From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Mon, 12 Jan 2015 22:11:32 +0000 (-0500)
Subject: Fix: add ustctl_has_perf_counters
X-Git-Tag: v2.6.0~3
X-Git-Url: http://git.liburcu.org/?p=lttng-ust.git;a=commitdiff_plain;h=1fd7b0dab12b14e63dfe0587cd4c703f5114919a

Fix: add ustctl_has_perf_counters

Allow sessiond to report whether performance counters are supported by
UST on the architecture as soon as the user try to enable a perf counter
context.

Fixes #851

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/include/lttng/ust-ctl.h b/include/lttng/ust-ctl.h
index 40e831e5..8e60f0d8 100644
--- a/include/lttng/ust-ctl.h
+++ b/include/lttng/ust-ctl.h
@@ -238,6 +238,9 @@ int ustctl_get_stream_id(struct ustctl_consumer_stream *stream,
 int ustctl_get_current_timestamp(struct ustctl_consumer_stream *stream,
 		uint64_t *ts);
 
+/* returns whether UST has perf counters support. */
+int ustctl_has_perf_counters(void);
+
 /* event registry management */
 
 enum ustctl_socket_type {
diff --git a/liblttng-ust-ctl/ustctl.c b/liblttng-ust-ctl/ustctl.c
index 195f29c0..b44d9e34 100644
--- a/liblttng-ust-ctl/ustctl.c
+++ b/liblttng-ust-ctl/ustctl.c
@@ -1639,6 +1639,22 @@ int ustctl_get_current_timestamp(struct ustctl_consumer_stream *stream,
 	return client_cb->current_timestamp(buf, handle, ts);
 }
 
+#if defined(__x86_64__) || defined(__i386__)
+
+int ustctl_has_perf_counters(void)
+{
+	return 1;
+}
+
+#else
+
+int ustctl_has_perf_counters(void)
+{
+	return 0;
+}
+
+#endif
+
 /*
  * Returns 0 on success, negative error value on error.
  */