From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jonathan Nieder Subject: Re: [PATCH 7/9] fetch: fetch submodules in parallel Date: Fri, 28 Aug 2015 11:20:08 -0700 Message-ID: <20150828182008.GC8165@google.com> References: <1440724495-708-1-git-send-email-sbeller@google.com> <1440724495-708-8-git-send-email-sbeller@google.com> <20150828170141.GB8165@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Stefan Beller , "git@vger.kernel.org" , Jeff King , Johannes Schindelin To: Junio C Hamano X-From: git-owner@vger.kernel.org Fri Aug 28 20:20:21 2015 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 1ZVOGC-0000AW-CR for gcvg-git-2@plane.gmane.org; Fri, 28 Aug 2015 20:20:20 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753243AbbH1SUN (ORCPT ); Fri, 28 Aug 2015 14:20:13 -0400 Received: from mail-pa0-f52.google.com ([209.85.220.52]:35398 "EHLO mail-pa0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753022AbbH1SUM (ORCPT ); Fri, 28 Aug 2015 14:20:12 -0400 Received: by pacdd16 with SMTP id dd16so70110344pac.2 for ; Fri, 28 Aug 2015 11:20:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:cc:subject:message-id:references:mime-version :content-type:content-disposition:in-reply-to:user-agent; bh=tM/tF/TfdT55EolGuIBxZ1MKtmIoZ81U2/kGqK5esgY=; b=diV6ZmjGVkofEFw0b/ShKP56d+30sRJCzmpc7+xoi03Y2jCg19JFYO0sYhucnpQDVB FoTCcpoEK9SkhTzSyApqYKSBjZHuMxFor0i+Qvj0I0phU/t1ZHI2hqWNDkUvte8t8MgJ pYtymAk8XAmmgzKdrxVr+pxYj7uesU26+BE5culJ7B3VQ6P761SK0g+uvN/Jt94dxmNK /PaYwj5HxoLqTI4uBwN65DvOlVmxQTUAHlkYB4Wu72nPff2oCXdQTJGtZPrVJtev4row wMi/SHsTiYYNkhcU9FUEIAPVHpQAXRMRzS7eO0JQ6+cV3sHubXo6B+zTBoJ4X3ziDxit hirQ== X-Received: by 10.66.226.12 with SMTP id ro12mr17504911pac.74.1440786011626; Fri, 28 Aug 2015 11:20:11 -0700 (PDT) Received: from google.com ([2620:0:1000:5b00:d830:475:d6b6:5fa8]) by smtp.gmail.com with ESMTPSA id df2sm6475402pad.19.2015.08.28.11.20.10 (version=TLSv1/SSLv3 cipher=OTHER); Fri, 28 Aug 2015 11:20:10 -0700 (PDT) Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Junio C Hamano wrote: > My preference is still (1) leave standard error output all connected > to the same fd without multiplexing, and (2) line buffer standard > output so that the output is at least readable as a text, in a > similar way a log of an irc channel where everybody is talking at > the same time. There is something nice about the immediacy of seeing output from all the subprocesses at the same time in that model. But for commands that show progress like "git clone", "git checkout", and "git fetch", it does not work well at all. They provide output that updates itself by putting a carriage return at the end of each chunk of output, like this: remote: Finding sources: 11% (18/155) \r remote: Finding sources: 12% (19/155) \r With multiple commands producing such output, they will overwrite each other's lines, producing a mixture that is confusing and unuseful. Even with --no-progress, there is a similar sense of confusion in the intermixed output. Error messages are hard to find. This is a comment complaint about the current "repo sync -j" implementation. Ideally what I as a user want to see is something like what "prove" writes, showing progress on the multiple tasks that are taking place at once: ===( 103;1 0/? 8/? 3/? 11/? 6/? 16/? 1/? 1/? )============== That would require more sophisticated inter-process communication than seems necessary for the first version of parallel "git submodule update". For the first version that people use in the wild, showing output from one of the tasks at a time, simulating a sped-up sequential implementation, seems useful to me. In the degenerate case where only one task is running, it reduces to the current output. The output is familiar and easy to use. I quite like the approach. My two cents, Jonathan