[PATCH 1/4] fix scaled & unscaled cputime accounting

From: Jayson R. King
Date: Mon Oct 05 2009 - 06:30:44 EST

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From: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

[upstream commit 457533a7d3402d1d91fbc125c8bd1bd16dcd3cd4]

The utimescaled / stimescaled fields in the task structure and the
global cpustat should be set on all architectures. On s390 the calls
to account_user_time_scaled and account_system_time_scaled never have
been added. In addition system time that is accounted as guest time
to the user time of a process is accounted to the scaled system time
instead of the scaled user time.
To fix the bugs and to prevent future forgetfulness this patch merges
account_system_time_scaled into account_system_time and
account_user_time_scaled into account_user_time.

Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Hidetoshi Seto <seto.hidetoshi@xxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxxxxxxx>
Cc: Chris Wright <chrisw@xxxxxxxxxxxx>
Cc: Michael Neuling <mikey@xxxxxxxxxxx>
Acked-by: Paul Mackerras <paulus@xxxxxxxxx>
Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

---
arch/ia64/kernel/time.c | 12 +++------
arch/powerpc/kernel/time.c | 7 +----
arch/s390/kernel/vtime.c | 10 ++++----
include/linux/kernel_stat.h | 6 +---
kernel/sched.c | 41 +++++++++++++---------------------
kernel/time/tick-sched.c | 5 ++--
kernel/timer.c | 12 ++++-----
7 files changed, 37 insertions(+), 56 deletions(-)

diff -udrNp linux-2.6.27.orig/arch/ia64/kernel/time.c linux-2.6.27/arch/ia64/kernel/time.c
--- linux-2.6.27.orig/arch/ia64/kernel/time.c 2008-10-09 17:13:53.000000000 -0500
+++ linux-2.6.27/arch/ia64/kernel/time.c 2009-10-02 05:08:10.543580236 -0500
@@ -93,13 +93,11 @@ void ia64_account_on_switch(struct task_
now = ia64_get_itc();

delta_stime = cycle_to_cputime(pi->ac_stime + (now - pi->ac_stamp));
- account_system_time(prev, 0, delta_stime);
- account_system_time_scaled(prev, delta_stime);
+ account_system_time(prev, 0, delta_stime, delta_stime);

if (pi->ac_utime) {
delta_utime = cycle_to_cputime(pi->ac_utime);
- account_user_time(prev, delta_utime);
- account_user_time_scaled(prev, delta_utime);
+ account_user_time(prev, delta_utime, delta_utime);
}

pi->ac_stamp = ni->ac_stamp = now;
@@ -122,8 +120,7 @@ void account_system_vtime(struct task_st
now = ia64_get_itc();

delta_stime = cycle_to_cputime(ti->ac_stime + (now - ti->ac_stamp));
- account_system_time(tsk, 0, delta_stime);
- account_system_time_scaled(tsk, delta_stime);
+ account_system_time(tsk, 0, delta_stime, delta_stime);
ti->ac_stime = 0;

ti->ac_stamp = now;
@@ -143,8 +140,7 @@ void account_process_tick(struct task_st

if (ti->ac_utime) {
delta_utime = cycle_to_cputime(ti->ac_utime);
- account_user_time(p, delta_utime);
- account_user_time_scaled(p, delta_utime);
+ account_user_time(p, delta_utime, delta_utime);
ti->ac_utime = 0;
}
}
diff -udrNp linux-2.6.27.orig/arch/powerpc/kernel/time.c linux-2.6.27/arch/powerpc/kernel/time.c
--- linux-2.6.27.orig/arch/powerpc/kernel/time.c 2008-10-09 17:13:53.000000000 -0500
+++ linux-2.6.27/arch/powerpc/kernel/time.c 2009-10-02 05:08:10.543580236 -0500
@@ -258,8 +258,7 @@ void account_system_vtime(struct task_st
delta += sys_time;
get_paca()->system_time = 0;
}
- account_system_time(tsk, 0, delta);
- account_system_time_scaled(tsk, deltascaled);
+ account_system_time(tsk, 0, delta, deltascaled);
per_cpu(cputime_last_delta, smp_processor_id()) = delta;
per_cpu(cputime_scaled_last_delta, smp_processor_id()) = deltascaled;
local_irq_restore(flags);
@@ -277,10 +276,8 @@ void account_process_tick(struct task_st

utime = get_paca()->user_time;
get_paca()->user_time = 0;
- account_user_time(tsk, utime);
-
utimescaled = cputime_to_scaled(utime);
- account_user_time_scaled(tsk, utimescaled);
+ account_user_time(tsk, utime, utimescaled);
}

/*
diff -udrNp linux-2.6.27.orig/arch/s390/kernel/vtime.c linux-2.6.27/arch/s390/kernel/vtime.c
--- linux-2.6.27.orig/arch/s390/kernel/vtime.c 2008-10-09 17:13:53.000000000 -0500
+++ linux-2.6.27/arch/s390/kernel/vtime.c 2009-10-02 05:08:10.543580236 -0500
@@ -51,12 +51,12 @@ void account_process_tick(struct task_st
rcu_user_flag = cputime != 0;
S390_lowcore.user_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
- account_user_time(tsk, cputime);
+ account_user_time(tsk, cputime, cputime);

cputime = S390_lowcore.system_timer >> 12;
S390_lowcore.system_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
- account_system_time(tsk, HARDIRQ_OFFSET, cputime);
+ account_system_time(tsk, HARDIRQ_OFFSET, cputime, cputime);

cputime = S390_lowcore.steal_clock;
if ((__s64) cputime > 0) {
@@ -83,12 +83,12 @@ void account_vtime(struct task_struct *t
cputime = S390_lowcore.user_timer >> 12;
S390_lowcore.user_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
- account_user_time(tsk, cputime);
+ account_user_time(tsk, cputime, cputime);

cputime = S390_lowcore.system_timer >> 12;
S390_lowcore.system_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
- account_system_time(tsk, 0, cputime);
+ account_system_time(tsk, 0, cputime, cputime);
}

/*
@@ -108,7 +108,7 @@ void account_system_vtime(struct task_st
cputime = S390_lowcore.system_timer >> 12;
S390_lowcore.system_timer -= cputime << 12;
S390_lowcore.steal_clock -= cputime << 12;
- account_system_time(tsk, 0, cputime);
+ account_system_time(tsk, 0, cputime, cputime);
}
EXPORT_SYMBOL_GPL(account_system_vtime);

diff -udrNp linux-2.6.27.orig/include/linux/kernel_stat.h linux-2.6.27/include/linux/kernel_stat.h
--- linux-2.6.27.orig/include/linux/kernel_stat.h 2008-10-09 17:13:53.000000000 -0500
+++ linux-2.6.27/include/linux/kernel_stat.h 2009-10-02 05:08:10.543580236 -0500
@@ -52,10 +52,8 @@ static inline int kstat_irqs(int irq)
return sum;
}

-extern void account_user_time(struct task_struct *, cputime_t);
-extern void account_user_time_scaled(struct task_struct *, cputime_t);
-extern void account_system_time(struct task_struct *, int, cputime_t);
-extern void account_system_time_scaled(struct task_struct *, cputime_t);
+extern void account_user_time(struct task_struct *, cputime_t, cputime_t);
+extern void account_system_time(struct task_struct *, int, cputime_t, cputime_t);
extern void account_steal_time(struct task_struct *, cputime_t);

#endif /* _LINUX_KERNEL_STAT_H */
diff -udrNp linux-2.6.27.orig/kernel/sched.c linux-2.6.27/kernel/sched.c
--- linux-2.6.27.orig/kernel/sched.c 2009-10-02 05:07:46.098579687 -0500
+++ linux-2.6.27/kernel/sched.c 2009-10-02 05:08:10.545579395 -0500
@@ -4063,13 +4063,17 @@ unsigned long long task_sched_runtime(st
* Account user cpu time to a process.
* @p: the process that the cpu time gets accounted to
* @cputime: the cpu time spent in user space since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
*/
-void account_user_time(struct task_struct *p, cputime_t cputime)
+void account_user_time(struct task_struct *p, cputime_t cputime,
+ cputime_t cputime_scaled)
{
struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
cputime64_t tmp;

+ /* Add user time to process. */
p->utime = cputime_add(p->utime, cputime);
+ p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);

/* Add user time to cpustat. */
tmp = cputime_to_cputime64(cputime);
@@ -4085,50 +4089,48 @@ void account_user_time(struct task_struc
* Account guest cpu time to a process.
* @p: the process that the cpu time gets accounted to
* @cputime: the cpu time spent in virtual machine since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
*/
-static void account_guest_time(struct task_struct *p, cputime_t cputime)
+static void account_guest_time(struct task_struct *p, cputime_t cputime,
+ cputime_t cputime_scaled)
{
cputime64_t tmp;
struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;

tmp = cputime_to_cputime64(cputime);

+ /* Add guest time to process. */
p->utime = cputime_add(p->utime, cputime);
+ p->utimescaled = cputime_add(p->utimescaled, cputime_scaled);
p->gtime = cputime_add(p->gtime, cputime);

+ /* Add guest time to cpustat. */
cpustat->user = cputime64_add(cpustat->user, tmp);
cpustat->guest = cputime64_add(cpustat->guest, tmp);
}

/*
- * Account scaled user cpu time to a process.
- * @p: the process that the cpu time gets accounted to
- * @cputime: the cpu time spent in user space since the last update
- */
-void account_user_time_scaled(struct task_struct *p, cputime_t cputime)
-{
- p->utimescaled = cputime_add(p->utimescaled, cputime);
-}
-
-/*
* Account system cpu time to a process.
* @p: the process that the cpu time gets accounted to
* @hardirq_offset: the offset to subtract from hardirq_count()
* @cputime: the cpu time spent in kernel space since the last update
+ * @cputime_scaled: cputime scaled by cpu frequency
*/
void account_system_time(struct task_struct *p, int hardirq_offset,
- cputime_t cputime)
+ cputime_t cputime, cputime_t cputime_scaled)
{
struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat;
struct rq *rq = this_rq();
cputime64_t tmp;

if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) {
- account_guest_time(p, cputime);
+ account_guest_time(p, cputime, cputime_scaled);
return;
}

+ /* Add system time to process. */
p->stime = cputime_add(p->stime, cputime);
+ p->stimescaled = cputime_add(p->stimescaled, cputime_scaled);

/* Add system time to cpustat. */
tmp = cputime_to_cputime64(cputime);
@@ -4147,17 +4149,6 @@ void account_system_time(struct task_str
}

/*
- * Account scaled system cpu time to a process.
- * @p: the process that the cpu time gets accounted to
- * @hardirq_offset: the offset to subtract from hardirq_count()
- * @cputime: the cpu time spent in kernel space since the last update
- */
-void account_system_time_scaled(struct task_struct *p, cputime_t cputime)
-{
- p->stimescaled = cputime_add(p->stimescaled, cputime);
-}
-
-/*
* Account for involuntary wait time.
* @p: the process from which the cpu time has been stolen
* @steal: the cpu time spent in involuntary wait
diff -udrNp linux-2.6.27.orig/kernel/time/tick-sched.c linux-2.6.27/kernel/time/tick-sched.c
--- linux-2.6.27.orig/kernel/time/tick-sched.c 2008-10-09 17:13:53.000000000 -0500
+++ linux-2.6.27/kernel/time/tick-sched.c 2009-10-02 05:08:10.546579540 -0500
@@ -378,6 +378,7 @@ void tick_nohz_restart_sched_tick(void)
int cpu = smp_processor_id();
struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
unsigned long ticks;
+ cputime_t cputime;
ktime_t now;

local_irq_disable();
@@ -410,8 +411,8 @@ void tick_nohz_restart_sched_tick(void)
*/
if (ticks && ticks < LONG_MAX) {
add_preempt_count(HARDIRQ_OFFSET);
- account_system_time(current, HARDIRQ_OFFSET,
- jiffies_to_cputime(ticks));
+ cputime = jiffies_to_cputime(ticks);
+ account_system_time(current, HARDIRQ_OFFSET, cputime, cputime);
sub_preempt_count(HARDIRQ_OFFSET);
}

diff -udrNp linux-2.6.27.orig/kernel/timer.c linux-2.6.27/kernel/timer.c
--- linux-2.6.27.orig/kernel/timer.c 2009-10-02 05:07:46.108579580 -0500
+++ linux-2.6.27/kernel/timer.c 2009-10-02 05:08:10.546579540 -0500
@@ -954,13 +954,11 @@ void account_process_tick(struct task_st
{
cputime_t one_jiffy = jiffies_to_cputime(1);

- if (user_tick) {
- account_user_time(p, one_jiffy);
- account_user_time_scaled(p, cputime_to_scaled(one_jiffy));
- } else {
- account_system_time(p, HARDIRQ_OFFSET, one_jiffy);
- account_system_time_scaled(p, cputime_to_scaled(one_jiffy));
- }
+ if (user_tick)
+ account_user_time(p, one_jiffy, cputime_to_scaled(one_jiffy));
+ else
+ account_system_time(p, HARDIRQ_OFFSET, one_jiffy,
+ cputime_to_scaled(one_jiffy));
}
#endif

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Next message: Jayson R. King: "[PATCH 2/4] idle cputime accounting"
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