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886d51a3 MD |
1 | #ifndef _LTTNG_TRACE_CLOCK_H |
2 | #define _LTTNG_TRACE_CLOCK_H | |
3 | ||
f6c19f6e | 4 | /* |
886d51a3 | 5 | * wrapper/trace-clock.h |
f6c19f6e MD |
6 | * |
7 | * Contains LTTng trace clock mapping to LTTng trace clock or mainline monotonic | |
8 | * clock. This wrapper depends on CONFIG_HIGH_RES_TIMERS=y. | |
9 | * | |
886d51a3 MD |
10 | * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com> |
11 | * | |
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. | |
16 | * | |
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. | |
21 | * | |
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 | |
f6c19f6e MD |
25 | */ |
26 | ||
f6c19f6e MD |
27 | #ifdef CONFIG_HAVE_TRACE_CLOCK |
28 | #include <linux/trace-clock.h> | |
29 | #else /* CONFIG_HAVE_TRACE_CLOCK */ | |
30 | ||
31 | #include <linux/hardirq.h> | |
32 | #include <linux/ktime.h> | |
33 | #include <linux/time.h> | |
34 | #include <linux/hrtimer.h> | |
fc8216ae | 35 | #include <linux/version.h> |
a82c63f1 | 36 | #include "random.h" |
f6c19f6e | 37 | |
fc8216ae MD |
38 | #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,10,0)) |
39 | #error "Linux kernels 3.10 and 3.11 introduce a deadlock in the timekeeping subsystem. See http://lkml.kernel.org/r/1378943457-27314-1-git-send-email-john.stultz@linaro.org for details. Awaiting patch merge into Linux master, stable-3.10 and stable-3.11 for fine-grained kernel version blacklisting." | |
40 | #endif | |
41 | ||
f6c19f6e MD |
42 | static inline u64 trace_clock_monotonic_wrapper(void) |
43 | { | |
44 | ktime_t ktime; | |
45 | ||
46 | /* | |
47 | * Refuse to trace from NMIs with this wrapper, because an NMI could | |
48 | * nest over the xtime write seqlock and deadlock. | |
49 | */ | |
50 | if (in_nmi()) | |
97ca2c54 | 51 | return (u64) -EIO; |
f6c19f6e MD |
52 | |
53 | ktime = ktime_get(); | |
cfaf9f3d | 54 | return ktime_to_ns(ktime); |
f6c19f6e MD |
55 | } |
56 | ||
57 | static inline u32 trace_clock_read32(void) | |
58 | { | |
59 | return (u32) trace_clock_monotonic_wrapper(); | |
60 | } | |
61 | ||
62 | static inline u64 trace_clock_read64(void) | |
63 | { | |
64 | return (u64) trace_clock_monotonic_wrapper(); | |
65 | } | |
66 | ||
a3ccff4f | 67 | static inline u64 trace_clock_freq(void) |
f6c19f6e | 68 | { |
a3ccff4f | 69 | return (u64) NSEC_PER_SEC; |
f6c19f6e MD |
70 | } |
71 | ||
a82c63f1 | 72 | static inline int trace_clock_uuid(char *uuid) |
f6c19f6e | 73 | { |
a82c63f1 | 74 | return wrapper_get_bootid(uuid); |
f6c19f6e MD |
75 | } |
76 | ||
77 | static inline int get_trace_clock(void) | |
78 | { | |
22f8d33a MD |
79 | /* |
80 | * LTTng: Using mainline kernel monotonic clock. NMIs will not be | |
81 | * traced, and expect significant performance degradation compared to | |
82 | * the LTTng trace clocks. Integration of the LTTng 0.x trace clocks | |
83 | * into LTTng 2.0 is planned in a near future. | |
84 | */ | |
f6c19f6e MD |
85 | printk(KERN_WARNING "LTTng: Using mainline kernel monotonic clock.\n"); |
86 | printk(KERN_WARNING " * NMIs will not be traced,\n"); | |
87 | printk(KERN_WARNING " * expect significant performance degradation compared to the\n"); | |
88 | printk(KERN_WARNING " LTTng trace clocks.\n"); | |
cff67ebe MD |
89 | printk(KERN_WARNING "Integration of the LTTng 0.x trace clocks into LTTng 2.0 is planned\n"); |
90 | printk(KERN_WARNING "in a near future.\n"); | |
f3bc08c5 | 91 | |
f6c19f6e MD |
92 | return 0; |
93 | } | |
94 | ||
95 | static inline void put_trace_clock(void) | |
96 | { | |
97 | } | |
98 | ||
99 | #endif /* CONFIG_HAVE_TRACE_CLOCK */ | |
100 | ||
a90917c3 | 101 | #endif /* _LTTNG_TRACE_CLOCK_H */ |