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authorJason Baron2009-04-30 13:29:47 -0400
committerIngo Molnar2009-05-01 14:03:36 +0200
commit9ee1983c9aa18f12388ef660d0c76a23dc112959 (patch)
treed6ecce58d2a0ae99dd519f559f9c66383f9e6f90 /include/trace
parenta76f8c6da1e48fd4ef025f42c736389532ff30ba (diff)
tracing: add irq tracepoint documentation
Document irqs for the newly created docbook. [ Impact: add documentation ] Signed-off-by: Jason Baron <jbaron@redhat.com> Acked-by: Randy Dunlap <randy.dunlap@oracle.com> Cc: akpm@linux-foundation.org Cc: rostedt@goodmis.org Cc: fweisbec@gmail.com Cc: mathieu.desnoyers@polymtl.ca Cc: wcohen@redhat.com LKML-Reference: <73ff42be3420157667ec548e9b0e409c3cfad05f.1241107197.git.jbaron@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/trace')
-rw-r--r--include/trace/events/irq.h46
1 files changed, 42 insertions, 4 deletions
diff --git a/include/trace/events/irq.h b/include/trace/events/irq.h
index 768686467518..32a9f7ef432b 100644
--- a/include/trace/events/irq.h
+++ b/include/trace/events/irq.h
@@ -7,8 +7,16 @@
#undef TRACE_SYSTEM
#define TRACE_SYSTEM irq
-/*
- * Tracepoint for entry of interrupt handler:
+/**
+ * irq_handler_entry - called immediately before the irq action handler
+ * @irq: irq number
+ * @action: pointer to struct irqaction
+ *
+ * The struct irqaction pointed to by @action contains various
+ * information about the handler, including the device name,
+ * @action->name, and the device id, @action->dev_id. When used in
+ * conjunction with the irq_handler_exit tracepoint, we can figure
+ * out irq handler latencies.
*/
TRACE_EVENT(irq_handler_entry,
@@ -29,8 +37,16 @@ TRACE_EVENT(irq_handler_entry,
TP_printk("irq=%d handler=%s", __entry->irq, __get_str(name))
);
-/*
- * Tracepoint for return of an interrupt handler:
+/**
+ * irq_handler_exit - called immediately after the irq action handler returns
+ * @irq: irq number
+ * @action: pointer to struct irqaction
+ * @ret: return value
+ *
+ * If the @ret value is set to IRQ_HANDLED, then we know that the corresponding
+ * @action->handler scuccessully handled this irq. Otherwise, the irq might be
+ * a shared irq line, or the irq was not handled successfully. Can be used in
+ * conjunction with the irq_handler_entry to understand irq handler latencies.
*/
TRACE_EVENT(irq_handler_exit,
@@ -52,6 +68,17 @@ TRACE_EVENT(irq_handler_exit,
__entry->irq, __entry->ret ? "handled" : "unhandled")
);
+/**
+ * softirq_entry - called immediately before the softirq handler
+ * @h: pointer to struct softirq_action
+ * @vec: pointer to first struct softirq_action in softirq_vec array
+ *
+ * The @h parameter, contains a pointer to the struct softirq_action
+ * which has a pointer to the action handler that is called. By subtracting
+ * the @vec pointer from the @h pointer, we can determine the softirq
+ * number. Also, when used in combination with the softirq_exit tracepoint
+ * we can determine the softirq latency.
+ */
TRACE_EVENT(softirq_entry,
TP_PROTO(struct softirq_action *h, struct softirq_action *vec),
@@ -71,6 +98,17 @@ TRACE_EVENT(softirq_entry,
TP_printk("softirq=%d action=%s", __entry->vec, __get_str(name))
);
+/**
+ * softirq_exit - called immediately after the softirq handler returns
+ * @h: pointer to struct softirq_action
+ * @vec: pointer to first struct softirq_action in softirq_vec array
+ *
+ * The @h parameter contains a pointer to the struct softirq_action
+ * that has handled the softirq. By subtracting the @vec pointer from
+ * the @h pointer, we can determine the softirq number. Also, when used in
+ * combination with the softirq_entry tracepoint we can determine the softirq
+ * latency.
+ */
TRACE_EVENT(softirq_exit,
TP_PROTO(struct softirq_action *h, struct softirq_action *vec),