From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 9182 invoked by alias); 18 Jan 2011 15:21:40 -0000 Received: (qmail 9173 invoked by uid 22791); 18 Jan 2011 15:21:37 -0000 X-SWARE-Spam-Status: No, hits=-5.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,SPF_HELO_PASS,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 18 Jan 2011 15:21:34 +0000 Received: from int-mx12.intmail.prod.int.phx2.redhat.com (int-mx12.intmail.prod.int.phx2.redhat.com [10.5.11.25]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id p0IFLWSI002449 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK); Tue, 18 Jan 2011 10:21:33 -0500 Received: from fche.csb (vpn-8-67.rdu.redhat.com [10.11.8.67]) by int-mx12.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id p0IFLWhM025782; Tue, 18 Jan 2011 10:21:32 -0500 Received: by fche.csb (Postfix, from userid 2569) id D5FFA58153; Tue, 18 Jan 2011 10:21:31 -0500 (EST) To: "Turgis, Frederic" Cc: "systemtap@sourceware.org" Subject: Re: control channel usermode polling vs runtime "IO check" kernel thread References: <13872098A06B02418CF379A158C0F146015C003539@dnce02.ent.ti.com> From: fche@redhat.com (Frank Ch. Eigler) Date: Tue, 18 Jan 2011 15:21:00 -0000 In-Reply-To: <13872098A06B02418CF379A158C0F146015C003539@dnce02.ent.ti.com> (Frederic Turgis's message of "Tue, 18 Jan 2011 15:42:15 +0100") Message-ID: User-Agent: Gnus/5.1008 (Gnus v5.10.8) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2011-q1/txt/msg00049.txt.bz2 f-turgis wrote: > [...] While using systemtap on a SoC with power management enabled > and "tickless" kernel, I have observed regular wake-ups of > systemtap/0 kernel thread ever> y scheduler tick. I have related > that to below observations/conclusions: I believe all of your observations are correct. We haven't sufficiently tuned this aspect of the system, and would appreciate further advice or help. - FChE