From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff King Subject: Re: pack-object's try_delta fast path for v2 trees? Date: Mon, 14 Oct 2013 20:54:17 -0400 Message-ID: <20131015005417.GA16502@sigill.intra.peff.net> References: <20131015001926.GC10415@sigill.intra.peff.net> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Cc: Nicolas Pitre , Git Mailing List To: Duy Nguyen X-From: git-owner@vger.kernel.org Tue Oct 15 02:54:25 2013 Return-path: Envelope-to: gcvg-git-2@plane.gmane.org Received: from vger.kernel.org ([209.132.180.67]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1VVsu0-0007up-8H for gcvg-git-2@plane.gmane.org; Tue, 15 Oct 2013 02:54:24 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755796Ab3JOAyU (ORCPT ); Mon, 14 Oct 2013 20:54:20 -0400 Received: from cloud.peff.net ([50.56.180.127]:49437 "HELO peff.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1750738Ab3JOAyU (ORCPT ); Mon, 14 Oct 2013 20:54:20 -0400 Received: (qmail 28187 invoked by uid 102); 15 Oct 2013 00:54:20 -0000 Received: from c-71-63-4-13.hsd1.va.comcast.net (HELO sigill.intra.peff.net) (71.63.4.13) (smtp-auth username relayok, mechanism cram-md5) by peff.net (qpsmtpd/0.84) with ESMTPA; Mon, 14 Oct 2013 19:54:20 -0500 Received: by sigill.intra.peff.net (sSMTP sendmail emulation); Mon, 14 Oct 2013 20:54:17 -0400 Content-Disposition: inline In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Tue, Oct 15, 2013 at 07:49:57AM +0700, Nguyen Thai Ngoc Duy wrote: > I see this as pack-objects peformance improvements only. If we could > make pack-objects run like 10% faster (even only with -adf), then it > may be worth trying. The 10% is a total guess though as I haven't > checked how much time we spend in searching deltas. For "repack -ad", generally we don't spend that much time on deltas. It depends what your pre-repack state is, of course, but I find that most of the time goes to "counting objects". With "-adf", I would guess that we easily spend something like 95% of the time on compressing for a large repository (just try "repack -adf" on the kernel; even with 8 cores it's a half hour or more on my machine, versus about 25 seconds to count the objects). So I think you could potentially get a lot of speedup for the "-adf" case (and likewise "git gc --aggressive"). -Peff