xref: /freebsd-14.2/sys/sys/gmon.h (revision 2ff63af9)
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  */
33 
34 #ifndef _SYS_GMON_H_
35 #define _SYS_GMON_H_
36 
37 #include <machine/profile.h>
38 
39 /*
40  * Structure prepended to gmon.out profiling data file.
41  */
42 struct gmonhdr {
43 	u_long	lpc;		/* base pc address of sample buffer */
44 	u_long	hpc;		/* max pc address of sampled buffer */
45 	int	ncnt;		/* size of sample buffer (plus this header) */
46 	int	version;	/* version number */
47 	int	profrate;	/* profiling clock rate */
48 	int	histcounter_type; /* size (in bits) and sign of HISTCOUNTER */
49 	int	spare[2];	/* reserved */
50 };
51 #define GMONVERSION	0x00051879
52 
53 /*
54  * Type of histogram counters used in the kernel.
55  */
56 #ifdef GPROF4
57 #define	HISTCOUNTER	int64_t
58 #else
59 #define	HISTCOUNTER	unsigned short
60 #endif
61 
62 /*
63  * Fraction of text space to allocate for histogram counters.
64  * We allocate counters at the same or higher density as function
65  * addresses, so that each counter belongs to a unique function.
66  * A lower density of counters would give less resolution but a
67  * higher density would be wasted.
68  */
69 #define	HISTFRACTION	(FUNCTION_ALIGNMENT / sizeof(HISTCOUNTER) == 0 \
70 			 ? 1 : FUNCTION_ALIGNMENT / sizeof(HISTCOUNTER))
71 
72 /*
73  * Fraction of text space to allocate for from hash buckets.
74  * The value of HASHFRACTION is based on the minimum number of bytes
75  * of separation between two subroutine call points in the object code.
76  * Given MIN_SUBR_SEPARATION bytes of separation the value of
77  * HASHFRACTION is calculated as:
78  *
79  *	HASHFRACTION = MIN_SUBR_SEPARATION / (2 * sizeof(short) - 1);
80  *
81  * For example, on the VAX, the shortest two call sequence is:
82  *
83  *	calls	$0,(r0)
84  *	calls	$0,(r0)
85  *
86  * which is separated by only three bytes, thus HASHFRACTION is
87  * calculated as:
88  *
89  *	HASHFRACTION = 3 / (2 * 2 - 1) = 1
90  *
91  * Note that the division above rounds down, thus if MIN_SUBR_FRACTION
92  * is less than three, this algorithm will not work!
93  *
94  * In practice, however, call instructions are rarely at a minimal
95  * distance.  Hence, we will define HASHFRACTION to be 2 across all
96  * architectures.  This saves a reasonable amount of space for
97  * profiling data structures without (in practice) sacrificing
98  * any granularity.
99  */
100 /*
101  * XXX I think the above analysis completely misses the point.  I think
102  * the point is that addresses in different functions must hash to
103  * different values.  Since the hash is essentially division by
104  * sizeof(unsigned short), the correct formula is:
105  *
106  * 	HASHFRACTION = MIN_FUNCTION_ALIGNMENT / sizeof(unsigned short)
107  *
108  * Note that he unsigned short here has nothing to do with the one for
109  * HISTFRACTION.
110  *
111  * Hash collisions from a two call sequence don't matter.  They get
112  * handled like collisions for calls to different addresses from the
113  * same address through a function pointer.
114  */
115 #define	HASHFRACTION	(FUNCTION_ALIGNMENT / sizeof(unsigned short) == 0 \
116 			 ? 1 : FUNCTION_ALIGNMENT / sizeof(unsigned short))
117 
118 /*
119  * percent of text space to allocate for tostructs with a minimum.
120  */
121 #define ARCDENSITY	2
122 #define MINARCS		50
123 
124 /*
125  * Limit on the number of arcs to so that arc numbers can be stored in
126  * `*froms' and stored and incremented without overflow in links.
127  */
128 #define MAXARCS		(((u_long)1 << (8 * sizeof(u_short))) - 2)
129 
130 struct tostruct {
131 	u_long	selfpc;
132 	long	count;
133 	u_short	link;
134 	u_short pad;
135 };
136 
137 /*
138  * a raw arc, with pointers to the calling site and
139  * the called site and a count.
140  */
141 struct rawarc {
142 	u_long	raw_frompc;
143 	u_long	raw_selfpc;
144 	long	raw_count;
145 };
146 
147 /*
148  * general rounding functions.
149  */
150 #define ROUNDDOWN(x,y)	rounddown(x,y)
151 #define ROUNDUP(x,y)	roundup(x,y)
152 
153 /*
154  * The profiling data structures are housed in this structure.
155  */
156 struct gmonparam {
157 	int		state;
158 	HISTCOUNTER	*kcount;
159 	u_long		kcountsize;
160 	u_short		*froms;
161 	u_long		fromssize;
162 	struct tostruct	*tos;
163 	u_long		tossize;
164 	long		tolimit;
165 	uintfptr_t	lowpc;
166 	uintfptr_t	highpc;
167 	u_long		textsize;
168 	u_long		hashfraction;
169 	int		profrate;	/* XXX wrong type to match gmonhdr */
170 	HISTCOUNTER	*cputime_count;
171 	int		cputime_overhead;
172 	HISTCOUNTER	*mcount_count;
173 	int		mcount_overhead;
174 	int		mcount_post_overhead;
175 	int		mcount_pre_overhead;
176 	HISTCOUNTER	*mexitcount_count;
177 	int		mexitcount_overhead;
178 	int		mexitcount_post_overhead;
179 	int		mexitcount_pre_overhead;
180 	int		histcounter_type;
181 };
182 extern struct gmonparam _gmonparam;
183 
184 /*
185  * Possible states of profiling.
186  */
187 #define	GMON_PROF_ON	0
188 #define	GMON_PROF_BUSY	1
189 #define	GMON_PROF_ERROR	2
190 #define	GMON_PROF_OFF	3
191 #define	GMON_PROF_HIRES	4
192 
193 /*
194  * Sysctl definitions for extracting profiling information from the kernel.
195  */
196 #define	GPROF_STATE	0	/* int: profiling enabling variable */
197 #define	GPROF_COUNT	1	/* struct: profile tick count buffer */
198 #define	GPROF_FROMS	2	/* struct: from location hash bucket */
199 #define	GPROF_TOS	3	/* struct: destination/count structure */
200 #define	GPROF_GMONPARAM	4	/* struct: profiling parameters (see above) */
201 
202 #ifdef _KERNEL
203 
204 #define	KCOUNT(p,index) \
205 	((p)->kcount[(index) / (HISTFRACTION * sizeof(HISTCOUNTER))])
206 #define	PC_TO_I(p, pc)	((uintfptr_t)(pc) - (uintfptr_t)(p)->lowpc)
207 
208 #ifdef GUPROF
209 
210 #define	CALIB_SCALE	1000
211 
212 extern int	cputime_bias;
213 
214 int	cputime(void);
215 void	nullfunc_loop_profiled(void);
216 void	nullfunc_profiled(void);
217 void	startguprof(struct gmonparam *p);
218 void	stopguprof(struct gmonparam *p);
219 
220 #else /* !GUPROF */
221 
222 #define	startguprof(p)
223 #define	stopguprof(p)
224 
225 #endif /* GUPROF */
226 
227 void	empty_loop(void);
228 void	kmupetext(uintfptr_t nhighpc);
229 void	mexitcount(uintfptr_t selfpc);
230 void	nullfunc(void);
231 void	nullfunc_loop(void);
232 
233 #else /* !_KERNEL */
234 
235 #include <sys/cdefs.h>
236 
237 __BEGIN_DECLS
238 void	moncontrol(int);
239 void	monstartup(u_long, u_long);
240 __END_DECLS
241 
242 #endif /* _KERNEL */
243 
244 #endif /* !_SYS_GMON_H_ */
245