From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.6 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD shortcircuit=no autolearn=ham autolearn_force=no version=3.4.0 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 2BC9D2018F for ; Tue, 19 Jul 2016 19:53:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751708AbcGSTxw (ORCPT ); Tue, 19 Jul 2016 15:53:52 -0400 Received: from mail-pa0-f65.google.com ([209.85.220.65]:36123 "EHLO mail-pa0-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750998AbcGSTxv (ORCPT ); Tue, 19 Jul 2016 15:53:51 -0400 Received: by mail-pa0-f65.google.com with SMTP id ez1so1847150pab.3 for ; Tue, 19 Jul 2016 12:53:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=8AHHj17uXvV6TDWGgN8vSD5ft84GRXKk2KwRj//tfg8=; b=hpzap+Hx+0iQwVtM55NpGOqo1FI+TUPCx+tKJCL27bV2Ok+z8NgpyXN+/uGvZ06BYM 1dKQY8LAiU0l4fwyb7LRrrIXBAxKfPq1YNX4XXZZwE1wDnovBT6Hf3jyPrxYwi1btnsH ZKrK87HpYcJHj1jwFG10lHktIIqBdLU/4dMMqrGJArMe7h4ODKUMbwOU3jGbXacUSt12 9G0nO8UmsPJZL6Cyvp64C1prnQqClug86wk0TBxzdJm+/oANZETNBijdUKcJ5BMh4scc +o4gslWXtDZ1iKlNR4G1JIDz2QjzImD/m86knG/nkEDIJJxWT4dO4STemNe7eAvrD6C2 Fu6A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=8AHHj17uXvV6TDWGgN8vSD5ft84GRXKk2KwRj//tfg8=; b=XKYz0jGlA7vQZo2TxQ/FyV23sBcZ6hSeLCpUPbglA2Q3TShTEIBzWAqOXZsYVzN3Fk gdyKB07D2c0MAW/txMS3GFQUM8z4pEFShCcATgrOAvJVQ4YaK5fcqfg6x54ZhfvCVKmh ukJ0OL3x2OHLgDwjOSmNns3mDZa8ZTQOq0JCYFPVo7tc/zzhgjywP9ssw6VBZ7pIDqZy O+1opR2BiOhA56affNui1FAgHons39Czvv/AhMw8IL/zXDmExsdm1A0bZN+nWOXMtN+3 3fZ1WHcFqyDEWWrcDdJqk4XkW0VX2DqLOIFPQFukg6UxH66L6lyBh+W74E6GOG7kummR gi0A== X-Gm-Message-State: ALyK8tKBgUny5d0lYs/8JQ5mFzSoyen4BhXrnhBtSgFufchziaN3vOcOrEz/F7bhYhHGLw== X-Received: by 10.66.254.102 with SMTP id ah6mr69311595pad.59.1468958030569; Tue, 19 Jul 2016 12:53:50 -0700 (PDT) Received: from google.com ([2620:0:1000:5b10:1490:ebec:2572:a3af]) by smtp.gmail.com with ESMTPSA id u72sm464383pfa.31.2016.07.19.12.53.49 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Tue, 19 Jul 2016 12:53:49 -0700 (PDT) Date: Tue, 19 Jul 2016 12:53:47 -0700 From: Jonathan Nieder To: Junio C Hamano Cc: Jonathan Tan , Stefan Beller , "git@vger.kernel.org" Subject: Re: [PATCH v2] fetch-pack: grow stateless RPC windows exponentially Message-ID: <20160719195347.GF29326@google.com> References: <1468880498-30235-1-git-send-email-jonathantanmy@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Junio C Hamano wrote: > Even if it is conservative, I wonder if it is truly a good idea to > make it exponentially grow forever from that point of view. Would > it give essentially the same result to you if we discard the patch > in question and just raise LARGE_FLUSH to 10k instead? I don't think it would be essentially the same result. As discussed before, unlike the bidi (ssh:// and git:// protocols) case, linear growth is expensive in the stateless-rpc (https://) case --- each round of negotiation requires re-sending the existing 'have's and requires the peer repeatedly processing this increasingly large list of 'have's. For comparison, in the bidi case, linear growth of next_flush means sending a bounded number of 'have's per round and is quite sensible. In the stateless-rpc case, linear growth means getting a bounded number of 'have's worth of benefit (new 'have's) in each round, in exchange for a linearly increasing cost (existing 'have's). That is a high cost for limited benefit. Exponential growth is a better deal. Jonathan