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
  33 /* Makes coverage_run run every 5000 ms (5 seconds).
  34  * If this value is redefined, the new value must
  35  * divide 60000 (1 minute). */
  36 #define COVERAGE_RUN_INTERVAL    5000
  37 BUILD_ASSERT_DECL(60000 % COVERAGE_RUN_INTERVAL == 0);
  38
  39 /* Defines the moving average array length. */
  40 #define MIN_AVG_LEN (60000/COVERAGE_RUN_INTERVAL)
  41 #define HR_AVG_LEN  60
  42
  43 /* A coverage counter. */
  44 struct coverage_counter {
  45     const char *const name;            /* Textual name. */
  46     unsigned int (*const count)(void); /* Gets, zeros this thread's count. */
  47     unsigned long long int total;      /* Total count. */
  48     unsigned long long int last_total;
  49     /* The moving average arrays. */
  50     unsigned int min[MIN_AVG_LEN];
  51     unsigned int hr[HR_AVG_LEN];
  52 };
  53
  54 /* Defines COUNTER.  There must be exactly one such definition at file scope
  55  * within a program. */
  56 #if USE_LINKER_SECTIONS
  57 #define COVERAGE_DEFINE(COUNTER)                                        \
  58         DEFINE_STATIC_PER_THREAD_DATA(unsigned int,                     \
  59                                       counter_##COUNTER, 0);            \
  60         static unsigned int COUNTER##_count(void)                       \
  61         {                                                               \
  62             unsigned int *countp = counter_##COUNTER##_get();           \
  63             unsigned int count = *countp;                               \
  64             *countp = 0;                                                \
  65             return count;                                               \
  66         }                                                               \
  67         static inline void COUNTER##_add(unsigned int n)                \
  68         {                                                               \
  69             *counter_##COUNTER##_get() += n;                            \
  70         }                                                               \
  71         extern struct coverage_counter counter_##COUNTER;               \
  72         struct coverage_counter counter_##COUNTER                       \
  73             = { #COUNTER, COUNTER##_count, 0, 0, {0}, {0} };            \
  74         extern struct coverage_counter *counter_ptr_##COUNTER;          \
  75         struct coverage_counter *counter_ptr_##COUNTER                  \
  76             __attribute__((section("coverage"))) = &counter_##COUNTER
  77 #else
  78 #define COVERAGE_DEFINE(COUNTER)                                        \
  79         DECLARE_EXTERN_PER_THREAD_DATA(unsigned int,                    \
  80                                        counter_##COUNTER);              \
  81         static inline void COUNTER##_add(unsigned int n)                \
  82         {                                                               \
  83             *counter_##COUNTER##_get() += n;                            \
  84         }                                                               \
  85         extern struct coverage_counter counter_##COUNTER
  86 #endif
  87
  88 /* Adds 1 to COUNTER. */
  89 #define COVERAGE_INC(COUNTER) COVERAGE_ADD(COUNTER, 1)
  90
  91 /* Adds AMOUNT to COUNTER. */
  92 #define COVERAGE_ADD(COUNTER, AMOUNT) COUNTER##_add(AMOUNT)
  93
  94 void coverage_init(void);
  95 void coverage_log(void);
  96 void coverage_clear(void);
  97 void coverage_run(void);
  98
  99 /* Implementation detail. */
 100 #define COVERAGE_DEFINE__(COUNTER)                              \
 101
 102 #endif /* coverage.h */