From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pete Wyckoff Subject: Re: "git grep" parallelism question Date: Sun, 5 May 2013 11:40:01 -0400 Message-ID: <20130505154001.GA25257@padd.com> References: <7vr4hxw2mp.fsf@alter.siamese.dyndns.org> <7vip39w14d.fsf@alter.siamese.dyndns.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Junio C Hamano , Git Mailing List To: Linus Torvalds X-From: git-owner@vger.kernel.org Sun May 05 17:40:14 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 1UZ12r-00088F-Eb for gcvg-git-2@plane.gmane.org; Sun, 05 May 2013 17:40:13 +0200 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751885Ab3EEPkG (ORCPT ); Sun, 5 May 2013 11:40:06 -0400 Received: from honk.padd.com ([74.3.171.149]:52208 "EHLO honk.padd.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751811Ab3EEPkF (ORCPT ); Sun, 5 May 2013 11:40:05 -0400 Received: from arf.padd.com (unknown [50.55.134.154]) by honk.padd.com (Postfix) with ESMTPSA id 6028920C2; Sun, 5 May 2013 08:40:04 -0700 (PDT) Received: by arf.padd.com (Postfix, from userid 7770) id DF77B226B7; Sun, 5 May 2013 11:40:01 -0400 (EDT) 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: torvalds@linux-foundation.org wrote on Fri, 26 Apr 2013 13:31 -0700: > Anyway, I think your patch is good if for no other reason that it > allows this kind of testing, but at least for my machine, clearly the > current default of eight threads is actually "good enough". Maybe > somebody with a very different machine might want to run the above > script and see if how sensitive other machines are to this parameter.. NFS numbers behave as expected: IO concurrency is key. WARM 1 real 0m23.147s 2 real 0m13.913s 4 real 0m6.958s 8 real 0m4.104s 16 real 0m3.588s 32 real 0m3.212s 64 real 0m3.173s COLD 1 real 1m36.969s 2 real 0m51.627s 4 real 0m32.994s 8 real 0m25.657s 16 real 0m21.260s 32 real 0m18.138s 64 real 0m17.265s I am tempted to change the default locally from 8 to 32. -- Pete