Messages in this thread | | | Subject | dynticks: CONFIG_VIRT_CPU_ACCOUNTING + CONFIG_CONTEXT_TRACKING breaks accounting on core2 CPUs only | From | Mike Galbraith <> | Date | Sun, 12 May 2013 10:17:49 +0200 |
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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
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