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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 6130CC47E4D for ; Wed, 14 Jul 2021 20:08:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4C762613C0 for ; Wed, 14 Jul 2021 20:08:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235751AbhGNULc (ORCPT ); Wed, 14 Jul 2021 16:11:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54180 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S244219AbhGNULD (ORCPT ); Wed, 14 Jul 2021 16:11:03 -0400 Received: from mail-oi1-x22e.google.com (mail-oi1-x22e.google.com [IPv6:2607:f8b0:4864:20::22e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2456C09CE66 for ; Wed, 14 Jul 2021 13:03:54 -0700 (PDT) Received: by mail-oi1-x22e.google.com with SMTP id e11so624802oii.9 for ; Wed, 14 Jul 2021 13:03:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=Z4qzze5X150n1lSjjVtKPittKmZmQiKpQK75YZoLWtE=; b=n8Gxns4lDFI+po1M0O5O/f3R9CXltlTRB4sadYK+jMtChGHyTBuZffJ9NNEVpCqav3 QVAAeaJY1Nwnm/GjcnFft9/q3y8HmJyHsfI14YA5nqwrN+UqwLa9WMtn0moRlqdEezp4 oh4olJU+FvmFsAjqxSBPqXJWSI2i3Zl3fbSKJIabI9iMlu+ciZSsZRRQfyZOq2XnWerq GTTwKcuOiCxaIVQHwWgxBSHd/5WRYjCK7WzsZbXJpHfJjbukthTCfC+mHP0wh6JP3EB+ Pmf4sINylhjkos4Iw4dEqjHgsVvYnoNK6Bqbu3mX9ZccMczcqzNFp8x3AQaVw2AQb8GH U0tA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Z4qzze5X150n1lSjjVtKPittKmZmQiKpQK75YZoLWtE=; b=Tw4/EgjLe8Ef8kiV/L9CZlsKgVHI2S86hW0IBtBqhJf4FFHWqGGBUtYqrIdn+BXWt0 R7ZWCeA0yyXCW7AZdCYzXUcwL+gU/tWlnasOI34YYf51SOJY2YISVAFPZ4yfMaGd64Qe ly1annhXSI4DxeiN0USLicegJGh4mo2Av8qThq9Uy6rGEuFmr588zYcAUvXDiBJCKnLk CjVHEdKiTj3iNk8IWlEPI/yqzgF69jr5P2JAomWYuyhlClxGmltZBa/f4NB9cPGqiozD eecGVI7STrKgI/nWG7EZLitMEH0jCqUQeDqg66eLVnTbNawcyKiXEu1YkXG8lB3oeCZP u2LQ== X-Gm-Message-State: AOAM531PWSAhFC65A+2T7P8WlCcprW4pBOSgDv6Zpnn5ffyQ2Iz/ca1U cxiiKw0DpCfcCdjff0d5AplWvIVNCuBEvWYJM94ir7ZDNLk9MQ== X-Google-Smtp-Source: ABdhPJwSUGdert6muADvzkIHrKqCS2uD3XAvS2BTehYHfbLsJuj5OV7Ezkcd01OF9tKNXSwYnPK0LDST4Rj/1Tfpiz8= X-Received: by 2002:aca:acc5:: with SMTP id v188mr4087914oie.167.1626293034069; Wed, 14 Jul 2021 13:03:54 -0700 (PDT) MIME-Version: 1.0 References: <8f1deb6dd16a0c0d88cf594d2019b3096dbe5383.1626225154.git.gitgitgadget@gmail.com> In-Reply-To: From: Elijah Newren Date: Wed, 14 Jul 2021 13:03:43 -0700 Message-ID: Subject: Re: [PATCH v2 4/4] Bump rename limit defaults (yet again) To: Jeff King Cc: Elijah Newren via GitGitGadget , Git Mailing List , Bagas Sanjaya , Eric Sunshine , Derrick Stolee , =?UTF-8?B?w4Z2YXIgQXJuZmrDtnLDsCBCamFybWFzb24=?= Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org On Wed, Jul 14, 2021 at 10:57 AM Jeff King wrote: > > On Wed, Jul 14, 2021 at 10:32:56AM -0700, Elijah Newren wrote: > > > > It's slightly sad that we only got a 30% CPU improvement in the past 10 > > > years. Are you just counting clock speed as a short-hand here? I think > > > that doesn't tell the whole story. But all of this is a side-note > > > anyway. What I care about is your actual timings. :) > > > > I'm using shorthand when discussing file sizes above (though I used > > actual measurements when picking new values below). But the 30% came > > from measuring the timings with the exact same sample file as you and > > using a lightly modified version of your original script (tweaked to > > also change file basenames) on an AWS c5xlarge instance. My timings > > showed they were only about 30% faster than what you got when you last > > bumped the limits. > > Interesting. My timings are much faster. With a 20k file, I get (on my > laptop, which is an i9-9880H): > > N CPU (2008) CPU (now) > 10 0.43s 0.007s > 100 0.44s 0.071s > 200 1.40s 0.226s > 400 4.87s 0.788s > 800 18.08s 2.887s > 1000 27.82s 4.431s > > The 2008 timings are from the old email you linked in your commit > message, and the new one is from running the revised script you showed. > The savings seem like more than 30%. I don't know if that's all CPU or > if something changed in the code. I was using the script you wrote in 2008, but comparing to your reported numbers in 2011[1]. When you bumped in 2011, you said you picked the limits of 400 & 1000 in order to give rough timings of 2s and 10s. So the table looks more like: N CPU (2008) CPU (2011) c5xlarge CPU (yours) 400 4.87s ~2s 1.106s 0.788s 1000 27.82s ~10s 6.350s 4.431s So, 2011->c5xlarge on these (just recomputed now numbers) show improvements of ~45% and ~36%. Maybe I had an outlier run earlier that was in the upper 6s range for N=1000 and I rounded off to 30% for the commit message? Don't know, those numbers are on a laptop that died in the last few days. But yeah, you are seeing a bigger improvement than I did; 2011->your current laptop shows roughly 56% - 60% improvement. [1] https://lore.kernel.org/git/20110219102128.GB22508@sigill.intra.peff.net/ > Using a 3k file (the median for ls-tree), numbers are similar, but a > little smaller (my n=1300 is about 1.4s). So I think we're both in the > same ballpark (and certainly an AWS machine is a perfectly fine > representative sample of where people might run Git). Yeah, dividing any of the timings I get by the ones you get seem to be giving a value somewhere around 1.4, so that seems reassuring on the consistency front. That doesn't fix my jealousy of your faster CPU, but that's a separate problem. :-)