michael@0: /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #include "prio.h"
michael@0: #include "prinrval.h"
michael@0: #include "prmem.h"
michael@0: #include <stdio.h>
michael@0: #include <math.h>
michael@0: 
michael@0: void 
michael@0: NS_MeanAndStdDev(double n, double sumOfValues, double sumOfSquaredValues,
michael@0:                  double *meanResult, double *stdDevResult)
michael@0: {
michael@0:   double mean = 0.0, var = 0.0, stdDev = 0.0;
michael@0:   if (n > 0.0 && sumOfValues >= 0) {
michael@0:     mean = sumOfValues / n;
michael@0:     double temp = (n * sumOfSquaredValues) - (sumOfValues * sumOfValues);
michael@0:     if (temp < 0.0 || n <= 1)
michael@0:       var = 0.0;
michael@0:     else
michael@0:       var = temp / (n * (n - 1));
michael@0:     // for some reason, Windows says sqrt(0.0) is "-1.#J" (?!) so do this:
michael@0:     stdDev = var != 0.0 ? sqrt(var) : 0.0;
michael@0:   }
michael@0:   *meanResult = mean;
michael@0:   *stdDevResult = stdDev;
michael@0: }
michael@0: 
michael@0: int
michael@0: Test(const char* filename, int32_t minSize, int32_t maxSize, 
michael@0:      int32_t sizeIncrement, int32_t iterations)
michael@0: {
michael@0:     fprintf(stdout, "      size  write:    mean     stddev      iters  total:    mean     stddev      iters\n");
michael@0:     for (int32_t size = minSize; size <= maxSize; size += sizeIncrement) {
michael@0:         // create a buffer of stuff to write
michael@0:         char* buf = (char*)PR_Malloc(size);
michael@0:         if (buf == nullptr)
michael@0:             return -1;
michael@0: 
michael@0:         // initialize it with a pattern
michael@0:         int32_t i;
michael@0:         char hex[] = "0123456789ABCDEF";
michael@0:         for (i = 0; i < size; i++) {
michael@0:             buf[i] = hex[i & 0xF];
michael@0:         }
michael@0: 
michael@0:         double writeCount = 0, writeRate = 0, writeRateSquared = 0;
michael@0:         double totalCount = 0, totalRate = 0, totalRateSquared = 0;
michael@0:         for (i = 0; i < iterations; i++) {
michael@0:             PRIntervalTime start = PR_IntervalNow();
michael@0: 
michael@0:             char name[1024];
michael@0:             sprintf(name, "%s_%d", filename, i);
michael@0:             PRFileDesc* fd = PR_Open(name, PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0664);
michael@0:             if (fd == nullptr)
michael@0:                 return -1;
michael@0: 
michael@0:             PRIntervalTime writeStart = PR_IntervalNow();
michael@0:             int32_t rv = PR_Write(fd, buf, size);
michael@0:             if (rv < 0) return rv;
michael@0:             if (rv != size) return -1;
michael@0:             PRIntervalTime writeStop = PR_IntervalNow();
michael@0: 
michael@0:             PRStatus st = PR_Close(fd);
michael@0:             if (st == PR_FAILURE) return -1; 
michael@0: 
michael@0:             PRIntervalTime stop = PR_IntervalNow();
michael@0: 
michael@0:             PRIntervalTime writeTime = PR_IntervalToMilliseconds(writeStop - writeStart);
michael@0:             if (writeTime > 0) {
michael@0:                 double wr = size / writeTime;
michael@0:                 writeRate += wr;
michael@0:                 writeRateSquared += wr * wr;
michael@0:                 writeCount++;
michael@0:             }
michael@0: 
michael@0:             PRIntervalTime totalTime = PR_IntervalToMilliseconds(stop - start);
michael@0:             if (totalTime > 0) {
michael@0:                 double t = size / totalTime;
michael@0:                 totalRate += t;
michael@0:                 totalRateSquared += t * t;
michael@0:                 totalCount++;
michael@0:             }
michael@0:         }
michael@0: 
michael@0:         PR_Free(buf);
michael@0: 
michael@0:         double writeMean, writeStddev;
michael@0:         double totalMean, totalStddev;
michael@0:         NS_MeanAndStdDev(writeCount, writeRate, writeRateSquared,
michael@0:                          &writeMean, &writeStddev);
michael@0:         NS_MeanAndStdDev(totalCount, totalRate, totalRateSquared,
michael@0:                          &totalMean, &totalStddev);
michael@0:         fprintf(stdout, "%10d      %10.2f %10.2f %10d      %10.2f %10.2f %10d\n",
michael@0:                 size, writeMean, writeStddev, (int32_t)writeCount, 
michael@0:                 totalMean, totalStddev, (int32_t)totalCount);
michael@0:     }
michael@0:     return 0;
michael@0: }
michael@0: 
michael@0: int
michael@0: main(int argc, char* argv[])
michael@0: {
michael@0:     if (argc != 5) {
michael@0:         printf("usage: %s <min buf size (K)> <max buf size (K)> <size increment (K)> <iterations>\n", argv[0]);
michael@0:         return -1;
michael@0:     }
michael@0:     Test("y:\\foo",
michael@0:          atoi(argv[1]) * 1024,
michael@0:          atoi(argv[2]) * 1024,
michael@0:          atoi(argv[3]) * 1024,
michael@0:          atoi(argv[4]));
michael@0:     return 0;
michael@0: }