The Tor Browser: netwerk/test/TestWriteSpeed.cpp@ca08bd8f51b2

     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/. */

     6 #include "prio.h"

     7 #include "prinrval.h"

     8 #include "prmem.h"

     9 #include <stdio.h>

    10 #include <math.h>

    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 }

    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;

    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         }

    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();

    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;

    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();

    66             PRStatus st = PR_Close(fd);

    67             if (st == PR_FAILURE) return -1;

    69             PRIntervalTime stop = PR_IntervalNow();

    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             }

    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         }

    88         PR_Free(buf);

    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 }

   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 }

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