This affects every kernel I tried, 4.9.[54|35|24], 3.18.27, RH 3.10.0-693*.
The test machine is a Dell R740 with 2X8168 and 384GB.
#include <time.h>
#include <stdio.h>
#include <sys/time.h>
inline long GetPerf()
{
int _hi, _lo;
__asm__ __volatile__ ("rdtsc":"=a" (_lo), "=d"(_hi));
return ((long) _hi << 32) | _lo;
}
int main()
{
struct timespec ts;
int i, count;
long start, end, delta, min, max, total, avg;
count = 100;
min = 0x7fffffff;
max = 0;
total = 0;
for (i = 0; i < count; i++)
{
start = GetPerf();
clock_gettime(CLOCK_REALTIME, &ts);
end = GetPerf();
delta = end - start;
if (delta > max) max = delta;
if (delta < min) min = delta;
total += delta;
}
avg = total / count;
printf("min: %ld\n", min);
--
//E. F. Berkley Shands, MSc
Senior Software Architect/Engineer
Exegy Systems Engineering//
**Exegy Inc.**
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Cell: (314) 303-2546
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