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authorRussell King <rmk+kernel@arm.linux.org.uk>2012-09-09 18:39:28 +0100
committerRussell King <rmk+kernel@arm.linux.org.uk>2012-09-15 21:43:31 +0100
commita42c362980430be74b77ec8f374964f61062379f (patch)
treef49ca2d6f045d49e4cd659a9f8cedb5824481676 /arch/arm
parenta67e1ce145785d884b29b17e4d82a6ecd67bb97a (diff)
downloadop-kernel-dev-a42c362980430be74b77ec8f374964f61062379f.zip
op-kernel-dev-a42c362980430be74b77ec8f374964f61062379f.tar.gz
ARM: Add irqtime accounting support
Add support for irq time accounting. This commit prepares ARM by adding the call to enable_sched_clock_irqtime() in sched_clock(). We introduce a new kernel parameter - irqtime - which takes an integer. -1 for auto, 0 for disabled, and 1 for enabled. Auto mode selects IRQ accounting if we have a sched_clock() tick rate greater than 1MHz. Frederic Weisbecker is working on a patch set which moves the IRQ_TIME_ACCOUNTING into arch/, so that part is not incorporated into this patch; this facility becomes available on ARM only when both this patch and Frederic's patches are merged. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm')
-rw-r--r--arch/arm/kernel/sched_clock.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c
index 27d186a..9b8451a 100644
--- a/arch/arm/kernel/sched_clock.c
+++ b/arch/arm/kernel/sched_clock.c
@@ -9,6 +9,7 @@
#include <linux/init.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
+#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/syscore_ops.h>
#include <linux/timer.h>
@@ -25,6 +26,9 @@ struct clock_data {
static void sched_clock_poll(unsigned long wrap_ticks);
static DEFINE_TIMER(sched_clock_timer, sched_clock_poll, 0, 0);
+static int irqtime = -1;
+
+core_param(irqtime, irqtime, int, 0400);
static struct clock_data cd = {
.mult = NSEC_PER_SEC / HZ,
@@ -145,6 +149,10 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
*/
cd.epoch_ns = 0;
+ /* Enable IRQ time accounting if we have a fast enough sched_clock */
+ if (irqtime > 0 || (irqtime == -1 && rate >= 1000000))
+ enable_sched_clock_irqtime();
+
pr_debug("Registered %pF as sched_clock source\n", read);
}
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