Perf: Make per-process counters configurable
Add feature to enable/disable per-process tracecounters at run-time.
Change-Id: Id6a4c7a0ecd1f5add85464c6ed260860e15c4e3b
Signed-off-by: Sheetal Sahasrabudhe <sheetals@codeaurora.org>
diff --git a/arch/arm/mach-msm/perf_trace_counters.c b/arch/arm/mach-msm/perf_trace_counters.c
index d961994..65b0d28 100644
--- a/arch/arm/mach-msm/perf_trace_counters.c
+++ b/arch/arm/mach-msm/perf_trace_counters.c
@@ -10,9 +10,13 @@
* GNU General Public License for more details.
*/
#include <asm/thread_notify.h>
+#include <linux/uaccess.h>
+#include <linux/debugfs.h>
#define CREATE_TRACE_POINTS
#include "perf_trace_counters.h"
+static unsigned int tp_pid_state;
+
static int tracectr_notifier(struct notifier_block *self, unsigned long cmd,
void *v)
{
@@ -34,9 +38,80 @@
.notifier_call = tracectr_notifier,
};
+static void enable_tp_pid(void)
+{
+ if (tp_pid_state == 0) {
+ tp_pid_state = 1;
+ thread_register_notifier(&tracectr_notifier_block);
+ }
+}
+
+static void disable_tp_pid(void)
+{
+ if (tp_pid_state == 1) {
+ tp_pid_state = 0;
+ thread_unregister_notifier(&tracectr_notifier_block);
+ }
+}
+
+static ssize_t read_enabled_perftp_file_bool(struct file *file,
+ char __user *user_buf, size_t count, loff_t *ppos)
+{
+ char buf[2];
+ buf[1] = '\n';
+ if (tp_pid_state == 0)
+ buf[0] = '0';
+ else
+ buf[0] = '1';
+ return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
+}
+
+static ssize_t write_enabled_perftp_file_bool(struct file *file,
+ const char __user *user_buf, size_t count, loff_t *ppos)
+{
+ char buf[32];
+ size_t buf_size;
+
+ buf_size = min(count, (sizeof(buf)-1));
+ if (copy_from_user(buf, user_buf, buf_size))
+ return -EFAULT;
+ switch (buf[0]) {
+ case 'y':
+ case 'Y':
+ case '1':
+ enable_tp_pid();
+ break;
+ case 'n':
+ case 'N':
+ case '0':
+ disable_tp_pid();
+ break;
+ }
+
+ return count;
+}
+
+static const struct file_operations fops_perftp = {
+ .read = read_enabled_perftp_file_bool,
+ .write = write_enabled_perftp_file_bool,
+ .llseek = default_llseek,
+};
+
int __init init_tracecounters(void)
{
- thread_register_notifier(&tracectr_notifier_block);
+ struct dentry *dir;
+ struct dentry *file;
+ unsigned int value = 1;
+
+ dir = debugfs_create_dir("perf_debug_tp", NULL);
+ if (!dir)
+ return -ENOMEM;
+ file = debugfs_create_file("enabled", 0777, dir,
+ &value, &fops_perftp);
+ if (!file) {
+ debugfs_remove(dir);
+ return -ENOMEM;
+ }
return 0;
}
late_initcall(init_tracecounters);