From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Kastrup Subject: Re: git-svn metadata commands performance issue Date: Thu, 15 Jan 2015 12:53:38 +0100 Message-ID: <87sifcdzul.fsf@fencepost.gnu.org> References: <20150114203012.GA26023@dcvr.yhbt.net> Mime-Version: 1.0 Content-Type: text/plain Cc: Niluge kiwi , git@vger.kernel.org To: Eric Wong X-From: git-owner@vger.kernel.org Thu Jan 15 12:54:13 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 1YBj06-0001Zb-5P for gcvg-git-2@plane.gmane.org; Thu, 15 Jan 2015 12:54:10 +0100 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752920AbbAOLyF (ORCPT ); Thu, 15 Jan 2015 06:54:05 -0500 Received: from fencepost.gnu.org ([208.118.235.10]:42881 "EHLO fencepost.gnu.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752524AbbAOLyD (ORCPT ); Thu, 15 Jan 2015 06:54:03 -0500 Received: from localhost ([127.0.0.1]:41920 helo=lola) by fencepost.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YBizv-00069b-Uj; Thu, 15 Jan 2015 06:54:00 -0500 Received: by lola (Postfix, from userid 1000) id 688F4E048C; Thu, 15 Jan 2015 12:53:38 +0100 (CET) In-Reply-To: <20150114203012.GA26023@dcvr.yhbt.net> (Eric Wong's message of "Wed, 14 Jan 2015 20:30:12 +0000") User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.0.50 (gnu/linux) Sender: git-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Archived-At: Eric Wong writes: > How big is the parent process which forks the git commands? On Linux at > least, fork() performance is negatively impacted by parent process > memory size. Huh. I thought with the advent of demand-paging, at the very least with copy-on-write, this was supposed to be sort of a non-issue. The old original UNIX version, in contrast, consisted of swapping out the current process without removing the in-memory copy. But since the in-memory copy then did the exec call and since usually the exec call was happy about every page of free memory (we _are_ talking about something like 64kB of total available memory here), that tended to work reasonably well. -- David Kastrup