[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>
#include "random.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 int trace_clock_uuid(char *uuid)
{
	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 "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>
a82c63f1	21	#include "random.h"
f6c19f6e MD	22
	23	static inline u64 trace_clock_monotonic_wrapper(void)
	24	{
	25	ktime_t ktime;
	26
	27	/*
	28	* Refuse to trace from NMIs with this wrapper, because an NMI could
	29	* nest over the xtime write seqlock and deadlock.
	30	*/
	31	if (in_nmi())
97ca2c54	32	return (u64) -EIO;
f6c19f6e MD	33
	34	ktime = ktime_get();
	35	return (u64) ktime.tv64;
	36	}
	37
	38	static inline u32 trace_clock_read32(void)
	39	{
	40	return (u32) trace_clock_monotonic_wrapper();
	41	}
	42
	43	static inline u64 trace_clock_read64(void)
	44	{
	45	return (u64) trace_clock_monotonic_wrapper();
	46	}
	47
a3ccff4f	48	static inline u64 trace_clock_freq(void)
f6c19f6e	49	{
a3ccff4f	50	return (u64) NSEC_PER_SEC;
f6c19f6e MD	51	}
f6c19f6e MD	52
a82c63f1	53	static inline int trace_clock_uuid(char *uuid)
f6c19f6e	54	{
a82c63f1	55	return wrapper_get_bootid(uuid);
f6c19f6e MD	56	}
	57
	58	static inline int get_trace_clock(void)
	59	{
22f8d33a MD	60	/*
	61	* LTTng: Using mainline kernel monotonic clock. NMIs will not be
	62	* traced, and expect significant performance degradation compared to
	63	* the LTTng trace clocks. Integration of the LTTng 0.x trace clocks
	64	* into LTTng 2.0 is planned in a near future.
	65	*/
f6c19f6e MD	66	printk(KERN_WARNING "LTTng: Using mainline kernel monotonic clock.\n");
	67	printk(KERN_WARNING " * NMIs will not be traced,\n");
	68	printk(KERN_WARNING " * expect significant performance degradation compared to the\n");
	69	printk(KERN_WARNING " LTTng trace clocks.\n");
cff67ebe MD	70	printk(KERN_WARNING "Integration of the LTTng 0.x trace clocks into LTTng 2.0 is planned\n");
cff67ebe MD	71	printk(KERN_WARNING "in a near future.\n");
f3bc08c5	72
f6c19f6e MD	73	return 0;
	74	}
	75
	76	static inline void put_trace_clock(void)
	77	{
	78	}
	79
	80	#endif /* CONFIG_HAVE_TRACE_CLOCK */
	81
a90917c3	82	#endif /* _LTTNG_TRACE_CLOCK_H */