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-rw-r--r--arch/x86/Kconfig11
-rw-r--r--arch/x86/kernel/tsc.c8
2 files changed, 19 insertions, 0 deletions
diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index fd227d6b8d9c..89b88e3a56e9 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -799,6 +799,17 @@ config SCHED_MC
making when dealing with multi-core CPU chips at a cost of slightly
increased overhead in some places. If unsure say N here.
+config IRQ_TIME_ACCOUNTING
+ bool "Fine granularity task level IRQ time accounting"
+ default n
+ ---help---
+ Select this option to enable fine granularity task irq time
+ accounting. This is done by reading a timestamp on each
+ transitions between softirq and hardirq state, so there can be a
+ small performance impact.
+
+ If in doubt, say N here.
+
source "kernel/Kconfig.preempt"
config X86_UP_APIC
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 26a863a9c2a8..a1c2cd768538 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -104,10 +104,14 @@ int __init notsc_setup(char *str)
__setup("notsc", notsc_setup);
+static int no_sched_irq_time;
+
static int __init tsc_setup(char *str)
{
if (!strcmp(str, "reliable"))
tsc_clocksource_reliable = 1;
+ if (!strncmp(str, "noirqtime", 9))
+ no_sched_irq_time = 1;
return 1;
}
@@ -801,6 +805,7 @@ void mark_tsc_unstable(char *reason)
if (!tsc_unstable) {
tsc_unstable = 1;
sched_clock_stable = 0;
+ disable_sched_clock_irqtime();
printk(KERN_INFO "Marking TSC unstable due to %s\n", reason);
/* Change only the rating, when not registered */
if (clocksource_tsc.mult)
@@ -987,6 +992,9 @@ void __init tsc_init(void)
/* now allow native_sched_clock() to use rdtsc */
tsc_disabled = 0;
+ if (!no_sched_irq_time)
+ enable_sched_clock_irqtime();
+
lpj = ((u64)tsc_khz * 1000);
do_div(lpj, HZ);
lpj_fine = lpj;