LTTng trace-clock: shrink kernel blacklist

[lttng-modules.git] / wrapper / trace-clock.h

diff --git a/wrapper/trace-clock.h b/wrapper/trace-clock.h
index b2a90bd462e292f0f3f4eed6dd021da9b39138d0..d31141dc463f8f629279a42fc976f8c605cf8cac 100644 (file)
--- a/wrapper/trace-clock.h
+++ b/wrapper/trace-clock.h
@@ -1,15 +1,29 @@
+#ifndef _LTTNG_TRACE_CLOCK_H
+#define _LTTNG_TRACE_CLOCK_H
+
 /*
- * Copyright (C) 2011 Mathieu Desnoyers (mathieu.desnoyers@efficios.com)
+ * wrapper/trace-clock.h
  *
  * Contains LTTng trace clock mapping to LTTng trace clock or mainline monotonic
  * clock. This wrapper depends on CONFIG_HIGH_RES_TIMERS=y.
  *
- * Dual LGPL v2.1/GPL v2 license.
+ * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
-#ifndef _LTT_TRACE_CLOCK_H
-#define _LTT_TRACE_CLOCK_H
-
 #ifdef CONFIG_HAVE_TRACE_CLOCK
 #include <linux/trace-clock.h>
 #else /* CONFIG_HAVE_TRACE_CLOCK */
@@ -18,6 +32,13 @@
 #include <linux/ktime.h>
 #include <linux/time.h>
 #include <linux/hrtimer.h>
+#include <linux/version.h>
+#include "../lttng-kernel-version.h"
+#include "random.h"
+
+#if LTTNG_KERNEL_RANGE(3,10,0, 3,10,13) || LTTNG_KERNEL_RANGE(3,11,0, 3,11,2)
+#error "Linux kernels 3.10 and 3.11 introduce a deadlock in the timekeeping subsystem. Fixed by commit 7bd36014460f793c19e7d6c94dab67b0afcfcb7f \"timekeeping: Fix HRTICK related deadlock from ntp lock changes\" in Linux."
+#endif
 
 static inline u64 trace_clock_monotonic_wrapper(void)
 {
@@ -31,7 +52,7 @@ static inline u64 trace_clock_monotonic_wrapper(void)
                return (u64) -EIO;
 
        ktime = ktime_get();
-       return (u64) ktime.tv64;
+       return ktime_to_ns(ktime);
 }
 
 static inline u32 trace_clock_read32(void)
@@ -44,27 +65,30 @@ static inline u64 trace_clock_read64(void)
        return (u64) trace_clock_monotonic_wrapper();
 }
 
-static inline u64 trace_clock_frequency(void)
+static inline u64 trace_clock_freq(void)
 {
-       return (u64)NSEC_PER_SEC;
+       return (u64) NSEC_PER_SEC;
 }
 
-static inline u32 trace_clock_freq_scale(void)
+static inline int trace_clock_uuid(char *uuid)
 {
-       return 1;
+       return wrapper_get_bootid(uuid);
 }
 
 static inline int get_trace_clock(void)
 {
+       /*
+        * LTTng: Using mainline kernel monotonic clock. NMIs will not be
+        * traced, and expect significant performance degradation compared to
+        * the LTTng trace clocks. Integration of the LTTng 0.x trace clocks
+        * into LTTng 2.0 is planned in a near future.
+        */
        printk(KERN_WARNING "LTTng: Using mainline kernel monotonic clock.\n");
        printk(KERN_WARNING "  * NMIs will not be traced,\n");
        printk(KERN_WARNING "  * expect significant performance degradation compared to the\n");
        printk(KERN_WARNING "    LTTng trace clocks.\n");
-       printk(KERN_WARNING "You should consider deploying a kernel with the the LTTng kernel\n");
-       printk(KERN_WARNING "patches, or, better, ask the Linux tracing maintainers to integrate\n");
-       printk(KERN_WARNING "them if you care deeply about this.\n");
-
-#warning "LTTng: Using mainline kernel monotonic clock. NMIs will not be traced, and expect significant performance degradation compared to the LTTng trace clocks. You should consider deploying a kernel with the the LTTng kernel patches, or, better, ask the Linux tracing maintainers to integrate them if you care deeply about this."
+       printk(KERN_WARNING "Integration of the LTTng 0.x trace clocks into LTTng 2.0 is planned\n");
+       printk(KERN_WARNING "in a near future.\n");
 
        return 0;
 }
@@ -75,4 +99,4 @@ static inline void put_trace_clock(void)
 
 #endif /* CONFIG_HAVE_TRACE_CLOCK */
 
-#endif /* _LTT_TRACE_CLOCK_H */
+#endif /* _LTTNG_TRACE_CLOCK_H */