* [PATCH] cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink
@ 2022-05-23 6:35 Eiichi Tsukata
2022-05-23 11:33 ` Eiichi Tsukata
0 siblings, 1 reply; 2+ messages in thread
From: Eiichi Tsukata @ 2022-05-23 6:35 UTC (permalink / raw)
To: rafael, daniel.lezcano, rostedt, mingo, linux-pm, linux-kernel,
joao.m.martins, mtosatti
Cc: Eiichi Tsukata
Add trace points as are implemented in KVM host halt polling.
This helps tune guest halt polling params.
Signed-off-by: Eiichi Tsukata <eiichi.tsukata@nutanix.com>
---
drivers/cpuidle/governors/haltpoll.c | 7 +++++-
include/trace/events/power.h | 33 ++++++++++++++++++++++++++++
2 files changed, 39 insertions(+), 1 deletion(-)
diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
index cb2a96eafc02..9a6eca41a484 100644
--- a/drivers/cpuidle/governors/haltpoll.c
+++ b/drivers/cpuidle/governors/haltpoll.c
@@ -19,6 +19,7 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/kvm_para.h>
+#include <trace/events/power.h>
static unsigned int guest_halt_poll_ns __read_mostly = 200000;
module_param(guest_halt_poll_ns, uint, 0644);
@@ -77,13 +78,14 @@ static int haltpoll_select(struct cpuidle_driver *drv,
static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
{
- unsigned int val;
+ unsigned int val, old;
/* Grow cpu_halt_poll_us if
* cpu_halt_poll_us < block_ns < guest_halt_poll_us
*/
if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {
val = dev->poll_limit_ns * guest_halt_poll_grow;
+ old = val;
if (val < guest_halt_poll_grow_start)
val = guest_halt_poll_grow_start;
@@ -91,16 +93,19 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
val = guest_halt_poll_ns;
dev->poll_limit_ns = val;
+ trace_guest_halt_poll_ns_grow(smp_processor_id(), val, old);
} else if (block_ns > guest_halt_poll_ns &&
guest_halt_poll_allow_shrink) {
unsigned int shrink = guest_halt_poll_shrink;
val = dev->poll_limit_ns;
+ old = val;
if (shrink == 0)
val = 0;
else
val /= shrink;
dev->poll_limit_ns = val;
+ trace_guest_halt_poll_ns_shrink(smp_processor_id(), val, old);
}
}
diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index af5018aa9517..db065af9c3c0 100644
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -500,6 +500,39 @@ DEFINE_EVENT(dev_pm_qos_request, dev_pm_qos_remove_request,
TP_ARGS(name, type, new_value)
);
+
+TRACE_EVENT(guest_halt_poll_ns,
+
+ TP_PROTO(bool grow, unsigned int cpu_id,
+ unsigned int new, unsigned int old),
+
+ TP_ARGS(grow, cpu_id, new, old),
+
+ TP_STRUCT__entry(
+ __field(bool, grow)
+ __field(unsigned int, cpu_id)
+ __field(unsigned int, new)
+ __field(unsigned int, old)
+ ),
+
+ TP_fast_assign(
+ __entry->grow = grow;
+ __entry->cpu_id = cpu_id;
+ __entry->new = new;
+ __entry->old = old;
+ ),
+
+ TP_printk("cpu %u: halt_poll_ns %u (%s %u)",
+ __entry->cpu_id,
+ __entry->new,
+ __entry->grow ? "grow" : "shrink",
+ __entry->old)
+);
+
+#define trace_guest_halt_poll_ns_grow(cpu_id, new, old) \
+ trace_guest_halt_poll_ns(true, cpu_id, new, old)
+#define trace_guest_halt_poll_ns_shrink(cpu_id, new, old) \
+ trace_guest_halt_poll_ns(false, cpu_id, new, old)
#endif /* _TRACE_POWER_H */
/* This part must be outside protection */
--
2.36.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink
2022-05-23 6:35 [PATCH] cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink Eiichi Tsukata
@ 2022-05-23 11:33 ` Eiichi Tsukata
0 siblings, 0 replies; 2+ messages in thread
From: Eiichi Tsukata @ 2022-05-23 11:33 UTC (permalink / raw)
To: rafael, daniel.lezcano, rostedt, mingo, linux-pm, linux-kernel,
joao.m.martins, mtosatti
> On May 23, 2022, at 15:35, Eiichi Tsukata <eiichi.tsukata@nutanix.com> wrote:
>
> Add trace points as are implemented in KVM host halt polling.
> This helps tune guest halt polling params.
>
> Signed-off-by: Eiichi Tsukata <eiichi.tsukata@nutanix.com>
> ---
> drivers/cpuidle/governors/haltpoll.c | 7 +++++-
> include/trace/events/power.h | 33 ++++++++++++++++++++++++++++
> 2 files changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
> index cb2a96eafc02..9a6eca41a484 100644
> --- a/drivers/cpuidle/governors/haltpoll.c
> +++ b/drivers/cpuidle/governors/haltpoll.c
> @@ -19,6 +19,7 @@
> #include <linux/sched.h>
> #include <linux/module.h>
> #include <linux/kvm_para.h>
> +#include <trace/events/power.h>
>
> static unsigned int guest_halt_poll_ns __read_mostly = 200000;
> module_param(guest_halt_poll_ns, uint, 0644);
> @@ -77,13 +78,14 @@ static int haltpoll_select(struct cpuidle_driver *drv,
>
> static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
> {
> - unsigned int val;
> + unsigned int val, old;
>
> /* Grow cpu_halt_poll_us if
> * cpu_halt_poll_us < block_ns < guest_halt_poll_us
> */
> if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {
> val = dev->poll_limit_ns * guest_halt_poll_grow;
> + old = val;
This sets wrong old val. Will fix it in v2.
Eiichi
^ permalink raw reply [flat|nested] 2+ messages in thread
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2022-05-23 6:35 [PATCH] cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink Eiichi Tsukata
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