6 files changed, 122 insertions, 0 deletions
diff --git a/testsuite/systemtap.examples/index.html b/testsuite/systemtap.examples/index.html
index ba0d0fd7..66118bfc 100644
--- a/testsuite/systemtap.examples/index.html
+++ b/testsuite/systemtap.examples/index.html
@@ -196,6 +196,9 @@ keywords: <a href="keyword-index.html#SYSCALL">SYSCALL</a> <a href="keyword-inde
 <li><a href="profiling/functioncallcount.stp">profiling/functioncallcount.stp</a> - Count Times Functions Called<br>
 keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <a href="keyword-index.html#FUNCTIONS">FUNCTIONS</a> <br>
 <p>The functioncallcount.stp script takes one argument, a list of functions to probe. The script will run and count the number of times that each of the functions on the list is called. On exit the script will print a sorted list from most frequently to least frequently called function.</p></li>
+<li><a href="profiling/sched_switch.stp">profiling/sched_switch.stp</a> - Display the task switches happening in the scheduler<br>
+keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <a href="keyword-index.html#FUNCTIONS">FUNCTIONS</a> <br>
+<p>The sched_switch.stp script takes two arguments, first argument can be "pid" or "name" to indicate what is being passed as second argument. The script will trace the process based on pid/name and print the scheduler switches happening with the process. If no arguments are passed, it displays all the scheduler switches. This can be used to understand which tasks schedule out the current process being traced, and when it gets scheduled in again.</p></li>
 <li><a href="profiling/thread-times.stp">profiling/thread-times.stp</a> - Profile kernel functions<br>
 keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <br>
 <p>The thread-times.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty processes with samples broken down into percentage total time spent in user-space and kernel-space.</p></li>
diff --git a/testsuite/systemtap.examples/index.txt b/testsuite/systemtap.examples/index.txt
index 3d0495f5..cb2b10d3 100644
--- a/testsuite/systemtap.examples/index.txt
+++ b/testsuite/systemtap.examples/index.txt
@@ -488,6 +488,18 @@ keywords: profiling functions
   called function.
 
 
+profiling/sched_switch.stp - Display the task switches happening in the scheduler
+keywords: profiling functions
+
+  The sched_switch.stp script takes two arguments, first argument can
+  be "pid" or "name" to indicate what is being passed as second
+  argument. The script will trace the process based on pid/name and
+  print the scheduler switches happening with the process. If no
+  arguments are passed, it displays all the scheduler switches. This
+  can be used to understand which tasks schedule out the current
+  process being traced, and when it gets scheduled in again.
+
+
 profiling/thread-times.stp - Profile kernel functions
 keywords: profiling
 
diff --git a/testsuite/systemtap.examples/keyword-index.html b/testsuite/systemtap.examples/keyword-index.html
index 1a68a9f0..2aad9adf 100644
--- a/testsuite/systemtap.examples/keyword-index.html
+++ b/testsuite/systemtap.examples/keyword-index.html
@@ -120,6 +120,9 @@ keywords: <a href="keyword-index.html#NETWORK">NETWORK</a> <a href="keyword-inde
 <li><a href="profiling/functioncallcount.stp">profiling/functioncallcount.stp</a> - Count Times Functions Called<br>
 keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <a href="keyword-index.html#FUNCTIONS">FUNCTIONS</a> <br>
 <p>The functioncallcount.stp script takes one argument, a list of functions to probe. The script will run and count the number of times that each of the functions on the list is called. On exit the script will print a sorted list from most frequently to least frequently called function.</p></li>
+<li><a href="profiling/sched_switch.stp">profiling/sched_switch.stp</a> - Display the task switches happening in the scheduler<br>
+keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <a href="keyword-index.html#FUNCTIONS">FUNCTIONS</a> <br>
+<p>The sched_switch.stp script takes two arguments, first argument can be "pid" or "name" to indicate what is being passed as second argument. The script will trace the process based on pid/name and print the scheduler switches happening with the process. If no arguments are passed, it displays all the scheduler switches. This can be used to understand which tasks schedule out the current process being traced, and when it gets scheduled in again.</p></li>
 </ul>
 <h3><a name="FUTEX">FUTEX</a></h3>
 <ul>
@@ -300,6 +303,9 @@ keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <br>
 <li><a href="profiling/functioncallcount.stp">profiling/functioncallcount.stp</a> - Count Times Functions Called<br>
 keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <a href="keyword-index.html#FUNCTIONS">FUNCTIONS</a> <br>
 <p>The functioncallcount.stp script takes one argument, a list of functions to probe. The script will run and count the number of times that each of the functions on the list is called. On exit the script will print a sorted list from most frequently to least frequently called function.</p></li>
+<li><a href="profiling/sched_switch.stp">profiling/sched_switch.stp</a> - Display the task switches happening in the scheduler<br>
+keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <a href="keyword-index.html#FUNCTIONS">FUNCTIONS</a> <br>
+<p>The sched_switch.stp script takes two arguments, first argument can be "pid" or "name" to indicate what is being passed as second argument. The script will trace the process based on pid/name and print the scheduler switches happening with the process. If no arguments are passed, it displays all the scheduler switches. This can be used to understand which tasks schedule out the current process being traced, and when it gets scheduled in again.</p></li>
 <li><a href="profiling/thread-times.stp">profiling/thread-times.stp</a> - Profile kernel functions<br>
 keywords: <a href="keyword-index.html#PROFILING">PROFILING</a> <br>
 <p>The thread-times.stp script sets up time-based sampling. Every five seconds it prints out a sorted list with the top twenty processes with samples broken down into percentage total time spent in user-space and kernel-space.</p></li>
diff --git a/testsuite/systemtap.examples/keyword-index.txt b/testsuite/systemtap.examples/keyword-index.txt
index 056b553a..01661cf1 100644
--- a/testsuite/systemtap.examples/keyword-index.txt
+++ b/testsuite/systemtap.examples/keyword-index.txt
@@ -154,6 +154,18 @@ keywords: profiling functions
   called function.
 
 
+profiling/sched_switch.stp - Display the task switches happening in the scheduler
+keywords: profiling functions
+
+  The sched_switch.stp script takes two arguments, first argument can
+  be "pid" or "name" to indicate what is being passed as second
+  argument. The script will trace the process based on pid/name and
+  print the scheduler switches happening with the process. If no
+  arguments are passed, it displays all the scheduler switches. This
+  can be used to understand which tasks schedule out the current
+  process being traced, and when it gets scheduled in again.
+
+
 = FUTEX =
 
 process/futexes.stp - System-Wide Futex Contention
@@ -618,6 +630,18 @@ keywords: profiling functions
   called function.
 
 
+profiling/sched_switch.stp - Display the task switches happening in the scheduler
+keywords: profiling functions
+
+  The sched_switch.stp script takes two arguments, first argument can
+  be "pid" or "name" to indicate what is being passed as second
+  argument. The script will trace the process based on pid/name and
+  print the scheduler switches happening with the process. If no
+  arguments are passed, it displays all the scheduler switches. This
+  can be used to understand which tasks schedule out the current
+  process being traced, and when it gets scheduled in again.
+
+
 profiling/thread-times.stp - Profile kernel functions
 keywords: profiling
 
diff --git a/testsuite/systemtap.examples/profiling/sched_switch.meta b/testsuite/systemtap.examples/profiling/sched_switch.meta
new file mode 100644
index 00000000..b202a74c
--- /dev/null
+++ b/testsuite/systemtap.examples/profiling/sched_switch.meta
@@ -0,0 +1,14 @@
+title: Display the task switches happening in the scheduler
+name: sched_switch.stp
+version: 1.0
+author: kiran
+keywords: profiling functions
+subsystem: kernel
+status: production
+exit: user-controlled
+output: trace
+scope: system-wide
+description: The sched_switch.stp script takes two arguments, first argument can be "pid" or "name" to indicate what is being passed as second argument. The script will trace the process based on pid/name and print the scheduler switches happening with the process. If no arguments are passed, it displays all the scheduler switches. This can be used to understand which tasks schedule out the current process being traced, and when it gets scheduled in again.
+test_check: stap -p4 sched_switch.stp
+test_installcheck: stap  sched_switch.stp -c "sleep 1"
+
diff --git a/testsuite/systemtap.examples/profiling/sched_switch.stp b/testsuite/systemtap.examples/profiling/sched_switch.stp
new file mode 100755
index 00000000..1c1b18b7
--- /dev/null
+++ b/testsuite/systemtap.examples/profiling/sched_switch.stp
@@ -0,0 +1,63 @@
+#! /usr/bin/env stap
+/* This script works similar to ftrace's sched_switch. It displays a list of
+ * processes which get switched in and out of the scheduler. The format of display
+ * is PROCESS_NAME PROCESS_PID CPU TIMESTAMP PID: PRIORITY: PROCESS STATE ->/+
+ *    NEXT_PID : NEXT_PRIORITY: NEXT_STATE NEXT_PROCESS_NAME 
+ * -> indicates that prev process is scheduled out and the next process is 
+ *    scheduled in.
+ * + indicates that prev process has woken up the next process.
+ * The usage is sched_switch.stp <"pid"/"name"> pid/name
+ */
+
+function state_calc(state) {
+	if(state == 0)
+	status = "R"
+	if(state == 1)
+	status = "S"
+	if(state == 2)
+	status = "D"
+	if(state == 4)
+	status = "T"
+	if(state == 8)
+	status = "T"
+	if(state == 16)
+	status = "Z"
+	if(state == 32)
+	status = "EXIT_DEAD"
+	return status
+}
+probe scheduler.wakeup
+{
+	 %( $# == 2 %?
+
+	if(@1 == "pid")
+		if (task_pid != $2 && pid() != $2)
+			next
+	if(@1 == "name")
+		if (task_execname(task) != @2 && execname() != @2)
+			next
+
+         %)
+
+	printf("%-16s%5d%5d%d:%d:%s + %d:%d:%s %16s\n",
+                execname(), task_cpu(task), gettimeofday_ns(),
+                pid(), task_prio(task_current()), state_calc(task_state(task_current())),
+                task_pid(task), task_prio(task), state_calc(task_state(task)),
+                task_execname(task))
+}
+probe scheduler.ctxswitch
+{
+	%( $# == 2 %?
+	
+	if(@1 == "pid") 
+		if (next_pid != $2 && prev_pid != $2)
+			next
+	if(@1 == "name")
+		if (prev_task_name != @2 && next_task_name != @2)
+			next 
+	%)
+
+	printf("%-16s%5d%5d%d:%d:%s ==> %d:%d:%s %16s\n",prev_task_name,
+		task_cpu(prev_task),gettimeofday_ns(),prev_pid,prev_priority,state_calc(prevtsk_state),next_pid,
+		next_priority,state_calc(nexttsk_state),next_task_name)
+}