From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Tim Sander" Subject: Re: Minor page faults from pthread_create() aka still problems with 3.0.12-rt30 Date: Mon, 9 Jan 2012 11:35:39 +0100 Message-ID: <201201091135.39733.tim.sander@hbm.com> References: <4F075DA5.1070307@drcomp.erfurt.thur.de> Mime-Version: 1.0 Content-Type: text/Plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: To: "Adrian Knoth" Return-path: Received: from relay.medianet-world.de ([213.157.0.172]:26963 "HELO relay.medianet-world.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1752381Ab2AIKg0 convert rfc822-to-8bit (ORCPT ); Mon, 9 Jan 2012 05:36:26 -0500 Content-Class: urn:content-classes:message In-Reply-To: <4F075DA5.1070307@drcomp.erfurt.thur.de> Sender: linux-rt-users-owner@vger.kernel.org List-ID: Hi > Simply running the example causes roughly 30 minor page faults. When = I > manually allocate stack memory for the stack (after mlockall() and > mallopt have been called) and use pthread_attr_setstack() before call= ing > pthread_create(), minor page faults drop to 2. >=20 > Does anybody happen to know what is causing these remaining two page > faults? My only guess so far is kernel memory to hold some > organizational data for the new thread after clone() has been invoked= , > but this could also be completely wrong. >=20 > Note that I don't need to get page faults down to 0, I'm only looking > for an explanation to understand the issue at hand to confirm that > pthread_create() must not be used from an RT context. While unfortunatly i can't help i've got the impression that something = is=20 still strange with 3.0.12pmx-rt30. (This is on a arm i.mx35 with some=20 platform adaptations and a cyclic clock interrupt.). I haven't build a = newer=20 version of 3.0-rt yet. See my mail where i describe this problem here. https://lkml.org/lkml/2011/12/7/657 I am ocasionally also seeing a ksoftirqd/0 running on as much cpu as it= gets. This is always when i see the message: sched: RT throttling activated Not the best start into the new year :-(. Best regards Tim Please ignore: Hottinger Baldwin Messtechnik GmbH, Im Tiefen See 45, 64293 Darmstadt, = Germany | www.hbm.com=20 Registered as GmbH (German limited liability corporation) in the commer= cial register at the local court of Darmstadt, HRB 1147 =20 Company domiciled in Darmstadt | CEO: Andreas Huellhorst | Chairman of = the board: James Charles Webster Als Gesellschaft mit beschraenkter Haftung eingetragen im Handelsregist= er des Amtsgerichts Darmstadt unter HRB 1147=20 Sitz der Gesellschaft: Darmstadt | Geschaeftsfuehrung: Andreas Huellhor= st | Aufsichtsratsvorsitzender: James Charles Webster The information in this email is confidential. It is intended solely fo= r the addressee. If you are not the intended recipient, please let me k= now and delete this email. Die in dieser E-Mail enthaltene Information ist vertraulich und ledigli= ch f=C3=BCr den Empfaenger bestimmt. Sollten Sie nicht der eigentliche = Empfaenger sein, informieren Sie mich bitte kurz und loeschen diese E-M= ail. -- To unsubscribe from this list: send the line "unsubscribe linux-rt-user= s" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html