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=-2.8 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,T_RP_MATCHES_RCVD shortcircuit=no autolearn=no 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 1F30A1F42D for ; Sat, 31 Mar 2018 04:11:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750776AbeCaELC (ORCPT ); Sat, 31 Mar 2018 00:11:02 -0400 Received: from mail-ot0-f196.google.com ([74.125.82.196]:38762 "EHLO mail-ot0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750718AbeCaELB (ORCPT ); Sat, 31 Mar 2018 00:11:01 -0400 Received: by mail-ot0-f196.google.com with SMTP id o9-v6so11119303otj.5 for ; Fri, 30 Mar 2018 21:11:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=rlvSjL9oAg1rjEX3h0OdUqzSy7W1qpsm8GSwkSjdBds=; b=kPHMlf/7x3Fcz4DGYRaLVYJu+b4kRTIDUvEYfYKEm9EDk4MPmUbdZEdzMxL2HpgAx/ lx3ykCtjphfOFlaLbR3/Qn819x4Xrdg6L3oHnUyXd/wI6GfLI+19i/uU448rqdKi52Ny C1E+UE+dso4EXdlheSKDwxYGlWVNehd0FhgJm+wLeSqn5vT6DC6GS1H9c6Mr1YA5VJYs 1UUPO0N/tcwZ1WkxbiamG7JLGgr/ie6GiSwtFxxNqXB9XniIZq+RZIJ/wy9Fn+/8qKyl jgT8/mydAW8anXAh2a8mH07xOECG1iHI+btLNNh5qS4kETF645Y9NgFXc3sPc3Mqp88J bWBw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=rlvSjL9oAg1rjEX3h0OdUqzSy7W1qpsm8GSwkSjdBds=; b=A8RStSO6NE5jYcHuPSCEhT2amY+aoiQNfg0VFiR87Os3hBfEJpD9EbuQQ6ZuXr+OOZ EgKO/cvF1NtHP8bzuN5lauLeR7ipJKYzauCziIpSfZ+JUb2DjJYzEiNiqzMwiybBnoL7 2ZnZ7wAjMJxt2XZ1CGR89PYM8xomS5beTOAbE9FhQsQFCGACZgWto9ODeTZZk/rdcSF7 6d/bcE0zXkCXQxvubEiv3YbAZ9rfP+ePzXq7sr0+bMA2eyinE1nRvCAwe4x88hPMEODB 2wIF9UEzdlOWuA1uNp3lgUkgNY6+nBBka3CtMfMsXv7ajb9w808G4UrR6l07piy1kqtV mFsg== X-Gm-Message-State: ALQs6tCMUtiC7wbgMw2GKWTmv4YSYGBXOtp2F2V23Te+iGO/gdnm90ty LH6ZqvXJ9PuQRyRQxrKqoLek6eC8GrkX8CWsxok= X-Google-Smtp-Source: AIpwx4+2/8vajKPzLY1YfQTvCS8m2hi55Z2re8lcQqLp9abd2xP2rWS9+BRtHyNIbW6puPCGTlpmRu6CSQSZnpGF40k= X-Received: by 2002:a9d:e84:: with SMTP id 4-v6mr911588otj.14.1522469461064; Fri, 30 Mar 2018 21:11:01 -0700 (PDT) MIME-Version: 1.0 Received: by 10.74.198.152 with HTTP; Fri, 30 Mar 2018 21:10:30 -0700 (PDT) In-Reply-To: <20180330212656.GK14782@sigill.intra.peff.net> References: <20180318142526.9378-1-pclouds@gmail.com> <20180324063353.24722-1-pclouds@gmail.com> <20180324063353.24722-14-pclouds@gmail.com> <20180330212656.GK14782@sigill.intra.peff.net> From: Duy Nguyen Date: Sat, 31 Mar 2018 06:10:30 +0200 Message-ID: Subject: Re: [PATCH v7 13/13] pack-objects: reorder members to shrink struct object_entry To: Jeff King Cc: =?UTF-8?B?w4Z2YXIgQXJuZmrDtnLDsCBCamFybWFzb24=?= , Eric Wong , Git Mailing List , Junio C Hamano Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Fri, Mar 30, 2018 at 11:26 PM, Jeff King wrote: > On Sat, Mar 24, 2018 at 07:33:53AM +0100, Nguy=E1=BB=85n Th=C3=A1i Ng=E1= =BB=8Dc Duy wrote: > >> Previous patches leave lots of holes and padding in this struct. This >> patch reorders the members and shrinks the struct down to 80 bytes >> (from 136 bytes, before any field shrinking is done) with 16 bits to >> spare (and a couple more in in_pack_header_size when we really run out >> of bits). > > Out of curiosity, did you count this yourself, or did you double-check > with a few compilers to make sure they all produce the same result? I used pahole though only with .o files created by gcc 64-bit. I'll try the 32-bit version and clang as well. --=20 Duy