From b64f34cdfe5bef9dfed1304c513220b0f2862eca Mon Sep 17 00:00:00 2001 From: Hidetoshi Seto Date: Tue, 29 Jan 2008 14:27:30 +0900 Subject: [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 Signed-off-by: Tony Luck --- arch/ia64/Kconfig | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/ia64/Kconfig') 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 -- cgit v1.2.3