Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756087Ab0DURy2 (ORCPT ); Wed, 21 Apr 2010 13:54:28 -0400 Received: from relay3.sgi.com ([192.48.152.1]:40834 "EHLO relay.sgi.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756033Ab0DURy1 (ORCPT ); Wed, 21 Apr 2010 13:54:27 -0400 Message-ID: <4BCF3BCE.7050906@sgi.com> Date: Wed, 21 Apr 2010 10:54:22 -0700 From: Mike Travis User-Agent: Thunderbird 2.0.0.23 (X11/20090817) MIME-Version: 1.0 To: Rik van Riel CC: Hedi Berriche , Alan Cox , Ingo Molnar , Greg Kroah-Hartman , Linus Torvalds , Jack Steiner , Andrew Morton , Robin Holt , LKML Subject: Re: [Patch 1/1] init: Provide a kernel start parameter to increase pid_max v2 References: <4BCE579C.5070100@sgi.com> <4BCE5A73.3000904@sgi.com> <20100421102350.4c222e6b@lxorguk.ukuu.org.uk> <20100421165934.GN16427@zorg.emea.sgi.com> <4BCF336B.1050706@redhat.com> In-Reply-To: <4BCF336B.1050706@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1176 Lines: 33 Rik van Riel wrote: > On 04/21/2010 12:59 PM, Hedi Berriche wrote: >> On Wed, Apr 21, 2010 at 10:20 Alan Cox wrote: >> |> of 32k will not be enough. A system with 1664 CPU's, there are >> 25163 processes >> |> started before the login prompt. It's estimated that with 2048 >> CPU's we will pass >> | >> | Is that perhaps the bug not the 32K limit? >> >> Doubt it: I just checked on an *idle* 1664 CPUs system and I can see >> 26844 >> tasks, all but few being kernel threads. > > That is 15 kernel threads per CPU. > > Reducing the number of kernel threads sounds like a > useful thing to do. I'm doing more research but all the udev modprobes seem to spawn quite a few tasks. And even though they go away, when the pid pool is limited, I'm guessing many of them are waiting. On the last test I did yesterday, the pid # was up in the 77000 range at the login prompt (I started the 1664 cpu system with pid_max=128k). -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/