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: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by dcvr.yhbt.net (Postfix) with ESMTP id 53BDF1F87F for ; Mon, 12 Nov 2018 16:21:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729581AbeKMCPt (ORCPT ); Mon, 12 Nov 2018 21:15:49 -0500 Received: from cloud.peff.net ([104.130.231.41]:36042 "HELO cloud.peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1729373AbeKMCPt (ORCPT ); Mon, 12 Nov 2018 21:15:49 -0500 Received: (qmail 484 invoked by uid 109); 12 Nov 2018 16:21:53 -0000 Received: from Unknown (HELO peff.net) (10.0.1.2) by cloud.peff.net (qpsmtpd/0.94) with SMTP; Mon, 12 Nov 2018 16:21:53 +0000 Authentication-Results: cloud.peff.net; auth=none Received: (qmail 12800 invoked by uid 111); 12 Nov 2018 16:21:12 -0000 Received: from sigill.intra.peff.net (HELO sigill.intra.peff.net) (10.0.0.7) by peff.net (qpsmtpd/0.94) with (ECDHE-RSA-AES256-GCM-SHA384 encrypted) SMTP; Mon, 12 Nov 2018 11:21:12 -0500 Authentication-Results: peff.net; auth=none Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Mon, 12 Nov 2018 11:21:51 -0500 Date: Mon, 12 Nov 2018 11:21:51 -0500 From: Jeff King To: =?utf-8?B?w4Z2YXIgQXJuZmrDtnLDsA==?= Bjarmason Cc: Geert Jansen , Junio C Hamano , "git@vger.kernel.org" , =?utf-8?B?UmVuw6k=?= Scharfe , Takuto Ikuta Subject: Re: [PATCH 8/9] sha1-file: use loose object cache for quick existence check Message-ID: <20181112162150.GB7612@sigill.intra.peff.net> References: <20181112144627.GA2478@sigill.intra.peff.net> <20181112145442.GH7400@sigill.intra.peff.net> <87ftw62sld.fsf@evledraar.gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87ftw62sld.fsf@evledraar.gmail.com> Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Mon, Nov 12, 2018 at 05:01:02PM +0100, Ævar Arnfjörð Bjarmason wrote: > > There's some obvious hand-waving in the paragraphs above. I would love > > it if somebody with an NFS system could do some before/after timings > > with various numbers of loose objects, to get a sense of where the > > breakeven point is. > > > > My gut is that we do not need the complexity of a cache-size limit, nor > > of a config option to disable this. But it would be nice to have a real > > number where "reasonable" ends and "pathological" begins. :) > > I'm happy to test this on some of the NFS we have locally, and started > out with a plan to write some for-loop using the low-level API (so it > would look up all 256), fake populate .git/objects/?? with N number of > objects etc, but ran out of time. > > Do you have something ready that you think would be representative and I > could just run? If not I'll try to pick this up again... No, but they don't even really need to be actual objects. So I suspect something like: git init for i in $(seq 256); do i=$(printf %02x $i) mkdir -p .git/objects/$i for j in $(seq --format=%038g 1000); do echo foo >.git/objects/$i/$j done done git index-pack -v --stdin