From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nguyen Thai Ngoc Duy Subject: Re: [PATCH 0/9] Prefix-compress on-disk index entries Date: Wed, 2 May 2012 08:58:50 +0700 Message-ID: References: <1333493596-14202-1-git-send-email-gitster@pobox.com> <7vpqbn8hgr.fsf@alter.siamese.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Cc: Junio C Hamano , git@vger.kernel.org To: David Barr X-From: git-owner@vger.kernel.org Wed May 02 03:59:27 2012 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 1SPOql-0008Qa-5k for gcvg-git-2@plane.gmane.org; Wed, 02 May 2012 03:59:27 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757607Ab2EBB7W (ORCPT ); Tue, 1 May 2012 21:59:22 -0400 Received: from mail-wi0-f178.google.com ([209.85.212.178]:45479 "EHLO mail-wi0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757445Ab2EBB7V (ORCPT ); Tue, 1 May 2012 21:59:21 -0400 Received: by wibhq7 with SMTP id hq7so116183wib.1 for ; Tue, 01 May 2012 18:59:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc:content-type; bh=XX6zo7iw9er9k09AqdkksGu23p5tid09u2lT2/Ylv1s=; b=O6pLCHRirO0xhEyuckNq59b9/G0KsBJIOIar4UfDfqajKbsBo8yRjroZa6X8TZEDRs fhmKwN21syYDtbKhh6XdNoIPXwo+91cNOux8PvYKS6hpHHlRhw8LVfx2eupfVEd1CxmD Z+J5EXje8JTNTemmVY2Xk8yCs+igC5+QrtVgjAuKNgJMqoeDfXuVejDUeu38+Kt/uG/J zeywqh28GrHdzJMG/xgkBAUVM7zUmUFmgOsdioOaiExgb5i1fzP1FrLI5Tz5+yHbm7on HAM4jUQnpDjsurWx5u68bdtrhFTLdM8A6yQKixs2xiSPLthaNokMmiFrPrzTlD/0VUAd 4sTg== Received: by 10.180.83.38 with SMTP id n6mr11181363wiy.1.1335923960683; Tue, 01 May 2012 18:59:20 -0700 (PDT) Received: by 10.223.14.193 with HTTP; Tue, 1 May 2012 18:58:50 -0700 (PDT) In-Reply-To: Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: On Fri, Apr 6, 2012 at 3:41 PM, David Barr wrote: > On Thu, Apr 5, 2012 at 4:44 AM, Junio C Hamano wrote: >> Nguyen Thai Ngoc Duy writes: >> >>> On Wed, Apr 4, 2012 at 5:53 AM, Junio C Hamano wrote: >>> ... >>> I wonder what causes user time drop from .29s to .13s here. I think >>> the main patch should increase computation, even only slightly, not >>> less. >> >> The main patch reduced the amount of the data needs to be sent to the >> machinery to checksum and write to disk by about 45%, saving both I/O >> and computation. > > I hacked together a quick patch to try predictive coding the other > fields of the index. I got a further 34% improvement in size over > this series. Patches to come. I just used the previous cache entry as > the predictor and reused varint.h together with zigzag encoding[1]. > > That's a total improvement in size over v2 of 62%. Have you posted (and I missed) the patches? I'm interested in seeing what changes you made. > [1] https://developers.google.com/protocol-buffers/docs/encoding#types -- Duy