netwerk/test/TestWriteSpeed.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /* This Source Code Form is subject to the terms of the Mozilla Public
   3  * License, v. 2.0. If a copy of the MPL was not distributed with this
   4  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   5
   6 #include "prio.h"
   7 #include "prinrval.h"
   8 #include "prmem.h"
   9 #include <stdio.h>
  10 #include <math.h>
  11
  12 void
  13 NS_MeanAndStdDev(double n, double sumOfValues, double sumOfSquaredValues,
  14                  double *meanResult, double *stdDevResult)
  15 {
  16   double mean = 0.0, var = 0.0, stdDev = 0.0;
  17   if (n > 0.0 && sumOfValues >= 0) {
  18     mean = sumOfValues / n;
  19     double temp = (n * sumOfSquaredValues) - (sumOfValues * sumOfValues);
  20     if (temp < 0.0 || n <= 1)
  21       var = 0.0;
  22     else
  23       var = temp / (n * (n - 1));
  24     // for some reason, Windows says sqrt(0.0) is "-1.#J" (?!) so do this:
  25     stdDev = var != 0.0 ? sqrt(var) : 0.0;
  26   }
  27   *meanResult = mean;
  28   *stdDevResult = stdDev;
  29 }
  30
  31 int
  32 Test(const char* filename, int32_t minSize, int32_t maxSize,
  33      int32_t sizeIncrement, int32_t iterations)
  34 {
  35     fprintf(stdout, "      size  write:    mean     stddev      iters  total:    mean     stddev      iters\n");
  36     for (int32_t size = minSize; size <= maxSize; size += sizeIncrement) {
  37         // create a buffer of stuff to write
  38         char* buf = (char*)PR_Malloc(size);
  39         if (buf == nullptr)
  40             return -1;
  41
  42         // initialize it with a pattern
  43         int32_t i;
  44         char hex[] = "0123456789ABCDEF";
  45         for (i = 0; i < size; i++) {
  46             buf[i] = hex[i & 0xF];
  47         }
  48
  49         double writeCount = 0, writeRate = 0, writeRateSquared = 0;
  50         double totalCount = 0, totalRate = 0, totalRateSquared = 0;
  51         for (i = 0; i < iterations; i++) {
  52             PRIntervalTime start = PR_IntervalNow();
  53
  54             char name[1024];
  55             sprintf(name, "%s_%d", filename, i);
  56             PRFileDesc* fd = PR_Open(name, PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0664);
  57             if (fd == nullptr)
  58                 return -1;
  59
  60             PRIntervalTime writeStart = PR_IntervalNow();
  61             int32_t rv = PR_Write(fd, buf, size);
  62             if (rv < 0) return rv;
  63             if (rv != size) return -1;
  64             PRIntervalTime writeStop = PR_IntervalNow();
  65
  66             PRStatus st = PR_Close(fd);
  67             if (st == PR_FAILURE) return -1;
  68
  69             PRIntervalTime stop = PR_IntervalNow();
  70
  71             PRIntervalTime writeTime = PR_IntervalToMilliseconds(writeStop - writeStart);
  72             if (writeTime > 0) {
  73                 double wr = size / writeTime;
  74                 writeRate += wr;
  75                 writeRateSquared += wr * wr;
  76                 writeCount++;
  77             }
  78
  79             PRIntervalTime totalTime = PR_IntervalToMilliseconds(stop - start);
  80             if (totalTime > 0) {
  81                 double t = size / totalTime;
  82                 totalRate += t;
  83                 totalRateSquared += t * t;
  84                 totalCount++;
  85             }
  86         }
  87
  88         PR_Free(buf);
  89
  90         double writeMean, writeStddev;
  91         double totalMean, totalStddev;
  92         NS_MeanAndStdDev(writeCount, writeRate, writeRateSquared,
  93                          &writeMean, &writeStddev);
  94         NS_MeanAndStdDev(totalCount, totalRate, totalRateSquared,
  95                          &totalMean, &totalStddev);
  96         fprintf(stdout, "%10d      %10.2f %10.2f %10d      %10.2f %10.2f %10d\n",
  97                 size, writeMean, writeStddev, (int32_t)writeCount,
  98                 totalMean, totalStddev, (int32_t)totalCount);
  99     }
 100     return 0;
 101 }
 102
 103 int
 104 main(int argc, char* argv[])
 105 {
 106     if (argc != 5) {
 107         printf("usage: %s <min buf size (K)> <max buf size (K)> <size increment (K)> <iterations>\n", argv[0]);
 108         return -1;
 109     }
 110     Test("y:\\foo",
 111          atoi(argv[1]) * 1024,
 112          atoi(argv[2]) * 1024,
 113          atoi(argv[3]) * 1024,
 114          atoi(argv[4]));
 115     return 0;
 116 }