oprofile: Implement performance counter multiplexing
[linux-2.6.git] / drivers / oprofile / oprof.c
index 2c64517..7bc64af 100644 (file)
@@ -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"
 #include "cpu_buffer.h"
 #include "buffer_sync.h"
 #include "oprofile_stats.h"
+
 struct oprofile_operations oprofile_ops;
 
 unsigned long oprofile_started;
-unsigned long backtrace_depth;
+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
@@ -36,7 +47,7 @@ static int timer = 0;
 int oprofile_setup(void)
 {
        int err;
+
        mutex_lock(&start_mutex);
 
        if ((err = alloc_cpu_buffers()))
@@ -44,10 +55,10 @@ int oprofile_setup(void)
 
        if ((err = alloc_event_buffer()))
                goto out1;
+
        if (oprofile_ops.setup && (err = oprofile_ops.setup()))
                goto out2;
+
        /* Note even though this starts part of the
         * profiling overhead, it's necessary to prevent
         * us missing task deaths and eventually oopsing
@@ -74,7 +85,7 @@ post_sync:
        is_setup = 1;
        mutex_unlock(&start_mutex);
        return 0;
+
 out3:
        if (oprofile_ops.shutdown)
                oprofile_ops.shutdown();
@@ -87,34 +98,53 @@ 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)
 {
        int err = -EINVAL;
+
        mutex_lock(&start_mutex);
+
        if (!is_setup)
                goto out;
 
-       err = 0; 
+       err = 0;
+
        if (oprofile_started)
                goto out;
+
        oprofile_reset_stats();
 
        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);
        return err;
 }
 
+
 /* echo 0>/dev/oprofile/enable */
 void oprofile_stop(void)
 {
@@ -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)
 {
@@ -172,17 +237,30 @@ int oprofile_set_backtrace(unsigned long val)
                goto out;
        }
 
-       backtrace_depth = val;
+       oprofile_backtrace_depth = val;
 
 out:
        mutex_unlock(&start_mutex);
        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) {
@@ -204,13 +282,13 @@ static void __exit oprofile_exit(void)
        oprofile_arch_exit();
 }
 
+
 module_init(oprofile_init);
 module_exit(oprofile_exit);
 
 module_param_named(timer, timer, int, 0644);
 MODULE_PARM_DESC(timer, "force use of timer interrupt");
+
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("John Levon <levon@movementarian.org>");
 MODULE_DESCRIPTION("OProfile system profiler");