* [PATCH v2] sched/cputime: add steal time support to full dynticks CPU time accounting
@ 2016-05-18 8:28 Wanpeng Li
2016-05-18 9:46 ` Mika Penttilä
0 siblings, 1 reply; 3+ messages in thread
From: Wanpeng Li @ 2016-05-18 8:28 UTC (permalink / raw)
To: linux-kernel, kvm
Cc: Wanpeng Li, Ingo Molnar, Peter Zijlstra (Intel), Rik van Riel,
Thomas Gleixner, Frederic Weisbecker, Paolo Bonzini, Radim
From: Wanpeng Li <wanpeng.li@hotmail.com>
This patch adds steal guest time support to full dynticks CPU
time accounting. After 'commit ff9a9b4c4334 ("sched, time: Switch
VIRT_CPU_ACCOUNTING_GEN to jiffy granularity")', time is jiffy
based sampling even if it's still listened to ring boundaries, so
steal_account_process_tick() is reused to account how much 'ticks'
are steal time after the last accumulation.
Suggested-by: Rik van Riel <riel@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim <rkrcmar@redhat.com>
Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
---
v1 -> v2:
* fix divide zero bug, thanks Rik
kernel/sched/cputime.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
index 75f98c5..bfa50a0 100644
--- a/kernel/sched/cputime.c
+++ b/kernel/sched/cputime.c
@@ -257,7 +257,7 @@ void account_idle_time(cputime_t cputime)
cpustat[CPUTIME_IDLE] += (__force u64) cputime;
}
-static __always_inline bool steal_account_process_tick(void)
+static __always_inline unsigned long steal_account_process_tick(void)
{
#ifdef CONFIG_PARAVIRT
if (static_key_false(¶virt_steal_enabled)) {
@@ -279,7 +279,7 @@ static __always_inline bool steal_account_process_tick(void)
return steal_jiffies;
}
#endif
- return false;
+ return 0;
}
/*
@@ -691,8 +691,12 @@ static cputime_t get_vtime_delta(struct task_struct *tsk)
static void __vtime_account_system(struct task_struct *tsk)
{
+ unsigned long steal_time = steal_account_process_tick();
cputime_t delta_cpu = get_vtime_delta(tsk);
+ if (steal_time >= delta_cpu)
+ return;
+ delta_cpu -= steal_time;
account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
}
@@ -723,7 +727,12 @@ void vtime_account_user(struct task_struct *tsk)
write_seqcount_begin(&tsk->vtime_seqcount);
tsk->vtime_snap_whence = VTIME_SYS;
if (vtime_delta(tsk)) {
+ unsigned long steal_time = steal_account_process_tick();
delta_cpu = get_vtime_delta(tsk);
+
+ if (steal_time >= delta_cpu)
+ return;
+ delta_cpu -= steal_time;
account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
}
write_seqcount_end(&tsk->vtime_seqcount);
--
1.9.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH v2] sched/cputime: add steal time support to full dynticks CPU time accounting
2016-05-18 8:28 [PATCH v2] sched/cputime: add steal time support to full dynticks CPU time accounting Wanpeng Li
@ 2016-05-18 9:46 ` Mika Penttilä
2016-05-18 10:06 ` Wanpeng Li
0 siblings, 1 reply; 3+ messages in thread
From: Mika Penttilä @ 2016-05-18 9:46 UTC (permalink / raw)
To: Wanpeng Li, linux-kernel, kvm
Cc: Wanpeng Li, Ingo Molnar, Peter Zijlstra (Intel), Rik van Riel,
Thomas Gleixner, Frederic Weisbecker, Paolo Bonzini, Radim
On 05/18/2016 11:28 AM, Wanpeng Li wrote:
> From: Wanpeng Li <wanpeng.li@hotmail.com>
>
> This patch adds steal guest time support to full dynticks CPU
> time accounting. After 'commit ff9a9b4c4334 ("sched, time: Switch
> VIRT_CPU_ACCOUNTING_GEN to jiffy granularity")', time is jiffy
> based sampling even if it's still listened to ring boundaries, so
> steal_account_process_tick() is reused to account how much 'ticks'
> are steal time after the last accumulation.
>
> Suggested-by: Rik van Riel <riel@redhat.com>
> Cc: Ingo Molnar <mingo@kernel.org>
> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Frederic Weisbecker <fweisbec@gmail.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Radim <rkrcmar@redhat.com>
> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
> ---
> v1 -> v2:
> * fix divide zero bug, thanks Rik
>
> kernel/sched/cputime.c | 13 +++++++++++--
> 1 file changed, 11 insertions(+), 2 deletions(-)
>
> diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
> index 75f98c5..bfa50a0 100644
> --- a/kernel/sched/cputime.c
> +++ b/kernel/sched/cputime.c
> @@ -257,7 +257,7 @@ void account_idle_time(cputime_t cputime)
> cpustat[CPUTIME_IDLE] += (__force u64) cputime;
> }
>
> -static __always_inline bool steal_account_process_tick(void)
> +static __always_inline unsigned long steal_account_process_tick(void)
> {
> #ifdef CONFIG_PARAVIRT
> if (static_key_false(¶virt_steal_enabled)) {
> @@ -279,7 +279,7 @@ static __always_inline bool steal_account_process_tick(void)
> return steal_jiffies;
> }
> #endif
> - return false;
> + return 0;
> }
>
> /*
> @@ -691,8 +691,12 @@ static cputime_t get_vtime_delta(struct task_struct *tsk)
>
> static void __vtime_account_system(struct task_struct *tsk)
> {
> + unsigned long steal_time = steal_account_process_tick();
> cputime_t delta_cpu = get_vtime_delta(tsk);
>
> + if (steal_time >= delta_cpu)
> + return;
> + delta_cpu -= steal_time;
> account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
> }
>
> @@ -723,7 +727,12 @@ void vtime_account_user(struct task_struct *tsk)
> write_seqcount_begin(&tsk->vtime_seqcount);
> tsk->vtime_snap_whence = VTIME_SYS;
> if (vtime_delta(tsk)) {
> + unsigned long steal_time = steal_account_process_tick();
> delta_cpu = get_vtime_delta(tsk);
afaik steal_account_process_tick() returns jiffies and get_vtime_delta() cputime, so can't mix them like this : ?
> +
> + if (steal_time >= delta_cpu)
> + return;
> + delta_cpu -= steal_time;
> account_user_time(tsk, delta_cpu, cputime_to_scaled(delta_cpu));
> }
> write_seqcount_end(&tsk->vtime_seqcount);
>
--Mika
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH v2] sched/cputime: add steal time support to full dynticks CPU time accounting
2016-05-18 9:46 ` Mika Penttilä
@ 2016-05-18 10:06 ` Wanpeng Li
0 siblings, 0 replies; 3+ messages in thread
From: Wanpeng Li @ 2016-05-18 10:06 UTC (permalink / raw)
To: Mika Penttilä
Cc: linux-kernel@vger.kernel.org, kvm, Wanpeng Li, Ingo Molnar,
Peter Zijlstra (Intel), Rik van Riel, Thomas Gleixner,
Frederic Weisbecker, Paolo Bonzini, Radim
2016-05-18 17:46 GMT+08:00 Mika Penttilä <mika.penttila@nextfour.com>:
> On 05/18/2016 11:28 AM, Wanpeng Li wrote:
>> From: Wanpeng Li <wanpeng.li@hotmail.com>
>>
>> This patch adds steal guest time support to full dynticks CPU
>> time accounting. After 'commit ff9a9b4c4334 ("sched, time: Switch
>> VIRT_CPU_ACCOUNTING_GEN to jiffy granularity")', time is jiffy
>> based sampling even if it's still listened to ring boundaries, so
>> steal_account_process_tick() is reused to account how much 'ticks'
>> are steal time after the last accumulation.
>>
>> Suggested-by: Rik van Riel <riel@redhat.com>
>> Cc: Ingo Molnar <mingo@kernel.org>
>> Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
>> Cc: Rik van Riel <riel@redhat.com>
>> Cc: Thomas Gleixner <tglx@linutronix.de>
>> Cc: Frederic Weisbecker <fweisbec@gmail.com>
>> Cc: Paolo Bonzini <pbonzini@redhat.com>
>> Cc: Radim <rkrcmar@redhat.com>
>> Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
>> ---
>> v1 -> v2:
>> * fix divide zero bug, thanks Rik
>>
>> kernel/sched/cputime.c | 13 +++++++++++--
>> 1 file changed, 11 insertions(+), 2 deletions(-)
>>
>> diff --git a/kernel/sched/cputime.c b/kernel/sched/cputime.c
>> index 75f98c5..bfa50a0 100644
>> --- a/kernel/sched/cputime.c
>> +++ b/kernel/sched/cputime.c
>> @@ -257,7 +257,7 @@ void account_idle_time(cputime_t cputime)
>> cpustat[CPUTIME_IDLE] += (__force u64) cputime;
>> }
>>
>> -static __always_inline bool steal_account_process_tick(void)
>> +static __always_inline unsigned long steal_account_process_tick(void)
>> {
>> #ifdef CONFIG_PARAVIRT
>> if (static_key_false(¶virt_steal_enabled)) {
>> @@ -279,7 +279,7 @@ static __always_inline bool steal_account_process_tick(void)
>> return steal_jiffies;
>> }
>> #endif
>> - return false;
>> + return 0;
>> }
>>
>> /*
>> @@ -691,8 +691,12 @@ static cputime_t get_vtime_delta(struct task_struct *tsk)
>>
>> static void __vtime_account_system(struct task_struct *tsk)
>> {
>> + unsigned long steal_time = steal_account_process_tick();
>> cputime_t delta_cpu = get_vtime_delta(tsk);
>>
>> + if (steal_time >= delta_cpu)
>> + return;
>> + delta_cpu -= steal_time;
>> account_system_time(tsk, irq_count(), delta_cpu, cputime_to_scaled(delta_cpu));
>> }
>>
>> @@ -723,7 +727,12 @@ void vtime_account_user(struct task_struct *tsk)
>> write_seqcount_begin(&tsk->vtime_seqcount);
>> tsk->vtime_snap_whence = VTIME_SYS;
>> if (vtime_delta(tsk)) {
>> + unsigned long steal_time = steal_account_process_tick();
>> delta_cpu = get_vtime_delta(tsk);
>
>
> afaik steal_account_process_tick() returns jiffies and get_vtime_delta() cputime, so can't mix them like this : ?
You are right, thanks for your review. I will fix it.
Regards,
Wanpeng Li
^ permalink raw reply [flat|nested] 3+ messages in thread
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2016-05-18 8:28 [PATCH v2] sched/cputime: add steal time support to full dynticks CPU time accounting Wanpeng Li
2016-05-18 9:46 ` Mika Penttilä
2016-05-18 10:06 ` Wanpeng Li
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