cputime: Generalize CONFIG_VIRT_CPU_ACCOUNTING

S390, ia64 and powerpc all define their own version
of CONFIG_VIRT_CPU_ACCOUNTING. Generalize the config
and its description to a single place to avoid
duplication.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/init/Kconfig b/init/Kconfig
index af6c7f8ba019..c40d0fb044ef 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -267,6 +267,19 @@ config POSIX_MQUEUE_SYSCTL
         depends on SYSCTL
         default y
 
+config VIRT_CPU_ACCOUNTING
+        bool "Deterministic task and CPU time accounting"
+        depends on HAVE_VIRT_CPU_ACCOUNTING
+        default y if PPC64
+        help
+          Select this option to enable more accurate task and CPU time
+          accounting.  This is done by reading a CPU counter on each
+          kernel entry and exit and on transitions within the kernel
+          between system, softirq and hardirq state, so there is a
+          small performance impact.  In the case of s390 or IBM POWER > 5,
+          this also enables accounting of stolen time on logically-partitioned
+          systems.
+
 config BSD_PROCESS_ACCT
         bool "BSD Process Accounting"
         help