Index: linux-2.6-git-2.6.31-bisect2/fs/read_write.c
===================================================================
--- linux-2.6-git-2.6.31-bisect2.orig/fs/read_write.c
+++ linux-2.6-git-2.6.31-bisect2/fs/read_write.c
@@ -249,25 +249,37 @@ static void wait_on_retry_sync_kiocb(str
 	__set_current_state(TASK_RUNNING);
 }
 
+unsigned long perf_count_do_sync_read_calls_aio_read = 0;
+unsigned long perf_tsum_do_sync_read_calls_aio_read = 0;
+unsigned long perf_count_do_sync_read_calls_wait_on_sync_kiocb = 0;
+unsigned long perf_tsum_do_sync_read_calls_wait_on_sync_kiocb = 0;
 ssize_t do_sync_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
 {
 	struct iovec iov = { .iov_base = buf, .iov_len = len };
 	struct kiocb kiocb;
 	ssize_t ret;
+	ktime_t tv64_pre;
 
 	init_sync_kiocb(&kiocb, filp);
 	kiocb.ki_pos = *ppos;
 	kiocb.ki_left = len;
 
 	for (;;) {
+		perf_count_do_sync_read_calls_aio_read++;
+		tv64_pre = ktime_get();
 		ret = filp->f_op->aio_read(&kiocb, &iov, 1, kiocb.ki_pos);
+		perf_tsum_do_sync_read_calls_aio_read += ktime_sub(ktime_get(),tv64_pre).tv64;
 		if (ret != -EIOCBRETRY)
 			break;
 		wait_on_retry_sync_kiocb(&kiocb);
 	}
 
-	if (-EIOCBQUEUED == ret)
+	if (-EIOCBQUEUED == ret) {
+		perf_count_do_sync_read_calls_wait_on_sync_kiocb++;
+		tv64_pre = ktime_get();
 		ret = wait_on_sync_kiocb(&kiocb);
+		perf_tsum_do_sync_read_calls_wait_on_sync_kiocb += ktime_sub(ktime_get(),tv64_pre).tv64;
+	}
 	*ppos = kiocb.ki_pos;
 	return ret;
 }
Index: linux-2.6-git-2.6.31-bisect2/kernel/sysctl.c
===================================================================
--- linux-2.6-git-2.6.31-bisect2.orig/kernel/sysctl.c
+++ linux-2.6-git-2.6.31-bisect2/kernel/sysctl.c
@@ -257,6 +257,10 @@ extern unsigned long perf_count_pages_di
 extern unsigned long perf_count_failed_pages_direct_reclaim;
 extern unsigned long perf_count_do_generic_file_read_calls_page_cache_alloc_cold;
 extern unsigned long perf_tsum_do_generic_file_read_calls_page_cache_alloc_cold;
+extern unsigned long perf_count_do_sync_read_calls_aio_read;
+extern unsigned long perf_tsum_do_sync_read_calls_aio_read;
+extern unsigned long perf_count_do_sync_read_calls_wait_on_sync_kiocb;
+extern unsigned long perf_tsum_do_sync_read_calls_wait_on_sync_kiocb;
 static struct ctl_table perf_table[] = {
 	{
 		.ctl_name	= CTL_UNNUMBERED,
@@ -297,6 +301,38 @@ static struct ctl_table perf_table[] = {
 		.maxlen		= sizeof(unsigned long),
 		.mode           = 0666,
 		.proc_handler   = &proc_doulongvec_minmax,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname       = "perf_count_do_sync_read_calls_aio_read",
+		.data           = &perf_count_do_sync_read_calls_aio_read,
+		.maxlen		= sizeof(unsigned long),
+		.mode           = 0666,
+		.proc_handler   = &proc_doulongvec_minmax,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname       = "perf_tsum_do_sync_read_calls_aio_read",
+		.data           = &perf_tsum_do_sync_read_calls_aio_read,
+		.maxlen		= sizeof(unsigned long),
+		.mode           = 0666,
+		.proc_handler   = &proc_doulongvec_minmax,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname       = "perf_count_do_sync_read_calls_wait_on_sync_kiocb",
+		.data           = &perf_count_do_sync_read_calls_wait_on_sync_kiocb,
+		.maxlen		= sizeof(unsigned long),
+		.mode           = 0666,
+		.proc_handler   = &proc_doulongvec_minmax,
+	},
+	{
+		.ctl_name	= CTL_UNNUMBERED,
+		.procname       = "perf_tsum_do_sync_read_calls_wait_on_sync_kiocb",
+		.data           = &perf_tsum_do_sync_read_calls_wait_on_sync_kiocb,
+		.maxlen		= sizeof(unsigned long),
+		.mode           = 0666,
+		.proc_handler   = &proc_doulongvec_minmax,
 	},
 	{ .ctl_name = 0 }
 };