From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS53758 23.128.96.0/24 X-Spam-Status: No, score=-3.7 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by dcvr.yhbt.net (Postfix) with ESMTP id CBA3F1F8C6 for ; Wed, 8 Sep 2021 16:34:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348657AbhIHQfa (ORCPT ); Wed, 8 Sep 2021 12:35:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60424 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241837AbhIHQfZ (ORCPT ); Wed, 8 Sep 2021 12:35:25 -0400 Received: from mail-lf1-x131.google.com (mail-lf1-x131.google.com [IPv6:2a00:1450:4864:20::131]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 43F7BC061757 for ; Wed, 8 Sep 2021 09:34:15 -0700 (PDT) Received: by mail-lf1-x131.google.com with SMTP id z2so6100525lft.1 for ; Wed, 08 Sep 2021 09:34:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=jCE6zpKcPf9lHDQp7fVUyDcvAsJuo0kC3xYIYgurKr8=; b=YiU852KXAAQ5GX7LK5iI4srTiRTVDN6lcxfFESHLpnf/mrB6CHPMRtEYABZxue3ESe yUBXHbW9erczwwWS4frHd3zQfWqBISs5s2s5kaoa996ioTrzVyyA3R+kycKwOpyXDIHI otIqBulgZDTWszfaDz/k5tfuiefqDmjPMqlP40Pbhsl2Zb3kWPVpuaXy+G6Ts5Vi+llB YBmaYmw7rqpfZ5eaFtc9FowQYpMT5x4cZVlV0oOfAWwd21lRuQitkmZCE+KGLTG0fF2G T6zQyXOCy6QMIMjyBjaqAHdzS2eLZrQs2ps1pD4IR2zy4fIURRxNxpS1wHUWFAiTaB36 7Y7g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=jCE6zpKcPf9lHDQp7fVUyDcvAsJuo0kC3xYIYgurKr8=; b=l1HNqQ/Hvre3iQDmYIVqtbs7KWwPeXAXWn9mnCseXSdg2dIr08JY14QzUHqSFn4ZaN 6BkuRyc4qy1PXMfG82waD8MIgQmHCjTCBHNlAag7oF8GtyqM+16nuvsEfMh9Ubn6dhxX IQ5UWcYqdhZO6E4ku680lBuRDWanN94RWooz/Ze6d9frYFceVIi+Fco3EoDaCqN8Ouhj 8B72cWJxGSLgzDEKIMLRkgjEKuL2ELLTAYZhkH25FXrmRJndTl4iayA8POxEzTAehmDo 1+Ej3TXr1OHMFjBQBfDq6pTPQYrgE+tCfM0g2TAnPAgx/bWu2wXclk+heUbegvQapnBF zySA== X-Gm-Message-State: AOAM530yzQV5HieJeCnLP2QQqTqM6Ippg0uLeR2Ci5pycWbISprDjKdO aHMQLwcH9zgMU7pr7+JRwW8oyE1e/Ec5MveQ1v1Bf2oduBI= X-Google-Smtp-Source: ABdhPJz3qf7PKCex6VoKobk19zHcWC0hoZVmOBnVtNutvr+J6XYmYlkr/WOkVyJKgRHGIVCMODGQJKOX6n4gxJP6WkU= X-Received: by 2002:ac2:46c4:: with SMTP id p4mr3342112lfo.668.1631118853552; Wed, 08 Sep 2021 09:34:13 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: From: Neeraj Singh Date: Wed, 8 Sep 2021 09:34:04 -0700 Message-ID: Subject: Re: [PATCH v2 0/6] Implement a batched fsync option for core.fsyncObjectFiles To: Junio C Hamano Cc: "Neeraj K. Singh via GitGitGadget" , Git List , Johannes Schindelin , Jeff King , Jeff Hostetler , Christoph Hellwig , =?UTF-8?B?w4Z2YXIgQXJuZmrDtnLDsCBCamFybWFzb24=?= , "Neeraj K. Singh" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Tue, Sep 7, 2021 at 11:44 PM Junio C Hamano wrote: > > Neeraj Singh writes: > > > BTW, I updated the github PR to enable batch mode everywhere, and all > > the tests passed, which is good news to me. > > I doubt that fsyncObjectFiles is something we can reliably test in > CI, either with the new batched thing or with the original "when we > close one, make sure the changes hit the disk platter" approach. So > I am not sure what conclusion we should draw from such an experiment, > other than "ok, it compiles cleanly." After all, unless we cause > system crashes, what we thought we have written and close(2) would > be seen by another process that we spawn after that, with or without > sync, no? The main failure mode I was worried about is that some test or other part of Git is relying on a loose object being immediately available after it is added to the ODB. With batch mode, the loose objects aren't actually available until the bulk checkin is unplugged. I agree that it is not easy to test whether the data is actually going to durable storage at the expected time. FWIW, I did take a disk IO trace on Windows to verify that we are issuing disk writes and flushes at the right time. But that's a one-time test that would be hard to make automated.