Security-57031.1.35.tar.gz

[apple/security.git] / SecurityTests / cspxutils / utilLib / cputime.c

diff --git a/SecurityTests/cspxutils/utilLib/cputime.c b/SecurityTests/cspxutils/utilLib/cputime.c
new file mode 100644 (file)
index 0000000..0238f04
--- /dev/null
+++ b/SecurityTests/cspxutils/utilLib/cputime.c
@@ -0,0 +1,81 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <libc.h>
+#include "cputime.h"
+
+/* 
+ * This returns the frequency of the TBR in cycles per second.
+ */
+static double GetTBRFreq(void) {
+       mach_timebase_info_data_t tinfo;
+       mach_timebase_info(&tinfo);
+       
+       double machRatio = (double)tinfo.numer / (double)tinfo.denom;
+       return machRatio;
+}
+
+/*
+ * Return TBR Frequency, getting it lazily once. May not be thread safe.
+ */
+static double TbrFreqLocal = 0.0;              // ration for NANOSECONDS
+static double tbrFreq()
+{
+       if(TbrFreqLocal == 0.0) {
+               TbrFreqLocal = GetTBRFreq();
+               printf("machRatio %e\n", TbrFreqLocal);
+       }
+       return TbrFreqLocal;
+}
+
+// seconds
+double CPUTimeDeltaSec(CPUTime from, CPUTime to)       
+{
+       CPUTime delta = to - from;
+       return (double)delta * (tbrFreq() * (double)1e-9);
+}
+
+// milliseconds
+double CPUTimeDeltaMs(CPUTime from, CPUTime to)
+{
+       CPUTime delta = to - from;
+       return (double)delta * (tbrFreq() * (double)1e-6);
+}
+
+// microseconds
+double CPUTimeDeltaUs(CPUTime from, CPUTime to)
+{
+       CPUTime delta = to - from;
+       return (double)delta * (tbrFreq() * (double)1e-3);
+}
+       
+/*
+ * Calculate the average of an array of doubles. The lowest and highest values
+ * are discarded if there are more than two samples. Typically used to get an
+ * average of a set of values returned from CPUTimeDelta*().
+ */
+double CPUTimeAvg(
+       const double *array,
+       unsigned arraySize)
+{
+       double sum = 0;
+       double lowest = array[0];
+       double highest = array[0];
+       
+       for(unsigned dex=0; dex<arraySize; dex++) {
+               double curr = array[dex];
+               sum += curr;
+               if(curr < lowest) {
+                       lowest = curr;
+               }
+               if(curr > highest) {
+                       highest = curr;
+               }
+       }
+       if(arraySize > 2) {
+               sum -= lowest;
+               sum -= highest;
+               arraySize -= 2;
+       }
+       return sum / (double)arraySize;
+}