From: Mike Galbraith <bitbucket@online.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: dynticks: CONFIG_VIRT_CPU_ACCOUNTING + CONFIG_CONTEXT_TRACKING breaks accounting on core2 CPUs only
Date: Sun, 12 May 2013 10:17:49 +0200 [thread overview]
Message-ID: <1368346669.5998.13.camel@marge.simpson.net> (raw)
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
next reply other threads:[~2013-05-12 8:17 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-12 8:17 Mike Galbraith [this message]
2013-05-14 0:57 ` Frederic Weisbecker
2013-05-14 7:37 ` Mike Galbraith
2013-05-14 14:07 ` Mike Galbraith
2013-05-15 0:26 ` Frederic Weisbecker
2013-05-15 4:09 ` Mike Galbraith
2013-05-15 16:05 ` Frederic Weisbecker
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