From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Subject: Re: [PATCH v2 4/4] nmi_backtrace: generate one-line reports for idle cpus Date: Mon, 21 Mar 2016 22:49:35 +0100 Message-ID: <20160321214935.GF6344@twins.programming.kicks-ass.net> References: <1458147733-29338-1-git-send-email-cmetcalf@mellanox.com> <1458147733-29338-5-git-send-email-cmetcalf@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from bombadil.infradead.org ([198.137.202.9]:56272 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750838AbcCUVtt (ORCPT ); Mon, 21 Mar 2016 17:49:49 -0400 Content-Disposition: inline In-Reply-To: <1458147733-29338-5-git-send-email-cmetcalf@mellanox.com> Sender: linux-arch-owner@vger.kernel.org List-ID: To: Chris Metcalf Cc: Russell King , Thomas Gleixner , Aaron Tomlin , Ingo Molnar , Andrew Morton , Daniel Thompson , x86@kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, "Rafael J. Wysocki" On Wed, Mar 16, 2016 at 01:02:13PM -0400, Chris Metcalf wrote: > When doing an nmi backtrace of many cores, most of which are idle, > the output is a little overwhelming and very uninformative. Suppress > messages for cpus that are idling when they are interrupted and just > emit one line, "NMI backtrace for N skipped: idling at pc 0xNNN". This is still 100+ lines on a modern system, but better than the many many thousands it would otherwise generate. > We do this by grouping all the cpuidle code together into a new > .cpuidle.text section, and then checking the address of the > interrupted PC to see if it lies within that section. > > Signed-off-by: Chris Metcalf Acked-by: Peter Zijlstra (Intel) Tested-by: Peter Zijlstra (Intel) Please Cc Rafael on the next posting.