sched: latencytop support

LatencyTOP kernel infrastructure; it measures latencies in the
scheduler and tracks it system wide and per process.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

3 files changed, 52 insertions, 0 deletions

diff --git a/include/linux/latencytop.h b/include/linux/latencytop.h
new file mode 100644
index 00000000000..901c2d6377a
--- /dev/null
+++ b/include/linux/latencytop.h
@@ -0,0 +1,44 @@
+/*
+ * latencytop.h: Infrastructure for displaying latency
+ *
+ * (C) Copyright 2008 Intel Corporation
+ * Author: Arjan van de Ven <arjan@linux.intel.com>
+ *
+ */
+
+#ifndef _INCLUDE_GUARD_LATENCYTOP_H_
+#define _INCLUDE_GUARD_LATENCYTOP_H_
+
+#ifdef CONFIG_LATENCYTOP
+
+#define LT_SAVECOUNT            32
+#define LT_BACKTRACEDEPTH       12
+
+struct latency_record {
+        unsigned long   backtrace[LT_BACKTRACEDEPTH];
+        unsigned int    count;
+        unsigned long   time;
+        unsigned long   max;
+};
+
+
+struct task_struct;
+
+void account_scheduler_latency(struct task_struct *task, int usecs, int inter);
+
+void clear_all_latency_tracing(struct task_struct *p);
+
+#else
+
+static inline void
+account_scheduler_latency(struct task_struct *task, int usecs, int inter)
+{
+}
+
+static inline void clear_all_latency_tracing(struct task_struct *p)
+{
+}
+
+#endif
+
+#endif
diff --git a/include/linux/sched.h b/include/linux/sched.h
index acadcab89ef..dfc76e172f3 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -88,6 +88,7 @@ struct sched_param {
 #include <linux/hrtimer.h>
 #include <linux/task_io_accounting.h>
 #include <linux/kobject.h>
+#include <linux/latencytop.h>
 
 #include <asm/processor.h>
 
@@ -1220,6 +1221,10 @@ struct task_struct {
         int make_it_fail;
 #endif
         struct prop_local_single dirties;
+#ifdef CONFIG_LATENCYTOP
+        int latency_record_count;
+        struct latency_record latency_record[LT_SAVECOUNT];
+#endif
 };
 
 /*
diff --git a/include/linux/stacktrace.h b/include/linux/stacktrace.h
index e7fa657d0c4..5da9794b2d7 100644
--- a/include/linux/stacktrace.h
+++ b/include/linux/stacktrace.h
@@ -9,10 +9,13 @@ struct stack_trace {
 };
 
 extern void save_stack_trace(struct stack_trace *trace);
+extern void save_stack_trace_tsk(struct task_struct *tsk,
+                                struct stack_trace *trace);
 
 extern void print_stack_trace(struct stack_trace *trace, int spaces);
 #else
 # define save_stack_trace(trace)                        do { } while (0)
+# define save_stack_trace_tsk(tsk, trace)               do { } while (0)
 # define print_stack_trace(trace, spaces)               do { } while (0)
 #endif