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: Yong Zhang <[email protected]>
Suggested-by: Russell King <[email protected]>
Suggested-by: Venki Pallipadi <[email protected]>
Signed-off-by: Dmitry Antipov <[email protected]>
---
Documentation/kernel-parameters.txt | 9 +++++----
arch/arm/kernel/sched_clock.c | 2 ++
arch/x86/Kconfig | 11 -----------
arch/x86/kernel/tsc.c | 12 ++++++------
include/linux/sched.h | 17 ++++++++++-------
kernel/sched/core.c | 20 +++++++++++---------
lib/Kconfig.debug | 12 ++++++++++++
7 files changed, 46 insertions(+), 37 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 033d4e6..666d20e 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1790,6 +1790,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
noirqdebug [X86-32] Disables the code which attempts to detect and
disable unhandled interrupt sources.
+ noirqtime [X86,ARM] Used to run time disable IRQ_TIME_ACCOUNTING,
+ should give a negligible performance improvement.
+
no_timer_check [X86,APIC] Disables the code which tests for
broken timer IRQ sources.
@@ -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..30b5f89 100644
--- a/arch/arm/kernel/sched_clock.c
+++ b/arch/arm/kernel/sched_clock.c
@@ -144,6 +144,8 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
*/
cd.epoch_ns = 0;
+ 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..f1b2b63 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))
- no_sched_irq_time = 1;
+ if (!strncmp(str, "noirqtime", 9)) {
+ printk(KERN_WARNING "tsc: tsc=noirqtime is "
+ "obsolete, use noirqtime instead\n");
+ disable_sched_clock_irqtime();
+ }
return 1;
}
@@ -978,8 +979,7 @@ 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();
+ enable_sched_clock_irqtime();
lpj = ((u64)tsc_khz * 1000);
do_div(lpj, HZ);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index 7d379a6..9b13f79 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1961,13 +1961,16 @@ extern void sched_clock_idle_wakeup_event(u64 delta_ns);
#endif
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
-/*
- * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
- * The reason for this explicit opt-in is not to have perf penalty with
- * slow sched_clocks.
- */
-extern void enable_sched_clock_irqtime(void);
-extern void disable_sched_clock_irqtime(void);
+extern int sched_clock_irqtime;
+static inline void enable_sched_clock_irqtime(void)
+{
+ if (sched_clock_irqtime == -1)
+ sched_clock_irqtime = 1;
+}
+static inline void disable_sched_clock_irqtime(void)
+{
+ sched_clock_irqtime = 0;
+}
#else
static inline void enable_sched_clock_irqtime(void) {}
static inline void disable_sched_clock_irqtime(void) {}
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 5255c9d..a7ec043 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -757,18 +757,20 @@ static DEFINE_PER_CPU(u64, cpu_hardirq_time);
static DEFINE_PER_CPU(u64, cpu_softirq_time);
static DEFINE_PER_CPU(u64, irq_start_time);
-static int sched_clock_irqtime;
-void enable_sched_clock_irqtime(void)
-{
- sched_clock_irqtime = 1;
-}
+/* -1 if not initialized, 0 if disabled with "noirqtime" kernel option
+ * or after unstable clock was detected, 1 if enabled and active.
+ */
+int sched_clock_irqtime = -1;
-void disable_sched_clock_irqtime(void)
+static int __init irqtime_setup(char *str)
{
sched_clock_irqtime = 0;
+ return 1;
}
+__setup("noirqtime", irqtime_setup);
+
#ifndef CONFIG_64BIT
static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
@@ -822,7 +824,7 @@ void account_system_vtime(struct task_struct *curr)
s64 delta;
int cpu;
- if (!sched_clock_irqtime)
+ if (sched_clock_irqtime < 1)
return;
local_irq_save(flags);
@@ -2853,7 +2855,7 @@ void account_process_tick(struct task_struct *p, int user_tick)
cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
struct rq *rq = this_rq();
- if (sched_clock_irqtime) {
+ if (sched_clock_irqtime > 0) {
irqtime_account_process_tick(p, user_tick, rq);
return;
}
@@ -2887,7 +2889,7 @@ void account_steal_ticks(unsigned long ticks)
void account_idle_ticks(unsigned long ticks)
{
- if (sched_clock_irqtime) {
+ if (sched_clock_irqtime > 0) {
irqtime_account_idle_ticks(ticks);
return;
}
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
--
1.7.7.6
> + ? ? ? noirqtime ? ? ? [X86,ARM] Used to run time disable IRQ_TIME_ACCOUNTING,
> + ? ? ? ? ? ? ? ? ? ? ? should give a negligible performance improvement.
Can you reword the above "negligible performance improvement" above to
something
> + ? ? ? noirqtime ? ? ? [X86,ARM] Run time disables IRQ_TIME_ACCOUNTING and
> + ? ? ? ? ? ? ? ? ? ? ? eliminates the timestamping on irq/softirq entry/exit.
Otherwise,
Acked-by: Venkatesh Pallipadi <[email protected]>
On Thu, Feb 9, 2012 at 9:25 AM, Dmitry Antipov
<[email protected]> 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: Yong Zhang <[email protected]>
> Suggested-by: Russell King <[email protected]>
> Suggested-by: Venki Pallipadi <[email protected]>
> Signed-off-by: Dmitry Antipov <[email protected]>
> ---
> ?Documentation/kernel-parameters.txt | ? ?9 +++++----
> ?arch/arm/kernel/sched_clock.c ? ? ? | ? ?2 ++
> ?arch/x86/Kconfig ? ? ? ? ? ? ? ? ? ?| ? 11 -----------
> ?arch/x86/kernel/tsc.c ? ? ? ? ? ? ? | ? 12 ++++++------
> ?include/linux/sched.h ? ? ? ? ? ? ? | ? 17 ++++++++++-------
> ?kernel/sched/core.c ? ? ? ? ? ? ? ? | ? 20 +++++++++++---------
> ?lib/Kconfig.debug ? ? ? ? ? ? ? ? ? | ? 12 ++++++++++++
> ?7 files changed, 46 insertions(+), 37 deletions(-)
>
> diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
> index 033d4e6..666d20e 100644
> --- a/Documentation/kernel-parameters.txt
> +++ b/Documentation/kernel-parameters.txt
> @@ -1790,6 +1790,9 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
> ? ? ? ?noirqdebug ? ? ?[X86-32] Disables the code which attempts to detect and
> ? ? ? ? ? ? ? ? ? ? ? ?disable unhandled interrupt sources.
>
> + ? ? ? noirqtime ? ? ? [X86,ARM] Used to run time disable IRQ_TIME_ACCOUNTING,
> + ? ? ? ? ? ? ? ? ? ? ? should give a negligible performance improvement.
> +
> ? ? ? ?no_timer_check ?[X86,APIC] Disables the code which tests for
> ? ? ? ? ? ? ? ? ? ? ? ?broken timer IRQ sources.
>
> @@ -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..30b5f89 100644
> --- a/arch/arm/kernel/sched_clock.c
> +++ b/arch/arm/kernel/sched_clock.c
> @@ -144,6 +144,8 @@ void __init setup_sched_clock(u32 (*read)(void), int bits, unsigned long rate)
> ? ? ? ? */
> ? ? ? ?cd.epoch_ns = 0;
>
> + ? ? ? 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..f1b2b63 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))
> - ? ? ? ? ? ? ? no_sched_irq_time = 1;
> + ? ? ? if (!strncmp(str, "noirqtime", 9)) {
> + ? ? ? ? ? ? ? printk(KERN_WARNING "tsc: tsc=noirqtime is "
> + ? ? ? ? ? ? ? ? ? ? ?"obsolete, use noirqtime instead\n");
> + ? ? ? ? ? ? ? disable_sched_clock_irqtime();
> + ? ? ? }
> ? ? ? ?return 1;
> ?}
>
> @@ -978,8 +979,7 @@ 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();
> + ? ? ? enable_sched_clock_irqtime();
>
> ? ? ? ?lpj = ((u64)tsc_khz * 1000);
> ? ? ? ?do_div(lpj, HZ);
> diff --git a/include/linux/sched.h b/include/linux/sched.h
> index 7d379a6..9b13f79 100644
> --- a/include/linux/sched.h
> +++ b/include/linux/sched.h
> @@ -1961,13 +1961,16 @@ extern void sched_clock_idle_wakeup_event(u64 delta_ns);
> ?#endif
>
> ?#ifdef CONFIG_IRQ_TIME_ACCOUNTING
> -/*
> - * An i/f to runtime opt-in for irq time accounting based off of sched_clock.
> - * The reason for this explicit opt-in is not to have perf penalty with
> - * slow sched_clocks.
> - */
> -extern void enable_sched_clock_irqtime(void);
> -extern void disable_sched_clock_irqtime(void);
> +extern int sched_clock_irqtime;
> +static inline void enable_sched_clock_irqtime(void)
> +{
> + ? ? ? if (sched_clock_irqtime == -1)
> + ? ? ? ? ? ? ? sched_clock_irqtime = 1;
> +}
> +static inline void disable_sched_clock_irqtime(void)
> +{
> + ? ? ? sched_clock_irqtime = 0;
> +}
> ?#else
> ?static inline void enable_sched_clock_irqtime(void) {}
> ?static inline void disable_sched_clock_irqtime(void) {}
> diff --git a/kernel/sched/core.c b/kernel/sched/core.c
> index 5255c9d..a7ec043 100644
> --- a/kernel/sched/core.c
> +++ b/kernel/sched/core.c
> @@ -757,18 +757,20 @@ static DEFINE_PER_CPU(u64, cpu_hardirq_time);
> ?static DEFINE_PER_CPU(u64, cpu_softirq_time);
>
> ?static DEFINE_PER_CPU(u64, irq_start_time);
> -static int sched_clock_irqtime;
>
> -void enable_sched_clock_irqtime(void)
> -{
> - ? ? ? sched_clock_irqtime = 1;
> -}
> +/* -1 if not initialized, 0 if disabled with "noirqtime" kernel option
> + * or after unstable clock was detected, 1 if enabled and active.
> + */
> +int sched_clock_irqtime = -1;
>
> -void disable_sched_clock_irqtime(void)
> +static int __init irqtime_setup(char *str)
> ?{
> ? ? ? ?sched_clock_irqtime = 0;
> + ? ? ? return 1;
> ?}
>
> +__setup("noirqtime", irqtime_setup);
> +
> ?#ifndef CONFIG_64BIT
> ?static DEFINE_PER_CPU(seqcount_t, irq_time_seq);
>
> @@ -822,7 +824,7 @@ void account_system_vtime(struct task_struct *curr)
> ? ? ? ?s64 delta;
> ? ? ? ?int cpu;
>
> - ? ? ? if (!sched_clock_irqtime)
> + ? ? ? if (sched_clock_irqtime < 1)
> ? ? ? ? ? ? ? ?return;
>
> ? ? ? ?local_irq_save(flags);
> @@ -2853,7 +2855,7 @@ void account_process_tick(struct task_struct *p, int user_tick)
> ? ? ? ?cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
> ? ? ? ?struct rq *rq = this_rq();
>
> - ? ? ? if (sched_clock_irqtime) {
> + ? ? ? if (sched_clock_irqtime > 0) {
> ? ? ? ? ? ? ? ?irqtime_account_process_tick(p, user_tick, rq);
> ? ? ? ? ? ? ? ?return;
> ? ? ? ?}
> @@ -2887,7 +2889,7 @@ void account_steal_ticks(unsigned long ticks)
> ?void account_idle_ticks(unsigned long ticks)
> ?{
>
> - ? ? ? if (sched_clock_irqtime) {
> + ? ? ? if (sched_clock_irqtime > 0) {
> ? ? ? ? ? ? ? ?irqtime_account_idle_ticks(ticks);
> ? ? ? ? ? ? ? ?return;
> ? ? ? ?}
> 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
> --
> 1.7.7.6
>