Add trace points as are implemented in KVM host halt polling.
This helps tune guest halt polling params.
Signed-off-by: Eiichi Tsukata <[email protected]>
---
drivers/cpuidle/governors/haltpoll.c | 15 ++++++++-----
include/trace/events/power.h | 33 ++++++++++++++++++++++++++++
2 files changed, 43 insertions(+), 5 deletions(-)
diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
index cb2a96eafc02..a5b6ad32956c 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 +78,16 @@ 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
+ val = dev->poll_limit_ns;
+ old = val;
+
+ /* Grow poll_limit_ns if
+ * poll_limit_ns < block_ns < guest_halt_poll_ns
*/
if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {
- val = dev->poll_limit_ns * guest_halt_poll_grow;
+ val *= guest_halt_poll_grow;
if (val < guest_halt_poll_grow_start)
val = guest_halt_poll_grow_start;
@@ -91,16 +95,17 @@ 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;
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
Hi Steven
> On May 26, 2022, at 1:02, Steven Rostedt <[email protected]> wrote:
>
> On Mon, 23 May 2022 23:53:32 +0000
> Eiichi Tsukata <[email protected]> wrote:
>
>> @@ -91,16 +95,17 @@ 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);
>
> Why are you passing in smp_processor_id()?
>
>> } 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;
>> 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;
>
> You are wasting space to save the cpu_id, as the trace event already knows
> what CPU it occurred on.
>
> # echo 1 > events/sched/enable
> # cat trace
> # TASK-PID CPU# ||||| TIMESTAMP FUNCTION
> # | | | ||||| | |
> systemd-1 [004] ..... 15.872715: ftrace_boot_snapshot: ** Boot snapshot taken **
> systemd-1 [001] ..... 22.555418: initcall_start: func=fuse_len_args+0x0/0x30 [fuse]
> systemd-1 [001] ..... 22.555425: initcall_finish: func=fuse_len_args+0x0/0x30 [fuse] ret=0
> modprobe-643 [006] ..... 26.737355: initcall_start: func=wmidev_evaluate_method+0x46/0x100 [wmi]
> modprobe-643 [006] ..... 26.742491: initcall_finish: func=wmidev_evaluate_method+0x46/0x100 [wmi] ret=0
>
> -- Steve
Thanks for your suggestion.
I added cpu_id as there is a similar precedent “trace_cpu_idle” but I think we can remove cpu_id.
Will fix it in v3.
Eiichi
On Mon, 23 May 2022 23:53:32 +0000
Eiichi Tsukata <[email protected]> wrote:
> @@ -91,16 +95,17 @@ 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);
Why are you passing in smp_processor_id()?
> } 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;
> 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;
You are wasting space to save the cpu_id, as the trace event already knows
what CPU it occurred on.
# echo 1 > events/sched/enable
# cat trace
# TASK-PID CPU# ||||| TIMESTAMP FUNCTION
# | | | ||||| | |
systemd-1 [004] ..... 15.872715: ftrace_boot_snapshot: ** Boot snapshot taken **
systemd-1 [001] ..... 22.555418: initcall_start: func=fuse_len_args+0x0/0x30 [fuse]
systemd-1 [001] ..... 22.555425: initcall_finish: func=fuse_len_args+0x0/0x30 [fuse] ret=0
modprobe-643 [006] ..... 26.737355: initcall_start: func=wmidev_evaluate_method+0x46/0x100 [wmi]
modprobe-643 [006] ..... 26.742491: initcall_finish: func=wmidev_evaluate_method+0x46/0x100 [wmi] ret=0
-- Steve
> + __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)
> +);
> +
On Mon, May 23, 2022 at 11:53:32PM +0000, Eiichi Tsukata wrote:
> Add trace points as are implemented in KVM host halt polling.
> This helps tune guest halt polling params.
>
> Signed-off-by: Eiichi Tsukata <[email protected]>
> ---
> drivers/cpuidle/governors/haltpoll.c | 15 ++++++++-----
> include/trace/events/power.h | 33 ++++++++++++++++++++++++++++
> 2 files changed, 43 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
> index cb2a96eafc02..a5b6ad32956c 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 +78,16 @@ 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
> + val = dev->poll_limit_ns;
> + old = val;
> +
> + /* Grow poll_limit_ns if
> + * poll_limit_ns < block_ns < guest_halt_poll_ns
> */
> if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {
> - val = dev->poll_limit_ns * guest_halt_poll_grow;
> + val *= guest_halt_poll_grow;
>
> if (val < guest_halt_poll_grow_start)
> val = guest_halt_poll_grow_start;
> @@ -91,16 +95,17 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
> val = guest_halt_poll_ns;
>
Can do it before the assignment:
trace_guest_halt_poll_ns_grow(val, dev->poll_limit_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;
> 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
>
>
Hi Marcelo
> On May 26, 2022, at 2:31, Marcelo Tosatti <[email protected]> wrote:
>
> On Mon, May 23, 2022 at 11:53:32PM +0000, Eiichi Tsukata wrote:
>> Add trace points as are implemented in KVM host halt polling.
>> This helps tune guest halt polling params.
>>
>> Signed-off-by: Eiichi Tsukata <[email protected]>
>> ---
>> drivers/cpuidle/governors/haltpoll.c | 15 ++++++++-----
>> include/trace/events/power.h | 33 ++++++++++++++++++++++++++++
>> 2 files changed, 43 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
>> index cb2a96eafc02..a5b6ad32956c 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 +78,16 @@ 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
>> + val = dev->poll_limit_ns;
>> + old = val;
>> +
>> + /* Grow poll_limit_ns if
>> + * poll_limit_ns < block_ns < guest_halt_poll_ns
>> */
>> if (block_ns > dev->poll_limit_ns && block_ns <= guest_halt_poll_ns) {
>> - val = dev->poll_limit_ns * guest_halt_poll_grow;
>> + val *= guest_halt_poll_grow;
>>
>> if (val < guest_halt_poll_grow_start)
>> val = guest_halt_poll_grow_start;
>> @@ -91,16 +95,17 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
>> val = guest_halt_poll_ns;
>>
>
> Can do it before the assignment:
>
> trace_guest_halt_poll_ns_grow(val, dev->poll_limit_ns);
Sure. Will fix it in v4.
Thanks
Eiichi