From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35D8FC2D0BE for ; Sun, 8 Dec 2019 10:25:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 15F8920663 for ; Sun, 8 Dec 2019 10:25:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726406AbfLHKZ0 (ORCPT ); Sun, 8 Dec 2019 05:25:26 -0500 Received: from mail.phunq.net ([66.183.183.73]:53070 "EHLO phunq.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726202AbfLHKZZ (ORCPT ); Sun, 8 Dec 2019 05:25:25 -0500 Received: from [172.16.1.14] by phunq.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_128_GCM:128) (Exim 4.92.3) (envelope-from ) id 1idtkg-000500-DD; Sun, 08 Dec 2019 02:25:22 -0800 Subject: Re: [RFC] Thing 1: Shardmap fox Ext4 To: "Theodore Y. Ts'o" Cc: linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, OGAWA Hirofumi References: <176a1773-f5ea-e686-ec7b-5f0a46c6f731@phunq.net> <20191127142508.GB5143@mit.edu> <20191128022817.GE22921@mit.edu> From: Daniel Phillips Message-ID: <3b4d380f-cb33-b0fb-2426-67109875ce77@phunq.net> Date: Sun, 8 Dec 2019 02:25:22 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.9.0 MIME-Version: 1.0 In-Reply-To: <20191128022817.GE22921@mit.edu> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-ext4-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-ext4@vger.kernel.org On 2019-11-27 6:28 p.m., Theodore Y. Ts'o wrote: > The use of C++ with templates is presumably one of the "less so" > parts, and it was that which I had in mind when I said, > "reimplementing from scratch". The templates were removed without reimplementing from scratch: https://github.com/danielbot/Shardmap/blob/master/shardmap.h#L88 https://github.com/danielbot/Shardmap/blob/master/shardmap.cc#L82 The duopack/tripack facility, central to Shardmap efficient scalability, are now just ordinary C code that happens to be compiled by a C++ compiler. I think the machine code should be identical to what the templates produced, though I did not verify. This was a strictly mechanical conversion, less error prone than reimplementing from scratch I would think. I expect the rest of the back conversions to be similarly mechanical. Regards, Daniel