cpuidle: haltpoll: Add trace points for guest_halt_poll_ns grow/shrink

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>
Acked-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpuidle/governors/haltpoll.c b/drivers/cpuidle/governors/haltpoll.c
index cb2a96eafc02750acc5e7e66fa53cea18a50523a..1dff3a52917de9a6b79d1cd9e301a24659b412f6 100644 (file)
--- 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);
@@ -90,6 +91,7 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
                if (val > guest_halt_poll_ns)
                        val = guest_halt_poll_ns;
 
+               trace_guest_halt_poll_ns_grow(val, dev->poll_limit_ns);
                dev->poll_limit_ns = val;
        } else if (block_ns > guest_halt_poll_ns &&
                   guest_halt_poll_allow_shrink) {
@@ -100,6 +102,7 @@ static void adjust_poll_limit(struct cpuidle_device *dev, u64 block_ns)
                        val = 0;
                else
                        val /= shrink;
+               trace_guest_halt_poll_ns_shrink(val, dev->poll_limit_ns);
                dev->poll_limit_ns = val;
        }
 }

diff --git a/include/trace/events/power.h b/include/trace/events/power.h
index af5018aa951775337fcd5be1b883def0bf52c62a..c708521e4ed5d683f624da5071d3ff9b83c8e90c 100644 (file)
--- a/include/trace/events/power.h
+++ b/include/trace/events/power.h
@@ -500,6 +500,35 @@ 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 new, unsigned int old),
+
+       TP_ARGS(grow, new, old),
+
+       TP_STRUCT__entry(
+               __field(bool, grow)
+               __field(unsigned int, new)
+               __field(unsigned int, old)
+       ),
+
+       TP_fast_assign(
+               __entry->grow   = grow;
+               __entry->new    = new;
+               __entry->old    = old;
+       ),
+
+       TP_printk("halt_poll_ns %u (%s %u)",
+               __entry->new,
+               __entry->grow ? "grow" : "shrink",
+               __entry->old)
+);
+
+#define trace_guest_halt_poll_ns_grow(new, old) \
+       trace_guest_halt_poll_ns(true, new, old)
+#define trace_guest_halt_poll_ns_shrink(new, old) \
+       trace_guest_halt_poll_ns(false, new, old)
 #endif /* _TRACE_POWER_H */
 
 /* This part must be outside protection */