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+ker...@arm.linux.org.uk>
Suggested-by: Venki Pallipadi <ve...@google.com>
Signed-off-by: Dmitry Antipov <dmitry.anti...@linaro.org>
---
 Documentation/kernel-parameters.txt |    9 +++++----
 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 ++++++++++++
 8 files changed, 40 insertions(+), 18 deletions(-)
 create mode 100644 lib/irqtime.c

diff --git a/Documentation/kernel-parameters.txt 
b/Documentation/kernel-parameters.txt
index 033d4e6..b64a13f 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1719,6 +1719,9 @@ bytes respectively. Such letter suffixes can also be 
entirely omitted.
 
        noautogroup     Disable scheduler automatic task group creation.
 
+       noirqtime       [X86,ARM] Used to run time disable IRQ_TIME_ACCOUNTING,
+                       should give a negligible performance improvement.       
                
+
        nobats          [PPC] Do not use BATs for mapping kernel lowmem
                        on "Classic" PPC cores.
 
@@ -2636,10 +2639,8 @@ bytes respectively. Such letter suffixes can also be 
entirely omitted.
                        as the stability checks done at bootup. Used to enable
                        high-resolution timer mode on older hardware, and in
                        virtualized environment.
-                       [x86] noirqtime: Do not use TSC to do irq accounting.
-                       Used to run time disable IRQ_TIME_ACCOUNTING on any
-                       platforms where RDTSC is slow and this accounting
-                       can add overhead.
+                       [x86] noirqtime: obsoleted by "noirqtime" generic 
option,
+                       see it's documentation for details.
 
        turbografx.map[2|3]=    [HW,JOY]
                        TurboGraFX parallel port interface
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);
-- 
1.7.7.6


_______________________________________________
linaro-dev mailing list
linaro-dev@lists.linaro.org
http://lists.linaro.org/mailman/listinfo/linaro-dev

Reply via email to