* Re: [PATCH] sched: Sanitize irq accounting madness
2014-05-02 21:26 [PATCH] sched: Sanitize irq accounting madness Thomas Gleixner
@ 2014-05-02 21:38 ` Paul E. McKenney
2014-05-08 10:41 ` [tip:sched/core] " tip-bot for Thomas Gleixner
2014-07-09 16:24 ` [PATCH] " Frederic Weisbecker
2 siblings, 0 replies; 4+ messages in thread
From: Paul E. McKenney @ 2014-05-02 21:38 UTC (permalink / raw)
To: Thomas Gleixner
Cc: LKML, Russell King, Ingo Molnar, H. Peter Anvin, Peter Zijlstra,
Frederic Weisbecker, Venkatesh Pallipadi
On Fri, May 02, 2014 at 11:26:24PM +0200, Thomas Gleixner wrote:
> Russell reported, that irqtime_account_idle_ticks() takes ages due to:
>
> for (i = 0; i < ticks; i++)
> irqtime_account_process_tick(current, 0, rq);
>
> It's sad, that this code was written way _AFTER_ the NOHZ idle
> functionality was available. I charge myself guitly for not paying
> attention when that crap got merged with commit abb74cefa (sched:
> Export ns irqtimes through /proc/stat)
>
> So instead of looping nr_ticks times just apply the whole thing at
> once.
>
> As a side note: The whole cputime_t vs. u64 business in that context
> wants to be cleaned up as well. There is no point in having all these
> back and forth conversions. Lets standardise on u64 nsec for all
> kernel internal accounting and be done with it. Everything else does
> not make sense at all for fine grained accounting. Frederic, can you
> please take care of that?
>
> Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: stable@vger.kernel.org
One nit below, other than that:
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
> ---
> kernel/sched/cputime.c | 32 ++++++++++++++++----------------
> 1 file changed, 16 insertions(+), 16 deletions(-)
>
> Index: linux-2.6/kernel/sched/cputime.c
> ===================================================================
> --- linux-2.6.orig/kernel/sched/cputime.c
> +++ linux-2.6/kernel/sched/cputime.c
> @@ -332,50 +332,50 @@ out:
> * softirq as those do not count in task exec_runtime any more.
> */
> static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
> - struct rq *rq)
> + struct rq *rq, int ticks)
> {
> - cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
> + cputime_t scaled = cputime_to_scaled(cputime_one_jiffy);
> + u64 cputime = (__force u64) cputime_one_jiffy;
> u64 *cpustat = kcpustat_this_cpu->cpustat;
>
> if (steal_account_process_tick())
> return;
>
> + cputime *= ticks;
> + scaled *= ticks;
> +
> if (irqtime_account_hi_update()) {
> - cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
> + cpustat[CPUTIME_IRQ] += cputime;
> } else if (irqtime_account_si_update()) {
> - cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
> + cpustat[CPUTIME_SOFTIRQ] += cputime;
> } else if (this_cpu_ksoftirqd() == p) {
> /*
> * ksoftirqd time do not get accounted in cpu_softirq_time.
> * So, we have to handle it separately here.
> * Also, p->stime needs to be updated for ksoftirqd.
> */
> - __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
> - CPUTIME_SOFTIRQ);
> + __account_system_time(p, cputime, scaled, CPUTIME_SOFTIRQ);
> } else if (user_tick) {
> - account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
> + account_user_time(p, cputime, scaled);
> } else if (p == rq->idle) {
> - account_idle_time(cputime_one_jiffy);
> + account_idle_time(cputime);
> } else if (p->flags & PF_VCPU) { /* System time or guest time */
> - account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
> + account_guest_time(p, cputime, scaled);
> } else {
> - __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
> - CPUTIME_SYSTEM);
> + __account_system_time(p, cputime, scaled, CPUTIME_SYSTEM);
Stray tab character.
> }
> }
>
> static void irqtime_account_idle_ticks(int ticks)
> {
> - int i;
> struct rq *rq = this_rq();
>
> - for (i = 0; i < ticks; i++)
> - irqtime_account_process_tick(current, 0, rq);
> + irqtime_account_process_tick(current, 0, rq, ticks);
> }
> #else /* CONFIG_IRQ_TIME_ACCOUNTING */
> static inline void irqtime_account_idle_ticks(int ticks) {}
> static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
> - struct rq *rq) {}
> + struct rq *rq, int nr_ticks) {}
> #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
>
> /*
> @@ -464,7 +464,7 @@ void account_process_tick(struct task_st
> return;
>
> if (sched_clock_irqtime) {
> - irqtime_account_process_tick(p, user_tick, rq);
> + irqtime_account_process_tick(p, user_tick, rq, 1);
> return;
> }
>
>
^ permalink raw reply [flat|nested] 4+ messages in thread* [tip:sched/core] sched: Sanitize irq accounting madness
2014-05-02 21:26 [PATCH] sched: Sanitize irq accounting madness Thomas Gleixner
2014-05-02 21:38 ` Paul E. McKenney
@ 2014-05-08 10:41 ` tip-bot for Thomas Gleixner
2014-07-09 16:24 ` [PATCH] " Frederic Weisbecker
2 siblings, 0 replies; 4+ messages in thread
From: tip-bot for Thomas Gleixner @ 2014-05-08 10:41 UTC (permalink / raw)
To: linux-tip-commits
Cc: linux-kernel, hpa, mingo, peterz, rmk+kernel, sruffell, paulmck,
tglx, venki
Commit-ID: 2d513868e2a33e1d5315490ef4c861ee65babd65
Gitweb: http://git.kernel.org/tip/2d513868e2a33e1d5315490ef4c861ee65babd65
Author: Thomas Gleixner <tglx@linutronix.de>
AuthorDate: Fri, 2 May 2014 23:26:24 +0200
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Wed, 7 May 2014 11:51:30 +0200
sched: Sanitize irq accounting madness
Russell reported, that irqtime_account_idle_ticks() takes ages due to:
for (i = 0; i < ticks; i++)
irqtime_account_process_tick(current, 0, rq);
It's sad, that this code was written way _AFTER_ the NOHZ idle
functionality was available. I charge myself guitly for not paying
attention when that crap got merged with commit abb74cefa ("sched:
Export ns irqtimes through /proc/stat")
So instead of looping nr_ticks times just apply the whole thing at
once.
As a side note: The whole cputime_t vs. u64 business in that context
wants to be cleaned up as well. There is no point in having all these
back and forth conversions. Lets standardise on u64 nsec for all
kernel internal accounting and be done with it. Everything else does
not make sense at all for fine grained accounting. Frederic, can you
please take care of that?
Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Venkatesh Pallipadi <venki@google.com>
Cc: Shaun Ruffell <sruffell@digium.com>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/alpine.DEB.2.02.1405022307000.6261@ionos.tec.linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
kernel/sched/cputime.c | 32 ++++++++++++++++----------------
1 file changed, 16 insertions(+), 16 deletions(-)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index a95097c..72fdf06 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -332,50 +332,50 @@ out:
* softirq as those do not count in task exec_runtime any more.
*/
static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
- struct rq *rq)
+ struct rq *rq, int ticks)
{
- cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
+ cputime_t scaled = cputime_to_scaled(cputime_one_jiffy);
+ u64 cputime = (__force u64) cputime_one_jiffy;
u64 *cpustat = kcpustat_this_cpu->cpustat;
if (steal_account_process_tick())
return;
+ cputime *= ticks;
+ scaled *= ticks;
+
if (irqtime_account_hi_update()) {
- cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
+ cpustat[CPUTIME_IRQ] += cputime;
} else if (irqtime_account_si_update()) {
- cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
+ cpustat[CPUTIME_SOFTIRQ] += cputime;
} else if (this_cpu_ksoftirqd() == p) {
/*
* ksoftirqd time do not get accounted in cpu_softirq_time.
* So, we have to handle it separately here.
* Also, p->stime needs to be updated for ksoftirqd.
*/
- __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
- CPUTIME_SOFTIRQ);
+ __account_system_time(p, cputime, scaled, CPUTIME_SOFTIRQ);
} else if (user_tick) {
- account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
+ account_user_time(p, cputime, scaled);
} else if (p == rq->idle) {
- account_idle_time(cputime_one_jiffy);
+ account_idle_time(cputime);
} else if (p->flags & PF_VCPU) { /* System time or guest time */
- account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
+ account_guest_time(p, cputime, scaled);
} else {
- __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
- CPUTIME_SYSTEM);
+ __account_system_time(p, cputime, scaled, CPUTIME_SYSTEM);
}
}
static void irqtime_account_idle_ticks(int ticks)
{
- int i;
struct rq *rq = this_rq();
- for (i = 0; i < ticks; i++)
- irqtime_account_process_tick(current, 0, rq);
+ irqtime_account_process_tick(current, 0, rq, ticks);
}
#else /* CONFIG_IRQ_TIME_ACCOUNTING */
static inline void irqtime_account_idle_ticks(int ticks) {}
static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
- struct rq *rq) {}
+ struct rq *rq, int nr_ticks) {}
#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
/*
@@ -464,7 +464,7 @@ void account_process_tick(struct task_struct *p, int user_tick)
return;
if (sched_clock_irqtime) {
- irqtime_account_process_tick(p, user_tick, rq);
+ irqtime_account_process_tick(p, user_tick, rq, 1);
return;
}
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] sched: Sanitize irq accounting madness
2014-05-02 21:26 [PATCH] sched: Sanitize irq accounting madness Thomas Gleixner
2014-05-02 21:38 ` Paul E. McKenney
2014-05-08 10:41 ` [tip:sched/core] " tip-bot for Thomas Gleixner
@ 2014-07-09 16:24 ` Frederic Weisbecker
2 siblings, 0 replies; 4+ messages in thread
From: Frederic Weisbecker @ 2014-07-09 16:24 UTC (permalink / raw)
To: Thomas Gleixner
Cc: LKML, Russell King, Ingo Molnar, H. Peter Anvin, Peter Zijlstra,
Venkatesh Pallipadi, Paul E. McKenney
On Fri, May 02, 2014 at 11:26:24PM +0200, Thomas Gleixner wrote:
> Russell reported, that irqtime_account_idle_ticks() takes ages due to:
>
> for (i = 0; i < ticks; i++)
> irqtime_account_process_tick(current, 0, rq);
>
> It's sad, that this code was written way _AFTER_ the NOHZ idle
> functionality was available. I charge myself guitly for not paying
> attention when that crap got merged with commit abb74cefa (sched:
> Export ns irqtimes through /proc/stat)
>
> So instead of looping nr_ticks times just apply the whole thing at
> once.
>
> As a side note: The whole cputime_t vs. u64 business in that context
> wants to be cleaned up as well. There is no point in having all these
> back and forth conversions. Lets standardise on u64 nsec for all
> kernel internal accounting and be done with it. Everything else does
> not make sense at all for fine grained accounting. Frederic, can you
> please take care of that?
Oops I missed that. Yeah I can try something to that direction.
Thanks.
>
> Reported-by: Russell King <rmk+kernel@arm.linux.org.uk>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: stable@vger.kernel.org
> ---
> kernel/sched/cputime.c | 32 ++++++++++++++++----------------
> 1 file changed, 16 insertions(+), 16 deletions(-)
>
> Index: linux-2.6/kernel/sched/cputime.c
> ===================================================================
> --- linux-2.6.orig/kernel/sched/cputime.c
> +++ linux-2.6/kernel/sched/cputime.c
> @@ -332,50 +332,50 @@ out:
> * softirq as those do not count in task exec_runtime any more.
> */
> static void irqtime_account_process_tick(struct task_struct *p, int user_tick,
> - struct rq *rq)
> + struct rq *rq, int ticks)
> {
> - cputime_t one_jiffy_scaled = cputime_to_scaled(cputime_one_jiffy);
> + cputime_t scaled = cputime_to_scaled(cputime_one_jiffy);
> + u64 cputime = (__force u64) cputime_one_jiffy;
> u64 *cpustat = kcpustat_this_cpu->cpustat;
>
> if (steal_account_process_tick())
> return;
>
> + cputime *= ticks;
> + scaled *= ticks;
> +
> if (irqtime_account_hi_update()) {
> - cpustat[CPUTIME_IRQ] += (__force u64) cputime_one_jiffy;
> + cpustat[CPUTIME_IRQ] += cputime;
> } else if (irqtime_account_si_update()) {
> - cpustat[CPUTIME_SOFTIRQ] += (__force u64) cputime_one_jiffy;
> + cpustat[CPUTIME_SOFTIRQ] += cputime;
> } else if (this_cpu_ksoftirqd() == p) {
> /*
> * ksoftirqd time do not get accounted in cpu_softirq_time.
> * So, we have to handle it separately here.
> * Also, p->stime needs to be updated for ksoftirqd.
> */
> - __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
> - CPUTIME_SOFTIRQ);
> + __account_system_time(p, cputime, scaled, CPUTIME_SOFTIRQ);
> } else if (user_tick) {
> - account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
> + account_user_time(p, cputime, scaled);
> } else if (p == rq->idle) {
> - account_idle_time(cputime_one_jiffy);
> + account_idle_time(cputime);
> } else if (p->flags & PF_VCPU) { /* System time or guest time */
> - account_guest_time(p, cputime_one_jiffy, one_jiffy_scaled);
> + account_guest_time(p, cputime, scaled);
> } else {
> - __account_system_time(p, cputime_one_jiffy, one_jiffy_scaled,
> - CPUTIME_SYSTEM);
> + __account_system_time(p, cputime, scaled, CPUTIME_SYSTEM);
> }
> }
>
> static void irqtime_account_idle_ticks(int ticks)
> {
> - int i;
> struct rq *rq = this_rq();
>
> - for (i = 0; i < ticks; i++)
> - irqtime_account_process_tick(current, 0, rq);
> + irqtime_account_process_tick(current, 0, rq, ticks);
> }
> #else /* CONFIG_IRQ_TIME_ACCOUNTING */
> static inline void irqtime_account_idle_ticks(int ticks) {}
> static inline void irqtime_account_process_tick(struct task_struct *p, int user_tick,
> - struct rq *rq) {}
> + struct rq *rq, int nr_ticks) {}
> #endif /* CONFIG_IRQ_TIME_ACCOUNTING */
>
> /*
> @@ -464,7 +464,7 @@ void account_process_tick(struct task_st
> return;
>
> if (sched_clock_irqtime) {
> - irqtime_account_process_tick(p, user_tick, rq);
> + irqtime_account_process_tick(p, user_tick, rq, 1);
> return;
> }
>
^ permalink raw reply [flat|nested] 4+ messages in thread