on Insert Count Increment, and I count multiple potentially blocking blocks on the same stream individually. Both of these make the implementation more conservative than necessary, but the code is pretty simple.

As for a use case, lately I've been working with our RPC over HTTP stack, which generally sets the stream limit in the 100k range. There's more of a case to be made for keeping the QPACK blocking limit lower than the stream limit when you've got a bonkers stream limit. When the stream limit is 100 or something else webish, 10 vs. 50 vs 100 doesn't seem super meaningful.

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