ceph/src/zstd/programs/benchfn.h

   1 /*
   2  * Copyright (c) 2016-2020, Yann Collet, Facebook, Inc.
   3  * All rights reserved.
   4  *
   5  * This source code is licensed under both the BSD-style license (found in the
   6  * LICENSE file in the root directory of this source tree) and the GPLv2 (found
   7  * in the COPYING file in the root directory of this source tree).
   8  * You may select, at your option, one of the above-listed licenses.
   9  */
  10
  11
  12 /* benchfn :
  13  * benchmark any function on a set of input
  14  * providing result in nanoSecPerRun
  15  * or detecting and returning an error
  16  */
  17
  18 #if defined (__cplusplus)
  19 extern "C" {
  20 #endif
  21
  22 #ifndef BENCH_FN_H_23876
  23 #define BENCH_FN_H_23876
  24
  25 /* ===  Dependencies  === */
  26 #include <stddef.h>   /* size_t */
  27
  28
  29 /* ====  Benchmark any function, iterated on a set of blocks  ==== */
  30
  31 /* BMK_runTime_t: valid result return type */
  32
  33 typedef struct {
  34     double nanoSecPerRun;  /* time per iteration (over all blocks) */
  35     size_t sumOfReturn;         /* sum of return values */
  36 } BMK_runTime_t;
  37
  38
  39 /* BMK_runOutcome_t:
  40  * type expressing the outcome of a benchmark run by BMK_benchFunction(),
  41  * which can be either valid or invalid.
  42  * benchmark outcome can be invalid if errorFn is provided.
  43  * BMK_runOutcome_t must be considered "opaque" : never access its members directly.
  44  * Instead, use its assigned methods :
  45  * BMK_isSuccessful_runOutcome, BMK_extract_runTime, BMK_extract_errorResult.
  46  * The structure is only described here to allow its allocation on stack. */
  47
  48 typedef struct {
  49     BMK_runTime_t internal_never_ever_use_directly;
  50     size_t error_result_never_ever_use_directly;
  51     int error_tag_never_ever_use_directly;
  52 } BMK_runOutcome_t;
  53
  54
  55 /* prototypes for benchmarked functions */
  56 typedef size_t (*BMK_benchFn_t)(const void* src, size_t srcSize, void* dst, size_t dstCapacity, void* customPayload);
  57 typedef size_t (*BMK_initFn_t)(void* initPayload);
  58 typedef unsigned (*BMK_errorFn_t)(size_t);
  59
  60
  61 /* BMK_benchFunction() parameters are provided via the following structure.
  62  * A structure is preferable for readability,
  63  * as the number of parameters required is fairly large.
  64  * No initializer is provided, because it doesn't make sense to provide some "default" :
  65  * all parameters must be specified by the caller.
  66  * optional parameters are labelled explicitly, and accept value NULL when not used */
  67 typedef struct {
  68     BMK_benchFn_t benchFn;    /* the function to benchmark, over the set of blocks */
  69     void* benchPayload;       /* pass custom parameters to benchFn  :
  70                                * (*benchFn)(srcBuffers[i], srcSizes[i], dstBuffers[i], dstCapacities[i], benchPayload) */
  71     BMK_initFn_t initFn;      /* (*initFn)(initPayload) is run once per run, at the beginning. */
  72     void* initPayload;        /* Both arguments can be NULL, in which case nothing is run. */
  73     BMK_errorFn_t errorFn;    /* errorFn will check each return value of benchFn over each block, to determine if it failed or not.
  74                                * errorFn can be NULL, in which case no check is performed.
  75                                * errorFn must return 0 when benchFn was successful, and >= 1 if it detects an error.
  76                                * Execution is stopped as soon as an error is detected.
  77                                * the triggering return value can be retrieved using BMK_extract_errorResult(). */
  78     size_t blockCount;        /* number of blocks to operate benchFn on.
  79                                * It's also the size of all array parameters :
  80                                * srcBuffers, srcSizes, dstBuffers, dstCapacities, blockResults */
  81     const void *const * srcBuffers; /* read-only array of buffers to be operated on by benchFn */
  82     const size_t* srcSizes;   /* read-only array containing sizes of srcBuffers */
  83     void *const * dstBuffers; /* array of buffers to be written into by benchFn. This array is not optional, it must be provided even if unused by benchfn. */
  84     const size_t* dstCapacities; /* read-only array containing capacities of dstBuffers. This array must be present. */
  85     size_t* blockResults;     /* Optional: store the return value of benchFn for each block. Use NULL if this result is not requested. */
  86 } BMK_benchParams_t;
  87
  88
  89 /* BMK_benchFunction() :
  90  * This function benchmarks benchFn and initFn, providing a result.
  91  *
  92  * params : see description of BMK_benchParams_t above.
  93  * nbLoops: defines number of times benchFn is run over the full set of blocks.
  94  *          Minimum value is 1. A 0 is interpreted as a 1.
  95  *
  96  * @return: can express either an error or a successful result.
  97  *          Use BMK_isSuccessful_runOutcome() to check if benchmark was successful.
  98  *          If yes, extract the result with BMK_extract_runTime(),
  99  *          it will contain :
 100  *              .sumOfReturn : the sum of all return values of benchFn through all of blocks
 101  *              .nanoSecPerRun : time per run of benchFn + (time for initFn / nbLoops)
 102  *          .sumOfReturn is generally intended for functions which return a # of bytes written into dstBuffer,
 103  *              in which case, this value will be the total amount of bytes written into dstBuffer.
 104  *
 105  * blockResults : when provided (!= NULL), and when benchmark is successful,
 106  *                params.blockResults contains all return values of `benchFn` over all blocks.
 107  *                when provided (!= NULL), and when benchmark failed,
 108  *                params.blockResults contains return values of `benchFn` over all blocks preceding and including the failed block.
 109  */
 110 BMK_runOutcome_t BMK_benchFunction(BMK_benchParams_t params, unsigned nbLoops);
 111
 112
 113
 114 /* check first if the benchmark was successful or not */
 115 int BMK_isSuccessful_runOutcome(BMK_runOutcome_t outcome);
 116
 117 /* If the benchmark was successful, extract the result.
 118  * note : this function will abort() program execution if benchmark failed !
 119  *        always check if benchmark was successful first !
 120  */
 121 BMK_runTime_t BMK_extract_runTime(BMK_runOutcome_t outcome);
 122
 123 /* when benchmark failed, it means one invocation of `benchFn` failed.
 124  * The failure was detected by `errorFn`, operating on return values of `benchFn`.
 125  * Returns the faulty return value.
 126  * note : this function will abort() program execution if benchmark did not failed.
 127  *        always check if benchmark failed first !
 128  */
 129 size_t BMK_extract_errorResult(BMK_runOutcome_t outcome);
 130
 131
 132
 133 /* ====  Benchmark any function, returning intermediate results  ==== */
 134
 135 /* state information tracking benchmark session */
 136 typedef struct BMK_timedFnState_s BMK_timedFnState_t;
 137
 138 /* BMK_benchTimedFn() :
 139  * Similar to BMK_benchFunction(), most arguments being identical.
 140  * Automatically determines `nbLoops` so that each result is regularly produced at interval of about run_ms.
 141  * Note : minimum `nbLoops` is 1, therefore a run may last more than run_ms, and possibly even more than total_ms.
 142  * Usage - initialize timedFnState, select benchmark duration (total_ms) and each measurement duration (run_ms)
 143  *         call BMK_benchTimedFn() repetitively, each measurement is supposed to last about run_ms
 144  *         Check if total time budget is spent or exceeded, using BMK_isCompleted_TimedFn()
 145  */
 146 BMK_runOutcome_t BMK_benchTimedFn(BMK_timedFnState_t* timedFnState,
 147                                   BMK_benchParams_t params);
 148
 149 /* Tells if duration of all benchmark runs has exceeded total_ms
 150  */
 151 int BMK_isCompleted_TimedFn(const BMK_timedFnState_t* timedFnState);
 152
 153 /* BMK_createTimedFnState() and BMK_resetTimedFnState() :
 154  * Create/Set BMK_timedFnState_t for next benchmark session,
 155  * which shall last a minimum of total_ms milliseconds,
 156  * producing intermediate results, paced at interval of (approximately) run_ms.
 157  */
 158 BMK_timedFnState_t* BMK_createTimedFnState(unsigned total_ms, unsigned run_ms);
 159 void BMK_resetTimedFnState(BMK_timedFnState_t* timedFnState, unsigned total_ms, unsigned run_ms);
 160 void BMK_freeTimedFnState(BMK_timedFnState_t* state);
 161
 162
 163 /* BMK_timedFnState_shell and BMK_initStatic_timedFnState() :
 164  * Makes it possible to statically allocate a BMK_timedFnState_t on stack.
 165  * BMK_timedFnState_shell is only there to allocate space,
 166  * never ever access its members.
 167  * BMK_timedFnState_t() actually accepts any buffer.
 168  * It will check if provided buffer is large enough and is correctly aligned,
 169  * and will return NULL if conditions are not respected.
 170  */
 171 #define BMK_TIMEDFNSTATE_SIZE 64
 172 typedef union {
 173     char never_access_space[BMK_TIMEDFNSTATE_SIZE];
 174     long long alignment_enforcer;  /* must be aligned on 8-bytes boundaries */
 175 } BMK_timedFnState_shell;
 176 BMK_timedFnState_t* BMK_initStatic_timedFnState(void* buffer, size_t size, unsigned total_ms, unsigned run_ms);
 177
 178
 179 #endif   /* BENCH_FN_H_23876 */
 180
 181 #if defined (__cplusplus)
 182 }
 183 #endif