Re: [PATCH v5 7/9] KVM-GST: KVM Steal time accounting
On 07/04/2011 11:32 AM, Glauber Costa wrote: This patch accounts steal time time in account_process_tick. If one or more tick is considered stolen in the current accounting cycle, user/system accounting is skipped. Idle is fine, since the hypervisor does not report steal time if the guest is halted. Accounting steal time from the core scheduler give us the advantage of direct acess to the runqueue data. In a later opportunity, it can be used to tweak cpu power and make the scheduler aware of the time it lost. Signed-off-by: Glauber Costaglom...@redhat.com CC: Rik van Rielr...@redhat.com CC: Jeremy Fitzhardingejeremy.fitzhardi...@citrix.com CC: Peter Zijlstrapet...@infradead.org CC: Avi Kivitya...@redhat.com CC: Anthony Liguorialigu...@us.ibm.com CC: Eric B Munsonemun...@mgebm.net Acked-by: Rik van Riel r...@redhat.com -- All rights reversed -- To unsubscribe from this list: send the line unsubscribe kvm in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: [PATCH v5 7/9] KVM-GST: KVM Steal time accounting
On Mon, 2011-07-04 at 11:32 -0400, Glauber Costa wrote:
This patch accounts steal time time in account_process_tick.
If one or more tick is considered stolen in the current
accounting cycle, user/system accounting is skipped. Idle is fine,
since the hypervisor does not report steal time if the guest
is halted.
Accounting steal time from the core scheduler give us the
advantage of direct acess to the runqueue data. In a later
opportunity, it can be used to tweak cpu power and make
the scheduler aware of the time it lost.
Signed-off-by: Glauber Costa glom...@redhat.com
CC: Rik van Riel r...@redhat.com
CC: Jeremy Fitzhardinge jeremy.fitzhardi...@citrix.com
Acked-by: Peter Zijlstra pet...@infradead.org
Venki, can you have a look at that irqtime_account_process_tick(), I
think adding the steal time up front like this is fine, because it
suffers from the same 'problem' as both irqtime thingies.
CC: Avi Kivity a...@redhat.com
CC: Anthony Liguori aligu...@us.ibm.com
CC: Eric B Munson emun...@mgebm.net
---
kernel/sched.c | 41 +
1 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 3f2e502..aa6c030 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -75,6 +75,7 @@
#include asm/tlb.h
#include asm/irq_regs.h
#include asm/mutex.h
+#include asm/paravirt.h
#include sched_cpupri.h
#include workqueue_sched.h
@@ -528,6 +529,9 @@ struct rq {
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
u64 prev_irq_time;
#endif
+#ifdef CONFIG_PARAVIRT
+ u64 prev_steal_time;
+#endif
/* calc_load related fields */
unsigned long calc_load_update;
@@ -1953,6 +1957,18 @@ void account_system_vtime(struct task_struct *curr)
}
EXPORT_SYMBOL_GPL(account_system_vtime);
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#ifdef CONFIG_PARAVIRT
+static inline u64 steal_ticks(u64 steal)
+{
+ if (unlikely(steal NSEC_PER_SEC))
+ return div_u64(steal, TICK_NSEC);
+
+ return __iter_div_u64_rem(steal, TICK_NSEC, steal);
+}
+#endif
+
static void update_rq_clock_task(struct rq *rq, s64 delta)
{
s64 irq_delta;
@@ -3845,6 +3861,25 @@ void account_idle_time(cputime_t cputime)
cpustat-idle = cputime64_add(cpustat-idle, cputime64);
}
+static __always_inline bool steal_account_process_tick(void)
+{
+#ifdef CONFIG_PARAVIRT
+ if (static_branch(paravirt_steal_enabled)) {
+ u64 steal, st = 0;
+
+ steal = paravirt_steal_clock(smp_processor_id());
+ steal -= this_rq()-prev_steal_time;
+
+ st = steal_ticks(steal);
+ this_rq()-prev_steal_time += st * TICK_NSEC;
+
+ account_steal_time(st);
+ return st;
+ }
+#endif
+ return false;
+}
+
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
@@ -3876,6 +3911,9 @@ static void irqtime_account_process_tick(struct
task_struct *p, int user_tick,
cputime64_t tmp = cputime_to_cputime64(cputime_one_jiffy);
struct cpu_usage_stat *cpustat = kstat_this_cpu.cpustat;
+ if (steal_account_process_tick())
+ return;
+
if (irqtime_account_hi_update()) {
cpustat-irq = cputime64_add(cpustat-irq, tmp);
} else if (irqtime_account_si_update()) {
@@ -3929,6 +3967,9 @@ void account_process_tick(struct task_struct *p, int
user_tick)
return;
}
+ if (steal_account_process_tick())
+ return;
+
if (user_tick)
account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
else if ((p != rq-idle) || (irq_count() != HARDIRQ_OFFSET))
--
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Re: [PATCH v5 7/9] KVM-GST: KVM Steal time accounting
On Mon, 04 Jul 2011, Glauber Costa wrote: This patch accounts steal time time in account_process_tick. If one or more tick is considered stolen in the current accounting cycle, user/system accounting is skipped. Idle is fine, since the hypervisor does not report steal time if the guest is halted. Accounting steal time from the core scheduler give us the advantage of direct acess to the runqueue data. In a later opportunity, it can be used to tweak cpu power and make the scheduler aware of the time it lost. Signed-off-by: Glauber Costa glom...@redhat.com CC: Rik van Riel r...@redhat.com CC: Jeremy Fitzhardinge jeremy.fitzhardi...@citrix.com CC: Peter Zijlstra pet...@infradead.org CC: Avi Kivity a...@redhat.com CC: Anthony Liguori aligu...@us.ibm.com CC: Eric B Munson emun...@mgebm.net Tested-by: Eric B Munson emun...@mgebm.net signature.asc Description: Digital signature
[PATCH v5 7/9] KVM-GST: KVM Steal time accounting
This patch accounts steal time time in account_process_tick.
If one or more tick is considered stolen in the current
accounting cycle, user/system accounting is skipped. Idle is fine,
since the hypervisor does not report steal time if the guest
is halted.
Accounting steal time from the core scheduler give us the
advantage of direct acess to the runqueue data. In a later
opportunity, it can be used to tweak cpu power and make
the scheduler aware of the time it lost.
Signed-off-by: Glauber Costa glom...@redhat.com
CC: Rik van Riel r...@redhat.com
CC: Jeremy Fitzhardinge jeremy.fitzhardi...@citrix.com
CC: Peter Zijlstra pet...@infradead.org
CC: Avi Kivity a...@redhat.com
CC: Anthony Liguori aligu...@us.ibm.com
CC: Eric B Munson emun...@mgebm.net
---
kernel/sched.c | 41 +
1 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/kernel/sched.c b/kernel/sched.c
index 3f2e502..aa6c030 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -75,6 +75,7 @@
#include asm/tlb.h
#include asm/irq_regs.h
#include asm/mutex.h
+#include asm/paravirt.h
#include sched_cpupri.h
#include workqueue_sched.h
@@ -528,6 +529,9 @@ struct rq {
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
u64 prev_irq_time;
#endif
+#ifdef CONFIG_PARAVIRT
+ u64 prev_steal_time;
+#endif
/* calc_load related fields */
unsigned long calc_load_update;
@@ -1953,6 +1957,18 @@ void account_system_vtime(struct task_struct *curr)
}
EXPORT_SYMBOL_GPL(account_system_vtime);
+#endif /* CONFIG_IRQ_TIME_ACCOUNTING */
+
+#ifdef CONFIG_PARAVIRT
+static inline u64 steal_ticks(u64 steal)
+{
+ if (unlikely(steal NSEC_PER_SEC))
+ return div_u64(steal, TICK_NSEC);
+
+ return __iter_div_u64_rem(steal, TICK_NSEC, steal);
+}
+#endif
+
static void update_rq_clock_task(struct rq *rq, s64 delta)
{
s64 irq_delta;
@@ -3845,6 +3861,25 @@ void account_idle_time(cputime_t cputime)
cpustat-idle = cputime64_add(cpustat-idle, cputime64);
}
+static __always_inline bool steal_account_process_tick(void)
+{
+#ifdef CONFIG_PARAVIRT
+ if (static_branch(paravirt_steal_enabled)) {
+ u64 steal, st = 0;
+
+ steal = paravirt_steal_clock(smp_processor_id());
+ steal -= this_rq()-prev_steal_time;
+
+ st = steal_ticks(steal);
+ this_rq()-prev_steal_time += st * TICK_NSEC;
+
+ account_steal_time(st);
+ return st;
+ }
+#endif
+ return false;
+}
+
#ifndef CONFIG_VIRT_CPU_ACCOUNTING
#ifdef CONFIG_IRQ_TIME_ACCOUNTING
@@ -3876,6 +3911,9 @@ static void irqtime_account_process_tick(struct
task_struct *p, int user_tick,
cputime64_t tmp = cputime_to_cputime64(cputime_one_jiffy);
struct cpu_usage_stat *cpustat = kstat_this_cpu.cpustat;
+ if (steal_account_process_tick())
+ return;
+
if (irqtime_account_hi_update()) {
cpustat-irq = cputime64_add(cpustat-irq, tmp);
} else if (irqtime_account_si_update()) {
@@ -3929,6 +3967,9 @@ void account_process_tick(struct task_struct *p, int
user_tick)
return;
}
+ if (steal_account_process_tick())
+ return;
+
if (user_tick)
account_user_time(p, cputime_one_jiffy, one_jiffy_scaled);
else if ((p != rq-idle) || (irq_count() != HARDIRQ_OFFSET))
--
1.7.3.4
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