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

/*
 * Copyright (C) 2011 Mathieu Desnoyers (mathieu.desnoyers@efficios.com)
 *
 * 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.
 */

#ifndef _LTTNG_TRACE_CLOCK_H
#define _LTTNG_TRACE_CLOCK_H

#ifdef CONFIG_HAVE_TRACE_CLOCK
#include <linux/trace-clock.h>
#else /* CONFIG_HAVE_TRACE_CLOCK */

#include <linux/hardirq.h>
#include <linux/ktime.h>
#include <linux/time.h>
#include <linux/hrtimer.h>

static inline u64 trace_clock_monotonic_wrapper(void)
{
	ktime_t ktime;

	/*
	 * Refuse to trace from NMIs with this wrapper, because an NMI could
	 * nest over the xtime write seqlock and deadlock.
	 */
	if (in_nmi())
		return (u64) -EIO;

	ktime = ktime_get();
	return (u64) ktime.tv64;
}

static inline u32 trace_clock_read32(void)
{
	return (u32) trace_clock_monotonic_wrapper();
}

static inline u64 trace_clock_read64(void)
{
	return (u64) trace_clock_monotonic_wrapper();
}

static inline u64 trace_clock_freq(void)
{
	return (u64) NSEC_PER_SEC;
}

static inline const char *trace_clock_uuid(void)
{
	return "CLOCK_MONOTONIC";
}

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 "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;
}

static inline void put_trace_clock(void)
{
}

#endif /* CONFIG_HAVE_TRACE_CLOCK */

#endif /* _LTTNG_TRACE_CLOCK_H */
Commit	Line	Data
f6c19f6e MD	1	/*
	2	* Copyright (C) 2011 Mathieu Desnoyers (mathieu.desnoyers@efficios.com)
	3	*
	4	* Contains LTTng trace clock mapping to LTTng trace clock or mainline monotonic
	5	* clock. This wrapper depends on CONFIG_HIGH_RES_TIMERS=y.
	6	*
	7	* Dual LGPL v2.1/GPL v2 license.
	8	*/
	9
a90917c3 MD	10	#ifndef _LTTNG_TRACE_CLOCK_H
a90917c3 MD	11	#define _LTTNG_TRACE_CLOCK_H
f6c19f6e MD	12
	13	#ifdef CONFIG_HAVE_TRACE_CLOCK
	14	#include <linux/trace-clock.h>
	15	#else /* CONFIG_HAVE_TRACE_CLOCK */
	16
	17	#include <linux/hardirq.h>
	18	#include <linux/ktime.h>
	19	#include <linux/time.h>
	20	#include <linux/hrtimer.h>
	21
	22	static inline u64 trace_clock_monotonic_wrapper(void)
	23	{
	24	ktime_t ktime;
	25
	26	/*
	27	* Refuse to trace from NMIs with this wrapper, because an NMI could
	28	* nest over the xtime write seqlock and deadlock.
	29	*/
	30	if (in_nmi())
97ca2c54	31	return (u64) -EIO;
f6c19f6e MD	32
	33	ktime = ktime_get();
	34	return (u64) ktime.tv64;
	35	}
	36
	37	static inline u32 trace_clock_read32(void)
	38	{
	39	return (u32) trace_clock_monotonic_wrapper();
	40	}
	41
	42	static inline u64 trace_clock_read64(void)
	43	{
	44	return (u64) trace_clock_monotonic_wrapper();
	45	}
	46
a3ccff4f	47	static inline u64 trace_clock_freq(void)
f6c19f6e	48	{
a3ccff4f	49	return (u64) NSEC_PER_SEC;
f6c19f6e MD	50	}
f6c19f6e MD	51
a3ccff4f	52	static inline const char *trace_clock_uuid(void)
f6c19f6e	53	{
a3ccff4f	54	return "CLOCK_MONOTONIC";
f6c19f6e MD	55	}
	56
	57	static inline int get_trace_clock(void)
	58	{
22f8d33a MD	59	/*
	60	* LTTng: Using mainline kernel monotonic clock. NMIs will not be
	61	* traced, and expect significant performance degradation compared to
	62	* the LTTng trace clocks. Integration of the LTTng 0.x trace clocks
	63	* into LTTng 2.0 is planned in a near future.
	64	*/
f6c19f6e MD	65	printk(KERN_WARNING "LTTng: Using mainline kernel monotonic clock.\n");
	66	printk(KERN_WARNING " * NMIs will not be traced,\n");
	67	printk(KERN_WARNING " * expect significant performance degradation compared to the\n");
	68	printk(KERN_WARNING " LTTng trace clocks.\n");
cff67ebe MD	69	printk(KERN_WARNING "Integration of the LTTng 0.x trace clocks into LTTng 2.0 is planned\n");
cff67ebe MD	70	printk(KERN_WARNING "in a near future.\n");
f3bc08c5	71
f6c19f6e MD	72	return 0;
	73	}
	74
	75	static inline void put_trace_clock(void)
	76	{
	77	}
	78
	79	#endif /* CONFIG_HAVE_TRACE_CLOCK */
	80
a90917c3	81	#endif /* _LTTNG_TRACE_CLOCK_H */