ofproto-provider: Update documentation.
[sliver-openvswitch.git] / lib / coverage.h
1 /*
2  * Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc.
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at:
7  *
8  *     http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16
17 #ifndef COVERAGE_H
18 #define COVERAGE_H 1
19
20 /* This file implements a simple form of coverage instrumentation.  Points in
21  * source code that are of interest must be explicitly annotated with
22  * COVERAGE_INC.  The coverage counters may be logged at any time with
23  * coverage_log().
24  *
25  * This form of coverage instrumentation is intended to be so lightweight that
26  * it can be enabled in production builds.  It is obviously not a substitute
27  * for traditional coverage instrumentation with e.g. "gcov", but it is still
28  * a useful debugging tool. */
29
30 #include "ovs-thread.h"
31 #include "vlog.h"
32 #include "compiler.h"
33
34 /* Makes coverage_run run every 5000 ms (5 seconds).
35  * If this value is redefined, the new value must
36  * divide 60000 (1 minute). */
37 #define COVERAGE_RUN_INTERVAL    5000
38 BUILD_ASSERT_DECL(60000 % COVERAGE_RUN_INTERVAL == 0);
39
40 #define COVERAGE_CLEAR_INTERVAL  1000
41 BUILD_ASSERT_DECL(COVERAGE_RUN_INTERVAL % COVERAGE_CLEAR_INTERVAL == 0);
42
43 /* Defines the moving average array length. */
44 #define MIN_AVG_LEN (60000/COVERAGE_RUN_INTERVAL)
45 #define HR_AVG_LEN  60
46
47 /* A coverage counter. */
48 struct coverage_counter {
49     const char *const name;            /* Textual name. */
50     unsigned int (*const count)(void); /* Gets, zeros this thread's count. */
51     unsigned long long int total;      /* Total count. */
52     unsigned long long int last_total;
53     /* The moving average arrays. */
54     unsigned int min[MIN_AVG_LEN];
55     unsigned int hr[HR_AVG_LEN];
56 };
57
58 void coverage_counter_register(struct coverage_counter*);
59
60 /* Defines COUNTER.  There must be exactly one such definition at file scope
61  * within a program. */
62 #define COVERAGE_DEFINE(COUNTER)                                        \
63         DEFINE_STATIC_PER_THREAD_DATA(unsigned int,                     \
64                                       counter_##COUNTER, 0);            \
65         static unsigned int COUNTER##_count(void)                       \
66         {                                                               \
67             unsigned int *countp = counter_##COUNTER##_get();           \
68             unsigned int count = *countp;                               \
69             *countp = 0;                                                \
70             return count;                                               \
71         }                                                               \
72         static inline void COUNTER##_add(unsigned int n)                \
73         {                                                               \
74             *counter_##COUNTER##_get() += n;                            \
75         }                                                               \
76         extern struct coverage_counter counter_##COUNTER;               \
77         struct coverage_counter counter_##COUNTER                       \
78             = { #COUNTER, COUNTER##_count, 0, 0, {0}, {0} };            \
79         OVS_CONSTRUCTOR(COUNTER##_init) {                               \
80             coverage_counter_register(&counter_##COUNTER);              \
81         }
82
83 /* Adds 1 to COUNTER. */
84 #define COVERAGE_INC(COUNTER) COVERAGE_ADD(COUNTER, 1)
85
86 /* Adds AMOUNT to COUNTER. */
87 #define COVERAGE_ADD(COUNTER, AMOUNT) COUNTER##_add(AMOUNT)
88
89 void coverage_init(void);
90 void coverage_log(void);
91 void coverage_clear(void);
92 void coverage_run(void);
93
94 /* Implementation detail. */
95 #define COVERAGE_DEFINE__(COUNTER)                              \
96
97 #endif /* coverage.h */