1 files changed, 116 insertions, 0 deletions
diff --git a/netwerk/test/TestWriteSpeed.cpp b/netwerk/test/TestWriteSpeed.cpp
new file mode 100644
index 000000000..0b0260fdd
--- /dev/null
+++ b/netwerk/test/TestWriteSpeed.cpp
@@ -0,0 +1,116 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "prio.h"
+#include "prinrval.h"
+#include "prmem.h"
+#include <stdio.h>
+#include <math.h>
+
+void 
+NS_MeanAndStdDev(double n, double sumOfValues, double sumOfSquaredValues,
+                 double *meanResult, double *stdDevResult)
+{
+  double mean = 0.0, var = 0.0, stdDev = 0.0;
+  if (n > 0.0 && sumOfValues >= 0) {
+    mean = sumOfValues / n;
+    double temp = (n * sumOfSquaredValues) - (sumOfValues * sumOfValues);
+    if (temp < 0.0 || n <= 1)
+      var = 0.0;
+    else
+      var = temp / (n * (n - 1));
+    // for some reason, Windows says sqrt(0.0) is "-1.#J" (?!) so do this:
+    stdDev = var != 0.0 ? sqrt(var) : 0.0;
+  }
+  *meanResult = mean;
+  *stdDevResult = stdDev;
+}
+
+int
+Test(const char* filename, int32_t minSize, int32_t maxSize, 
+     int32_t sizeIncrement, int32_t iterations)
+{
+    fprintf(stdout, "      size  write:    mean     stddev      iters  total:    mean     stddev      iters\n");
+    for (int32_t size = minSize; size <= maxSize; size += sizeIncrement) {
+        // create a buffer of stuff to write
+        char* buf = (char*)PR_Malloc(size);
+        if (buf == nullptr)
+            return -1;
+
+        // initialize it with a pattern
+        int32_t i;
+        char hex[] = "0123456789ABCDEF";
+        for (i = 0; i < size; i++) {
+            buf[i] = hex[i & 0xF];
+        }
+
+        double writeCount = 0, writeRate = 0, writeRateSquared = 0;
+        double totalCount = 0, totalRate = 0, totalRateSquared = 0;
+        for (i = 0; i < iterations; i++) {
+            PRIntervalTime start = PR_IntervalNow();
+
+            char name[1024];
+            sprintf(name, "%s_%d", filename, i);
+            PRFileDesc* fd = PR_Open(name, PR_WRONLY | PR_CREATE_FILE | PR_TRUNCATE, 0664);
+            if (fd == nullptr)
+                return -1;
+
+            PRIntervalTime writeStart = PR_IntervalNow();
+            int32_t rv = PR_Write(fd, buf, size);
+            if (rv < 0) return rv;
+            if (rv != size) return -1;
+            PRIntervalTime writeStop = PR_IntervalNow();
+
+            PRStatus st = PR_Close(fd);
+            if (st == PR_FAILURE) return -1; 
+
+            PRIntervalTime stop = PR_IntervalNow();
+
+            PRIntervalTime writeTime = PR_IntervalToMilliseconds(writeStop - writeStart);
+            if (writeTime > 0) {
+                double wr = size / writeTime;
+                writeRate += wr;
+                writeRateSquared += wr * wr;
+                writeCount++;
+            }
+
+            PRIntervalTime totalTime = PR_IntervalToMilliseconds(stop - start);
+            if (totalTime > 0) {
+                double t = size / totalTime;
+                totalRate += t;
+                totalRateSquared += t * t;
+                totalCount++;
+            }
+        }
+
+        PR_Free(buf);
+
+        double writeMean, writeStddev;
+        double totalMean, totalStddev;
+        NS_MeanAndStdDev(writeCount, writeRate, writeRateSquared,
+                         &writeMean, &writeStddev);
+        NS_MeanAndStdDev(totalCount, totalRate, totalRateSquared,
+                         &totalMean, &totalStddev);
+        fprintf(stdout, "%10d      %10.2f %10.2f %10d      %10.2f %10.2f %10d\n",
+                size, writeMean, writeStddev, (int32_t)writeCount, 
+                totalMean, totalStddev, (int32_t)totalCount);
+    }
+    return 0;
+}
+
+int
+main(int argc, char* argv[])
+{
+    if (argc != 5) {
+        printf("usage: %s <min buf size (K)> <max buf size (K)> <size increment (K)> <iterations>\n", argv[0]);
+        return -1;
+    }
+    Test("y:\\foo",
+         atoi(argv[1]) * 1024,
+         atoi(argv[2]) * 1024,
+         atoi(argv[3]) * 1024,
+         atoi(argv[4]));
+    return 0;
+}