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authorHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>2008-01-29 14:27:30 +0900
committerTony Luck <tony.luck@intel.com>2008-02-20 12:55:37 -0800
commitb64f34cdfe5bef9dfed1304c513220b0f2862eca (patch)
tree04cb9216a9de18afcb27f9bac3fda1f3c7bacbbd /arch/ia64/Kconfig
parent5d9c4a7de64d398604a978d267a6987f1f4025b7 (diff)
[IA64] VIRT_CPU_ACCOUNTING (accurate cpu time accounting)
This patch implements VIRT_CPU_ACCOUNTING for ia64, which enable us to use more accurate cpu time accounting. The VIRT_CPU_ACCOUNTING is an item of kernel config, which s390 and powerpc arch have. By turning this config on, these archs change the mechanism of cpu time accounting from tick-sampling based one to state-transition based one. The state-transition based accounting is done by checking time (cycle counter in processor) at every state-transition point, such as entrance/exit of kernel, interrupt, softirq etc. The difference between point to point is the actual time consumed during in the state. There is no doubt about that this value is more accurate than that of tick-sampling based accounting. Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
Diffstat (limited to 'arch/ia64/Kconfig')
-rw-r--r--arch/ia64/Kconfig11
1 files changed, 11 insertions, 0 deletions
diff --git a/arch/ia64/Kconfig b/arch/ia64/Kconfig
index dff9edfc746..c3567727c13 100644
--- a/arch/ia64/Kconfig
+++ b/arch/ia64/Kconfig
@@ -280,6 +280,17 @@ config FORCE_MAX_ZONEORDER
default "17" if HUGETLB_PAGE
default "11"
+config VIRT_CPU_ACCOUNTING
+ bool "Deterministic task and CPU time accounting"
+ default n
+ 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.
+ If in doubt, say N here.
+
config SMP
bool "Symmetric multi-processing support"
help