1 #ifndef _LTTNG_TRACE_CLOCK_H
2 #define _LTTNG_TRACE_CLOCK_H
5 * wrapper/trace-clock.h
7 * Contains LTTng trace clock mapping to LTTng trace clock or mainline monotonic
8 * clock. This wrapper depends on CONFIG_HIGH_RES_TIMERS=y.
10 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
12 * This library is free software; you can redistribute it and/or
13 * modify it under the terms of the GNU Lesser General Public
14 * License as published by the Free Software Foundation; only
15 * version 2.1 of the License.
17 * This library is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 * Lesser General Public License for more details.
22 * You should have received a copy of the GNU Lesser General Public
23 * License along with this library; if not, write to the Free Software
24 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
27 #ifdef CONFIG_HAVE_TRACE_CLOCK
28 #include <linux/trace-clock.h>
29 #else /* CONFIG_HAVE_TRACE_CLOCK */
31 #include <linux/hardirq.h>
32 #include <linux/ktime.h>
33 #include <linux/time.h>
34 #include <linux/hrtimer.h>
35 #include <linux/version.h>
36 #include "../lttng-kernel-version.h"
39 #if LTTNG_KERNEL_RANGE(3,10,0, 3,10,14) || LTTNG_KERNEL_RANGE(3,11,0, 3,11,3)
40 #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."
43 static inline u64
trace_clock_monotonic_wrapper(void)
48 * Refuse to trace from NMIs with this wrapper, because an NMI could
49 * nest over the xtime write seqlock and deadlock.
55 return ktime_to_ns(ktime
);
58 static inline u32
trace_clock_read32(void)
60 return (u32
) trace_clock_monotonic_wrapper();
63 static inline u64
trace_clock_read64(void)
65 return (u64
) trace_clock_monotonic_wrapper();
68 static inline u64
trace_clock_freq(void)
70 return (u64
) NSEC_PER_SEC
;
73 static inline int trace_clock_uuid(char *uuid
)
75 return wrapper_get_bootid(uuid
);
78 static inline int get_trace_clock(void)
81 * LTTng: Using mainline kernel monotonic clock. NMIs will not be
82 * traced, and expect significant performance degradation compared to
83 * the LTTng trace clocks. Integration of the LTTng 0.x trace clocks
84 * into LTTng 2.0 is planned in a near future.
86 printk(KERN_WARNING
"LTTng: Using mainline kernel monotonic clock.\n");
87 printk(KERN_WARNING
" * NMIs will not be traced,\n");
88 printk(KERN_WARNING
" * expect significant performance degradation compared to the\n");
89 printk(KERN_WARNING
" LTTng trace clocks.\n");
90 printk(KERN_WARNING
"Integration of the LTTng 0.x trace clocks into LTTng 2.0 is planned\n");
91 printk(KERN_WARNING
"in a near future.\n");
96 static inline void put_trace_clock(void)
100 #endif /* CONFIG_HAVE_TRACE_CLOCK */
102 #endif /* _LTTNG_TRACE_CLOCK_H */
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