| 1 | #ifndef _LTTNG_TRACE_CLOCK_H |
| 2 | #define _LTTNG_TRACE_CLOCK_H |
| 3 | |
| 4 | /* |
| 5 | * wrapper/trace-clock.h |
| 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 | * |
| 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 |
| 25 | */ |
| 26 | |
| 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> |
| 35 | #include "random.h" |
| 36 | |
| 37 | static inline u64 trace_clock_monotonic_wrapper(void) |
| 38 | { |
| 39 | ktime_t ktime; |
| 40 | |
| 41 | /* |
| 42 | * Refuse to trace from NMIs with this wrapper, because an NMI could |
| 43 | * nest over the xtime write seqlock and deadlock. |
| 44 | */ |
| 45 | if (in_nmi()) |
| 46 | return (u64) -EIO; |
| 47 | |
| 48 | ktime = ktime_get(); |
| 49 | return ktime_to_ns(ktime); |
| 50 | } |
| 51 | |
| 52 | static inline u32 trace_clock_read32(void) |
| 53 | { |
| 54 | return (u32) trace_clock_monotonic_wrapper(); |
| 55 | } |
| 56 | |
| 57 | static inline u64 trace_clock_read64(void) |
| 58 | { |
| 59 | return (u64) trace_clock_monotonic_wrapper(); |
| 60 | } |
| 61 | |
| 62 | static inline u64 trace_clock_freq(void) |
| 63 | { |
| 64 | return (u64) NSEC_PER_SEC; |
| 65 | } |
| 66 | |
| 67 | static inline int trace_clock_uuid(char *uuid) |
| 68 | { |
| 69 | return wrapper_get_bootid(uuid); |
| 70 | } |
| 71 | |
| 72 | static inline int get_trace_clock(void) |
| 73 | { |
| 74 | /* |
| 75 | * LTTng: Using mainline kernel monotonic clock. NMIs will not be |
| 76 | * traced, and expect significant performance degradation compared to |
| 77 | * the LTTng trace clocks. Integration of the LTTng 0.x trace clocks |
| 78 | * into LTTng 2.0 is planned in a near future. |
| 79 | */ |
| 80 | printk(KERN_WARNING "LTTng: Using mainline kernel monotonic clock.\n"); |
| 81 | printk(KERN_WARNING " * NMIs will not be traced,\n"); |
| 82 | printk(KERN_WARNING " * expect significant performance degradation compared to the\n"); |
| 83 | printk(KERN_WARNING " LTTng trace clocks.\n"); |
| 84 | printk(KERN_WARNING "Integration of the LTTng 0.x trace clocks into LTTng 2.0 is planned\n"); |
| 85 | printk(KERN_WARNING "in a near future.\n"); |
| 86 | |
| 87 | return 0; |
| 88 | } |
| 89 | |
| 90 | static inline void put_trace_clock(void) |
| 91 | { |
| 92 | } |
| 93 | |
| 94 | #endif /* CONFIG_HAVE_TRACE_CLOCK */ |
| 95 | |
| 96 | #endif /* _LTTNG_TRACE_CLOCK_H */ |