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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 12/15] xen: trace tasklets
Making it possible generate events showing the
activity and the behavior of tasklets.
Gate this with its specific Kconfig option (under
CONFIG_TRACING), and keep it in disabled state by
default.
---
Cc: George Dunlap <George.Dunlap@xxxxxxxxxxxxx>
Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
Cc: Jan Beulich <jbeulich@xxxxxxxx>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx>
Cc: Tim Deegan <tim@xxxxxxx>
---
xen/Kconfig.debug | 8 ++++
xen/common/tasklet.c | 87 ++++++++++++++++++++++++++++++++++++++++++++
xen/include/public/trace.h | 9 +++++
3 files changed, 104 insertions(+)
diff --git a/xen/Kconfig.debug b/xen/Kconfig.debug
index 4979e83..f7b2e06 100644
--- a/xen/Kconfig.debug
+++ b/xen/Kconfig.debug
@@ -132,6 +132,14 @@ config TRACE_SOFTIRQS
Makes it possible to generate events related to raising and
handling of softirqs within Xen.
+config TRACE_TASKLETS
+ bool "Trace when tasklets are queued and scheduled" if EXPERT = "y"
+ default n
+ depends on TRACING
+ ---help---
+ Make it possible to generate events related to scheduling,
+ queueing and running of tasklets within Xen.
+
config VERBOSE_DEBUG
bool "Verbose debug messages"
default DEBUG
diff --git a/xen/common/tasklet.c b/xen/common/tasklet.c
index 365a777..20b9d68 100644
--- a/xen/common/tasklet.c
+++ b/xen/common/tasklet.c
@@ -30,10 +30,87 @@ static DEFINE_PER_CPU(struct list_head,
softirq_tasklet_list);
/* Protects all lists and tasklet structures. */
static DEFINE_SPINLOCK(tasklet_lock);
+#ifdef CONFIG_TRACE_TASKLETS
+static inline void trace_enqueue(const struct tasklet *t)
+{
+ uint64_t addr;
+
+ if ( likely(!tb_init_done) )
+ return;
+
+ addr = (uint64_t)t->func;
+ __trace_var(TRC_XEN_TASKLET_ENQUEUE, 0, sizeof(addr), &addr);
+}
+static inline void trace_schedule(const struct tasklet *t)
+{
+ struct {
+ uint64_t addr;
+ int16_t sched_on, is_sirq;
+ } d;
+
+ if ( likely(!tb_init_done) )
+ return;
+
+ d.addr = (uint64_t)t->func;
+ d.sched_on = t->scheduled_on;
+ d.is_sirq = t->is_softirq;
+ __trace_var(TRC_XEN_TASKLET_SCHEDULE, 1, sizeof(d), &d);
+}
+static inline void trace_work(const struct tasklet *t)
+{
+ uint64_t addr;
+
+ if ( likely(!tb_init_done) )
+ return;
+
+ addr = (uint64_t)t->func;
+ __trace_var(TRC_XEN_TASKLET_WORK, 1, sizeof(addr), &addr);
+}
+static inline void trace_kill(const struct tasklet *t)
+{
+ struct {
+ uint64_t addr;
+ int16_t sched_on, is_run;
+ } d;
+
+ if ( likely(!tb_init_done) )
+ return;
+
+ d.addr = (uint64_t)t->func;
+ d.sched_on = t->scheduled_on;
+ d.is_run = t->is_running;
+ __trace_var(TRC_XEN_TASKLET_KILL, 0, sizeof(d), &d);
+}
+static inline void trace_init(const struct tasklet *t)
+{
+ struct {
+ uint64_t addr;
+ uint32_t is_sirq;
+ } d;
+
+ if ( likely(!tb_init_done) )
+ return;
+
+ d.addr = (uint64_t)t->func;
+ d.is_sirq = t->is_softirq;
+ __trace_var(TRC_XEN_TASKLET_INIT, 0, sizeof(d), &d);
+}
+#define trace_migrate() TRACE_0D(TRC_XEN_TASKLET_MIGR);
+#else
+#define trace_enqueue(t) do {} while ( 0 )
+#define trace_schedule(t) do {} while ( 0 )
+#define trace_work(t) do {} while ( 0 )
+#define trace_kill(t) do {} while ( 0 )
+#define trace_migrate() do {} while ( 0 )
+#define trace_init(t) do {} while ( 0 )
+#endif /* TRACE_TASKLETS */
+
static void tasklet_enqueue(struct tasklet *t)
{
unsigned int cpu = t->scheduled_on;
+ trace_enqueue(t);
+
if ( t->is_softirq )
{
struct list_head *list = &per_cpu(softirq_tasklet_list, cpu);
@@ -60,6 +137,7 @@ void tasklet_schedule_on_cpu(struct tasklet *t, unsigned int
cpu)
if ( tasklets_initialised && !t->is_dead )
{
t->scheduled_on = cpu;
+ trace_schedule(t);
if ( !t->is_running )
{
list_del(&t->list);
@@ -91,6 +169,7 @@ static void do_tasklet_work(unsigned int cpu, struct
list_head *list)
spin_unlock_irq(&tasklet_lock);
sync_local_execstate();
+ trace_work(t);
t->func(t->data);
spin_lock_irq(&tasklet_lock);
@@ -158,6 +237,7 @@ void tasklet_kill(struct tasklet *t)
list_del_init(&t->list);
}
+ trace_kill(t);
t->scheduled_on = -1;
t->is_dead = 1;
@@ -178,6 +258,11 @@ static void migrate_tasklets_from_cpu(unsigned int cpu,
struct list_head *list)
spin_lock_irqsave(&tasklet_lock, flags);
+ if ( list_empty(list) )
+ goto out;
+
+ trace_migrate();
+
while ( !list_empty(list) )
{
t = list_entry(list->next, struct tasklet, list);
@@ -187,6 +272,7 @@ static void migrate_tasklets_from_cpu(unsigned int cpu,
struct list_head *list)
tasklet_enqueue(t);
}
+ out:
spin_unlock_irqrestore(&tasklet_lock, flags);
}
@@ -198,6 +284,7 @@ void tasklet_init(
t->scheduled_on = -1;
t->func = func;
t->data = data;
+ trace_init(t);
}
void softirq_tasklet_init(
diff --git a/xen/include/public/trace.h b/xen/include/public/trace.h
index 9d065aa..acee7d5 100644
--- a/xen/include/public/trace.h
+++ b/xen/include/public/trace.h
@@ -96,6 +96,7 @@
/* Trace subclasses for Xen internals */
#define TRC_XEN_RCU 0x01001000 /* RCU traces */
#define TRC_XEN_SIRQ 0x01002000 /* Traces relating to softirqs */
+#define TRC_XEN_TSKLT 0x01004000 /* Traces relating to tasklets */
/* Trace events per class */
#define TRC_LOST_RECORDS (TRC_GEN + 1)
@@ -299,6 +300,14 @@
#define TRC_XEN_SIRQ_RAISE_CPU (TRC_XEN_SIRQ + 0x3)
#define TRC_XEN_SIRQ_RAISE (TRC_XEN_SIRQ + 0x4)
+/* Trace events for tasklets */
+#define TRC_XEN_TASKLET_ENQUEUE (TRC_XEN_TSKLT + 0x1)
+#define TRC_XEN_TASKLET_SCHEDULE (TRC_XEN_TSKLT + 0x2)
+#define TRC_XEN_TASKLET_WORK (TRC_XEN_TSKLT + 0x3)
+#define TRC_XEN_TASKLET_KILL (TRC_XEN_TSKLT + 0x4)
+#define TRC_XEN_TASKLET_INIT (TRC_XEN_TSKLT + 0x5)
+#define TRC_XEN_TASKLET_MIGR (TRC_XEN_TSKLT + 0x6)
+
/*
* Event Flags
*
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