4 files changed, 133 insertions, 0 deletions

diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c
index 3cffce90f82a..7bc64af7cf99 100644
--- a/drivers/oprofile/oprof.c
+++ b/drivers/oprofile/oprof.c
@@ -12,6 +12,8 @@
 #include <linux/init.h>
 #include <linux/oprofile.h>
 #include <linux/moduleparam.h>
+#include <linux/workqueue.h>
+#include <linux/time.h>
 #include <asm/mutex.h>
 
 #include "oprof.h"
@@ -27,6 +29,15 @@ unsigned long oprofile_backtrace_depth;
 static unsigned long is_setup;
 static DEFINE_MUTEX(start_mutex);
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+static void switch_worker(struct work_struct *work);
+static DECLARE_DELAYED_WORK(switch_work, switch_worker);
+unsigned long timeout_jiffies;
+#define MULTIPLEXING_TIMER_DEFAULT 1
+
+#endif
+
 /* timer
    0 - use performance monitoring hardware if available
    1 - use the timer int mechanism regardless
@@ -87,6 +98,20 @@ out:
         return err;
 }
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+static void start_switch_worker(void)
+{
+        schedule_delayed_work(&switch_work, timeout_jiffies);
+}
+
+static void switch_worker(struct work_struct *work)
+{
+        if (!oprofile_ops.switch_events())
+                start_switch_worker();
+}
+
+#endif
 
 /* Actually start profiling (echo 1>/dev/oprofile/enable) */
 int oprofile_start(void)
@@ -108,6 +133,11 @@ int oprofile_start(void)
         if ((err = oprofile_ops.start()))
                 goto out;
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        if (oprofile_ops.switch_events)
+                start_switch_worker();
+#endif
+
         oprofile_started = 1;
 out:
         mutex_unlock(&start_mutex);
@@ -123,6 +153,11 @@ void oprofile_stop(void)
                 goto out;
         oprofile_ops.stop();
         oprofile_started = 0;
+
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        cancel_delayed_work_sync(&switch_work);
+#endif
+
         /* wake up the daemon to read what remains */
         wake_up_buffer_waiter();
 out:
@@ -155,6 +190,36 @@ post_sync:
         mutex_unlock(&start_mutex);
 }
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+/* User inputs in ms, converts to jiffies */
+int oprofile_set_timeout(unsigned long val_msec)
+{
+        int err = 0;
+
+        mutex_lock(&start_mutex);
+
+        if (oprofile_started) {
+                err = -EBUSY;
+                goto out;
+        }
+
+        if (!oprofile_ops.switch_events) {
+                err = -EINVAL;
+                goto out;
+        }
+
+        timeout_jiffies = msecs_to_jiffies(val_msec);
+        if (timeout_jiffies == MAX_JIFFY_OFFSET)
+                timeout_jiffies = msecs_to_jiffies(MULTIPLEXING_TIMER_DEFAULT);
+
+out:
+        mutex_unlock(&start_mutex);
+        return err;
+
+}
+
+#endif
 
 int oprofile_set_backtrace(unsigned long val)
 {
@@ -179,10 +244,23 @@ out:
         return err;
 }
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+static void __init oprofile_multiplexing_init(void)
+{
+        timeout_jiffies = msecs_to_jiffies(MULTIPLEXING_TIMER_DEFAULT);
+}
+
+#endif
+
 static int __init oprofile_init(void)
 {
         int err;
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        oprofile_multiplexing_init();
+#endif
+
         err = oprofile_arch_init(&oprofile_ops);
 
         if (err < 0 || timer) {
diff --git a/drivers/oprofile/oprof.h b/drivers/oprofile/oprof.h
index c288d3c24b50..ee38abcc74f3 100644
--- a/drivers/oprofile/oprof.h
+++ b/drivers/oprofile/oprof.h
@@ -27,6 +27,7 @@ extern unsigned long oprofile_buffer_watershed;
 extern struct oprofile_operations oprofile_ops;
 extern unsigned long oprofile_started;
 extern unsigned long oprofile_backtrace_depth;
+extern unsigned long timeout_jiffies;
 
 struct super_block;
 struct dentry;
@@ -35,5 +36,6 @@ void oprofile_create_files(struct super_block *sb, struct dentry *root);
 void oprofile_timer_init(struct oprofile_operations *ops);
 
 int oprofile_set_backtrace(unsigned long depth);
+int oprofile_set_timeout(unsigned long time);
 
 #endif /* OPROF_H */
diff --git a/drivers/oprofile/oprofile_files.c b/drivers/oprofile/oprofile_files.c
index 5d36ffc30dd5..468ec3e4f856 100644
--- a/drivers/oprofile/oprofile_files.c
+++ b/drivers/oprofile/oprofile_files.c
@@ -9,6 +9,7 @@
 
 #include <linux/fs.h>
 #include <linux/oprofile.h>
+#include <linux/jiffies.h>
 
 #include "event_buffer.h"
 #include "oprofile_stats.h"
@@ -22,6 +23,45 @@ unsigned long oprofile_buffer_size;
 unsigned long oprofile_cpu_buffer_size;
 unsigned long oprofile_buffer_watershed;
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+static ssize_t timeout_read(struct file *file, char __user *buf,
+                size_t count, loff_t *offset)
+{
+        return oprofilefs_ulong_to_user(jiffies_to_msecs(timeout_jiffies),
+                                buf, count, offset);
+}
+
+
+static ssize_t timeout_write(struct file *file, char const __user *buf,
+                size_t count, loff_t *offset)
+{
+        unsigned long val;
+        int retval;
+
+        if (*offset)
+                return -EINVAL;
+
+        retval = oprofilefs_ulong_from_user(&val, buf, count);
+        if (retval)
+                return retval;
+
+        retval = oprofile_set_timeout(val);
+
+        if (retval)
+                return retval;
+        return count;
+}
+
+
+static const struct file_operations timeout_fops = {
+        .read           = timeout_read,
+        .write          = timeout_write,
+};
+
+#endif
+
+
 static ssize_t depth_read(struct file *file, char __user *buf, size_t count, loff_t *offset)
 {
         return oprofilefs_ulong_to_user(oprofile_backtrace_depth, buf, count,
@@ -139,6 +179,9 @@ void oprofile_create_files(struct super_block *sb, struct dentry *root)
         oprofilefs_create_file(sb, root, "cpu_type", &cpu_type_fops);
         oprofilefs_create_file(sb, root, "backtrace_depth", &depth_fops);
         oprofilefs_create_file(sb, root, "pointer_size", &pointer_size_fops);
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        oprofilefs_create_file(sb, root, "time_slice", &timeout_fops);
+#endif
         oprofile_create_stats_files(sb, root);
         if (oprofile_ops.create_files)
                 oprofile_ops.create_files(sb, root);
diff --git a/drivers/oprofile/oprofile_stats.c b/drivers/oprofile/oprofile_stats.c
index 3c2270a8300c..77a57a6792f6 100644
--- a/drivers/oprofile/oprofile_stats.c
+++ b/drivers/oprofile/oprofile_stats.c
@@ -16,6 +16,9 @@
 #include "cpu_buffer.h"
 
 struct oprofile_stat_struct oprofile_stats;
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+atomic_t multiplex_counter;
+#endif
 
 void oprofile_reset_stats(void)
 {
@@ -34,6 +37,9 @@ void oprofile_reset_stats(void)
         atomic_set(&oprofile_stats.sample_lost_no_mapping, 0);
         atomic_set(&oprofile_stats.event_lost_overflow, 0);
         atomic_set(&oprofile_stats.bt_lost_no_mapping, 0);
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        atomic_set(&multiplex_counter, 0);
+#endif
 }
 
 
@@ -76,4 +82,8 @@ void oprofile_create_stats_files(struct super_block *sb, struct dentry *root)
                 &oprofile_stats.event_lost_overflow);
         oprofilefs_create_ro_atomic(sb, dir, "bt_lost_no_mapping",
                 &oprofile_stats.bt_lost_no_mapping);
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        oprofilefs_create_ro_atomic(sb, dir, "multiplex_counter",
+                &multiplex_counter);
+#endif
 }