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

#ifndef _LTTNG_TRACE_CLOCK_H
#define _LTTNG_TRACE_CLOCK_H

/*
 * wrapper/trace-clock.h
 *
 * Contains LTTng trace clock mapping to LTTng trace clock or mainline monotonic
 * clock. This wrapper depends on CONFIG_HIGH_RES_TIMERS=y.
 *
 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; only
 * version 2.1 of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#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
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	*/
f6c19f6e MD	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>
a82c63f1	35	#include "random.h"
f6c19f6e MD	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())
97ca2c54	46	return (u64) -EIO;
f6c19f6e MD	47
	48	ktime = ktime_get();
	49	return (u64) ktime.tv64;
	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
a3ccff4f	62	static inline u64 trace_clock_freq(void)
f6c19f6e	63	{
a3ccff4f	64	return (u64) NSEC_PER_SEC;
f6c19f6e MD	65	}
f6c19f6e MD	66
a82c63f1	67	static inline int trace_clock_uuid(char *uuid)
f6c19f6e	68	{
a82c63f1	69	return wrapper_get_bootid(uuid);
f6c19f6e MD	70	}
	71
	72	static inline int get_trace_clock(void)
	73	{
22f8d33a MD	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	*/
f6c19f6e MD	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");
cff67ebe MD	84	printk(KERN_WARNING "Integration of the LTTng 0.x trace clocks into LTTng 2.0 is planned\n");
cff67ebe MD	85	printk(KERN_WARNING "in a near future.\n");
f3bc08c5	86
f6c19f6e MD	87	return 0;
	88	}
	89
	90	static inline void put_trace_clock(void)
	91	{
	92	}
	93
	94	#endif /* CONFIG_HAVE_TRACE_CLOCK */
	95
a90917c3	96	#endif /* _LTTNG_TRACE_CLOCK_H */