xref: /freebsd/sys/sys/gmon.h (revision 0957b409)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1982, 1986, 1992, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the University nor the names of its contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  *
31  *	@(#)gmon.h	8.2 (Berkeley) 1/4/94
32  * $FreeBSD$
33  */
34 
35 #ifndef _SYS_GMON_H_
36 #define _SYS_GMON_H_
37 
38 #include <machine/profile.h>
39 
40 /*
41  * Structure prepended to gmon.out profiling data file.
42  */
43 struct gmonhdr {
44 	u_long	lpc;		/* base pc address of sample buffer */
45 	u_long	hpc;		/* max pc address of sampled buffer */
46 	int	ncnt;		/* size of sample buffer (plus this header) */
47 	int	version;	/* version number */
48 	int	profrate;	/* profiling clock rate */
49 	int	histcounter_type; /* size (in bits) and sign of HISTCOUNTER */
50 	int	spare[2];	/* reserved */
51 };
52 #define GMONVERSION	0x00051879
53 
54 /*
55  * Type of histogram counters used in the kernel.
56  */
57 #ifdef GPROF4
58 #define	HISTCOUNTER	int64_t
59 #else
60 #define	HISTCOUNTER	unsigned short
61 #endif
62 
63 /*
64  * Fraction of text space to allocate for histogram counters.
65  * We allocate counters at the same or higher density as function
66  * addresses, so that each counter belongs to a unique function.
67  * A lower density of counters would give less resolution but a
68  * higher density would be wasted.
69  */
70 #define	HISTFRACTION	(FUNCTION_ALIGNMENT / sizeof(HISTCOUNTER) == 0 \
71 			 ? 1 : FUNCTION_ALIGNMENT / sizeof(HISTCOUNTER))
72 
73 /*
74  * Fraction of text space to allocate for from hash buckets.
75  * The value of HASHFRACTION is based on the minimum number of bytes
76  * of separation between two subroutine call points in the object code.
77  * Given MIN_SUBR_SEPARATION bytes of separation the value of
78  * HASHFRACTION is calculated as:
79  *
80  *	HASHFRACTION = MIN_SUBR_SEPARATION / (2 * sizeof(short) - 1);
81  *
82  * For example, on the VAX, the shortest two call sequence is:
83  *
84  *	calls	$0,(r0)
85  *	calls	$0,(r0)
86  *
87  * which is separated by only three bytes, thus HASHFRACTION is
88  * calculated as:
89  *
90  *	HASHFRACTION = 3 / (2 * 2 - 1) = 1
91  *
92  * Note that the division above rounds down, thus if MIN_SUBR_FRACTION
93  * is less than three, this algorithm will not work!
94  *
95  * In practice, however, call instructions are rarely at a minimal
96  * distance.  Hence, we will define HASHFRACTION to be 2 across all
97  * architectures.  This saves a reasonable amount of space for
98  * profiling data structures without (in practice) sacrificing
99  * any granularity.
100  */
101 /*
102  * XXX I think the above analysis completely misses the point.  I think
103  * the point is that addresses in different functions must hash to
104  * different values.  Since the hash is essentially division by
105  * sizeof(unsigned short), the correct formula is:
106  *
107  * 	HASHFRACTION = MIN_FUNCTION_ALIGNMENT / sizeof(unsigned short)
108  *
109  * Note that he unsigned short here has nothing to do with the one for
110  * HISTFRACTION.
111  *
112  * Hash collisions from a two call sequence don't matter.  They get
113  * handled like collisions for calls to different addresses from the
114  * same address through a function pointer.
115  */
116 #define	HASHFRACTION	(FUNCTION_ALIGNMENT / sizeof(unsigned short) == 0 \
117 			 ? 1 : FUNCTION_ALIGNMENT / sizeof(unsigned short))
118 
119 /*
120  * percent of text space to allocate for tostructs with a minimum.
121  */
122 #define ARCDENSITY	2
123 #define MINARCS		50
124 
125 /*
126  * Limit on the number of arcs to so that arc numbers can be stored in
127  * `*froms' and stored and incremented without overflow in links.
128  */
129 #define MAXARCS		(((u_long)1 << (8 * sizeof(u_short))) - 2)
130 
131 struct tostruct {
132 	u_long	selfpc;
133 	long	count;
134 	u_short	link;
135 	u_short pad;
136 };
137 
138 /*
139  * a raw arc, with pointers to the calling site and
140  * the called site and a count.
141  */
142 struct rawarc {
143 	u_long	raw_frompc;
144 	u_long	raw_selfpc;
145 	long	raw_count;
146 };
147 
148 /*
149  * general rounding functions.
150  */
151 #define ROUNDDOWN(x,y)	rounddown(x,y)
152 #define ROUNDUP(x,y)	roundup(x,y)
153 
154 /*
155  * The profiling data structures are housed in this structure.
156  */
157 struct gmonparam {
158 	int		state;
159 	HISTCOUNTER	*kcount;
160 	u_long		kcountsize;
161 	u_short		*froms;
162 	u_long		fromssize;
163 	struct tostruct	*tos;
164 	u_long		tossize;
165 	long		tolimit;
166 	uintfptr_t	lowpc;
167 	uintfptr_t	highpc;
168 	u_long		textsize;
169 	u_long		hashfraction;
170 	int		profrate;	/* XXX wrong type to match gmonhdr */
171 	HISTCOUNTER	*cputime_count;
172 	int		cputime_overhead;
173 	HISTCOUNTER	*mcount_count;
174 	int		mcount_overhead;
175 	int		mcount_post_overhead;
176 	int		mcount_pre_overhead;
177 	HISTCOUNTER	*mexitcount_count;
178 	int		mexitcount_overhead;
179 	int		mexitcount_post_overhead;
180 	int		mexitcount_pre_overhead;
181 	int		histcounter_type;
182 };
183 extern struct gmonparam _gmonparam;
184 
185 /*
186  * Possible states of profiling.
187  */
188 #define	GMON_PROF_ON	0
189 #define	GMON_PROF_BUSY	1
190 #define	GMON_PROF_ERROR	2
191 #define	GMON_PROF_OFF	3
192 #define	GMON_PROF_HIRES	4
193 
194 /*
195  * Sysctl definitions for extracting profiling information from the kernel.
196  */
197 #define	GPROF_STATE	0	/* int: profiling enabling variable */
198 #define	GPROF_COUNT	1	/* struct: profile tick count buffer */
199 #define	GPROF_FROMS	2	/* struct: from location hash bucket */
200 #define	GPROF_TOS	3	/* struct: destination/count structure */
201 #define	GPROF_GMONPARAM	4	/* struct: profiling parameters (see above) */
202 
203 #ifdef _KERNEL
204 
205 #define	KCOUNT(p,index) \
206 	((p)->kcount[(index) / (HISTFRACTION * sizeof(HISTCOUNTER))])
207 #define	PC_TO_I(p, pc)	((uintfptr_t)(pc) - (uintfptr_t)(p)->lowpc)
208 
209 #ifdef GUPROF
210 
211 #define	CALIB_SCALE	1000
212 
213 extern int	cputime_bias;
214 
215 int	cputime(void);
216 void	nullfunc_loop_profiled(void);
217 void	nullfunc_profiled(void);
218 void	startguprof(struct gmonparam *p);
219 void	stopguprof(struct gmonparam *p);
220 
221 #else /* !GUPROF */
222 
223 #define	startguprof(p)
224 #define	stopguprof(p)
225 
226 #endif /* GUPROF */
227 
228 void	empty_loop(void);
229 void	kmupetext(uintfptr_t nhighpc);
230 void	mexitcount(uintfptr_t selfpc);
231 void	nullfunc(void);
232 void	nullfunc_loop(void);
233 
234 #else /* !_KERNEL */
235 
236 #include <sys/cdefs.h>
237 
238 __BEGIN_DECLS
239 void	moncontrol(int);
240 void	monstartup(u_long, u_long);
241 __END_DECLS
242 
243 #endif /* _KERNEL */
244 
245 #endif /* !_SYS_GMON_H_ */
246