Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752157Ab3ELIRz (ORCPT ); Sun, 12 May 2013 04:17:55 -0400 Received: from moutng.kundenserver.de ([212.227.17.9]:51592 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751848Ab3ELIRx (ORCPT ); Sun, 12 May 2013 04:17:53 -0400 Message-ID: <1368346669.5998.13.camel@marge.simpson.net> Subject: dynticks: CONFIG_VIRT_CPU_ACCOUNTING + CONFIG_CONTEXT_TRACKING breaks accounting on core2 CPUs only From: Mike Galbraith To: LKML Cc: Frederic Weisbecker , "Paul E. McKenney" Date: Sun, 12 May 2013 10:17:49 +0200 Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.2.3 Content-Transfer-Encoding: 7bit Mime-Version: 1.0 X-Provags-ID: V02:K0:rhaMxfNFygn4GgiZ2PYLJgyHi73O9eWVR/MQPChJa+O B0v28jvtdRE3X6nhOJKEY8MW6c/fI6FyaGke6S45AUjttT1znt sIX0F2ndkhT8pU8a2BxLzRCcPhAs/XwtsHKlZULVLLkjMlfVf0 qbIpInq/VASy//acKOLWdQph37RH9CVz7+p7cI6uphgVyiGgsp 84gWBEPa76pwRFrILgyan29UD+KgXTK2jQgSmw/okBZhr+UoqX CVkFHjgQQhW0vEzFYdjMFRCFH4rD8mPYvF4/raH/hAHthrox0Q 53PYiE0R0lAbCjr2lVm27+ztZW6w01vGJVxBints6sNPyumyxy pwtzVUkKXc8hn3Db5tvrA7NCMGVZmjKXfS0rUmmNEsVKLF4JNX 41Mc0n0wYPoCQ== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1586 Lines: 46 Greetings, Turning on new NO_HZ feature on my Q6600 box in master, I see that tasks accrue zero utime/stime. However, the same exact kernel on E5620 box works fine, so it would appear there's a CPU dependency somewhere. Is core2 expected to go dysfunctional with context tracking enabled? CONFIG_VIRT_CPU_ACCOUNTING alone works fine in 3.9-stable, turn on CONFIG_CONTEXT_TRACKING_FORCE, and CPU accounting stops working on core2 boxen only, same exact kernel continues to work just fine on E5620 (Westmere) box. -Mike marge:/usr/local/src/kernel/linux-3.9 # egrep 'NO_HR|CPU_ACCOUNTING|RCU| CONTEXT' .config CONFIG_VIRT_CPU_ACCOUNTING=y # CONFIG_TICK_CPU_ACCOUNTING is not set CONFIG_VIRT_CPU_ACCOUNTING_GEN=y # RCU Subsystem CONFIG_TREE_RCU=y # CONFIG_PREEMPT_RCU is not set CONFIG_RCU_STALL_COMMON=y CONFIG_CONTEXT_TRACKING=y # CONFIG_RCU_USER_QS is not set CONFIG_CONTEXT_TRACKING_FORCE=y CONFIG_RCU_FANOUT=64 CONFIG_RCU_FANOUT_LEAF=16 # CONFIG_RCU_FANOUT_EXACT is not set # CONFIG_RCU_FAST_NO_HZ is not set # CONFIG_TREE_RCU_TRACE is not set # CONFIG_RCU_NOCB_CPU is not set CONFIG_HAVE_CONTEXT_TRACKING=y # RCU Debugging # CONFIG_SPARSE_RCU_POINTER is not set # CONFIG_RCU_TORTURE_TEST is not set CONFIG_RCU_CPU_STALL_TIMEOUT=21 # CONFIG_RCU_CPU_STALL_INFO is not set # CONFIG_RCU_TRACE is not set CONFIG_CONTEXT_SWITCH_TRACER=y -- 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/