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 Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 51C33CA0EC4 for ; Thu, 29 Aug 2024 21:44:25 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id BB67141A64; Thu, 29 Aug 2024 21:44:24 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id H71VyX7Dk47a; Thu, 29 Aug 2024 21:44:23 +0000 (UTC) X-Comment: SPF check N/A for local connections - client-ip=140.211.166.34; helo=ash.osuosl.org; envelope-from=buildroot-bounces@buildroot.org; receiver= DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 8212241A6B Received: from ash.osuosl.org (ash.osuosl.org [140.211.166.34]) by smtp4.osuosl.org (Postfix) with ESMTP id 8212241A6B; Thu, 29 Aug 2024 21:44:23 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) by ash.osuosl.org (Postfix) with ESMTP id B352C1BF5E9 for ; Thu, 29 Aug 2024 21:44:22 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id AD26541A6B for ; Thu, 29 Aug 2024 21:44:22 +0000 (UTC) X-Virus-Scanned: amavis at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavis, port 10024) with ESMTP id TQHBjfvzjNMs for ; Thu, 29 Aug 2024 21:44:21 +0000 (UTC) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=2001:4b98:dc4:8::227; helo=relay7-d.mail.gandi.net; envelope-from=thomas.petazzoni@bootlin.com; receiver= DMARC-Filter: OpenDMARC Filter v1.4.2 smtp4.osuosl.org 56C1241A64 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 56C1241A64 Received: from relay7-d.mail.gandi.net (relay7-d.mail.gandi.net [IPv6:2001:4b98:dc4:8::227]) by smtp4.osuosl.org (Postfix) with ESMTPS id 56C1241A64 for ; Thu, 29 Aug 2024 21:44:21 +0000 (UTC) Received: by mail.gandi.net (Postfix) with ESMTPSA id 1624320002; Thu, 29 Aug 2024 21:44:17 +0000 (UTC) Date: Thu, 29 Aug 2024 23:44:16 +0200 To: Peter Korsgaard Message-ID: <20240829234416.4131264b@windsurf> In-Reply-To: <87ttf47nr6.fsf@dell.be.48ers.dk> References: <20240421095353.208034-1-dario.binacchi@amarulasolutions.com> <20240421095353.208034-2-dario.binacchi@amarulasolutions.com> <20240715160555.6e88961e@windsurf> <87r0a994or.fsf@dell.be.48ers.dk> <20240828154253.206391b0@windsurf> <87ttf47nr6.fsf@dell.be.48ers.dk> Organization: Bootlin X-Mailer: Claws Mail 4.3.0 (GTK 3.24.43; x86_64-redhat-linux-gnu) MIME-Version: 1.0 X-GND-Sasl: thomas.petazzoni@bootlin.com X-Mailman-Original-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1724967858; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=Qg7+WtqrmlgemXO0GD35KylXjcRbh0PZQsUmhB2gftg=; b=PVglgiNB9YZzXFFaYiXpYTok/JLBmNalkbYaFjjczRkCGv8ulWOD+nDGyUuS+F4wdw10jq bUcv4x17Vpmis6ccORiWrt5/YXiWKM+HojQXdeGjZHhfLDao3tBuy1+G7zOjDMpI0wHQnE /Qj+kf4gNYAd+zaQhwdP5QCtGRI5bVdFJL47YEnDf8K/5qZbFMnQb/HRF6if8rz4adteFW xKdPWj/Xc/nlU8exv04D65Q9NsntumHRky+g2vleua2731tbRcP6/kLw835vsFZHgdlobX TKA1jhW3FvkPXGLu7x11nVLBPiPvK2ESK/aOhJMxYmXC/TZkxvHxMEamp3WLmg== X-Mailman-Original-Authentication-Results: smtp4.osuosl.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com X-Mailman-Original-Authentication-Results: smtp4.osuosl.org; dkim=pass (2048-bit key, unprotected) header.d=bootlin.com header.i=@bootlin.com header.a=rsa-sha256 header.s=gm1 header.b=PVglgiNB Subject: Re: [Buildroot] [RFC PATCH 1/2] support/scripts/genimage.sh: support creating a bmap image X-BeenThere: buildroot@buildroot.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion and development of buildroot List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Thomas Petazzoni via buildroot Reply-To: Thomas Petazzoni Cc: michael@amarulasolutions.com, Xuanhao Shi , Thomas Petazzoni via buildroot , Dario Binacchi , linux-amarula@amarulasolutions.com, Anand Gadiyar Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: buildroot-bounces@buildroot.org Sender: "buildroot" Hello Peter, On Wed, 28 Aug 2024 15:58:21 +0200 Peter Korsgaard wrote: > > I understand your concern, but compression is also what helps in making > > those sparse images small. > > NIT: No, it is the sparseness (E.G. the holes). Compression in fact > breaks the holes (replaces them by zeros): You didn't understand my point, and Arnout explained it better on the chat. My point is that it is *very* easy to lose the sparseness. You copy the file around, you share it in Google Drive, or download it over HTTP or what not, and bang the sparseness is lost. Instead, with a compressed file, you get a file that has pretty much the same size as the sparse file, but you can move it around, transfer it, it won't consume its real size. And the bmap metadata file allows to use/flash that compressed file with the same efficiency as the original sparse file. In fact, bmap is quite useless is the file sparseness is retained: instead of using bmap metadata, you could just ask what are the holes of the file and skip them when flashing. So really the whole point of bmap metadata IMO is that they allow to do fast flashing (skipping holes) even if the sparseness of the file has been lost. Thomas -- Thomas Petazzoni, co-owner and CEO, Bootlin Embedded Linux and Kernel engineering and training https://bootlin.com _______________________________________________ buildroot mailing list buildroot@buildroot.org https://lists.buildroot.org/mailman/listinfo/buildroot