On Wed, Feb 8, 2012 at 8:08 AM, Dmitry Antipov dmitry.antipov@linaro.org wrote:

Generalize CONFIG_IRQ_TIME_ACCOUNTING  between X86 and ARM, move "noirqtime=" option to common debugging code. For a bit of backward compatibility, X86-specific option "tsc=noirqtime" is preserved, but issues a warning.

Suggested-by: Russell King rmk+kernel@arm.linux.org.uk Suggested-by: Venki Pallipadi venki@google.com Signed-off-by: Dmitry Antipov dmitry.antipov@linaro.org

---

arch/arm/kernel/sched_clock.c |    3 +++  arch/x86/Kconfig              |   11 -----------  arch/x86/kernel/tsc.c         |    7 ++++---  include/linux/sched.h         |    2 ++  lib/Kconfig.debug             |   12 ++++++++++++  lib/Makefile                  |    2 ++  lib/irqtime.c                 |   12 ++++++++++++  7 files changed, 35 insertions(+), 14 deletions(-)  create mode 100644 lib/irqtime.c

diff --git a/arch/arm/kernel/sched_clock.c b/arch/arm/kernel/sched_clock.c index 5416c7c..961bd2d 100644 --- a/arch/arm/kernel/sched_clock.c +++ b/arch/arm/kernel/sched_clock.c @@ -144,6 +144,9 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)         */        cd.epoch_ns = 0;

• if (!no_sched_irq_time)
• enable_sched_clock_irqtime();

pr_debug("Registered %pF as sched_clock source\n", read);  }

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 5bed94e..4759676 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -805,17 +805,6 @@ 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 a62c201..70510a3 100644 --- a/arch/x86/kernel/tsc.c +++ b/arch/x86/kernel/tsc.c @@ -103,14 +103,15 @@ 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))

• if (!strncmp(str, "noirqtime", 9)) {
• printk(KERN_WARNING "tsc: tsc=noirqtime is "
• "obsolete, use noirqtime instead\n");

no_sched_irq_time = 1;

• }

return 1;  }

diff --git a/include/linux/sched.h b/include/linux/sched.h index 7d379a6..b3575b5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1966,9 +1966,11 @@ extern void sched_clock_idle_wakeup_event(u64 delta_ns);  * The reason for this explicit opt-in is not to have perf penalty with  * slow sched_clocks.  */ +extern int no_sched_irq_time;  extern void enable_sched_clock_irqtime(void);  extern void disable_sched_clock_irqtime(void);  #else +#define no_sched_irq_time 1  static inline void enable_sched_clock_irqtime(void) {}  static inline void disable_sched_clock_irqtime(void) {}  #endif diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 8745ac7..236e814 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -299,6 +299,18 @@ config SCHEDSTATS          application, you can say N to avoid the very slight overhead          this adds.

+config IRQ_TIME_ACCOUNTING

• bool "Fine granularity task level IRQ time accounting"
• depends on X86 || ARM
• 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.

config TIMER_STATS        bool "Collect kernel timers statistics"        depends on DEBUG_KERNEL && PROC_FS diff --git a/lib/Makefile b/lib/Makefile index 18515f0..44d67d4 100644 --- a/lib/Makefile +++ b/lib/Makefile @@ -49,6 +49,8 @@ obj-$(CONFIG_DEBUG_PREEMPT) += smp_processor_id.o  obj-$(CONFIG_DEBUG_LIST) += list_debug.o  obj-$(CONFIG_DEBUG_OBJECTS) += debugobjects.o

+obj-$(CONFIG_IRQ_TIME_ACCOUNTING) += irqtime.o

ifneq ($(CONFIG_HAVE_DEC_LOCK),y)   lib-y += dec_and_lock.o  endif diff --git a/lib/irqtime.c b/lib/irqtime.c new file mode 100644 index 0000000..10d440d --- /dev/null +++ b/lib/irqtime.c @@ -0,0 +1,12 @@ +#include <linux/kernel.h> +#include <linux/sched.h>

+int no_sched_irq_time;

+static int __init irqtime_setup(char *str) +{

• no_sched_irq_time = 1;
• return 1;

+}

+__setup("noirqtime", irqtime_setup);

One more nit-pick. We need corresponding change in Documentation/kernel-parameters.txt to deprecate tsc=irqtime and add this new param.

1.7.7.6