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issue: 4043235 TCP_USER_TIMER wrong RTO behavior #297

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issue: 4043235 TCP_USER_TIMER wrong RTO behavior #297

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54 changes: 1 addition & 53 deletions src/utils/rdtsc.h
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Original file line number Diff line number Diff line change
Expand Up @@ -100,61 +100,9 @@ static bool get_cpu_hz(double &hz_min, double &hz_max)
return true;
}

/**
* Calibrate TSC with CPU speed
* @return number of tsc ticks per second
*/
static inline tscval_t get_tsc_rate_per_second()
{
static tscval_t tsc_per_second = TSCVAL_INITIALIZER;
if (!tsc_per_second) {
double hz_min = -1, hz_max = -1;
if (get_cpu_hz(hz_min, hz_max)) {
tsc_per_second = (tscval_t)hz_max;
} else {
// failure calibrating TSC to CPU speed
tsc_per_second = 2 * 1e6; // assume 2 MHz CPU speed
}
}
return tsc_per_second;
}

/**
* 'gettimeofday()' based on RDTSC
* Re-sync with system clock no more then once a second
*/
inline int gettimefromtsc(struct timespec *ts)
{
static tscval_t tsc_start = TSCVAL_INITIALIZER;
static struct timespec ts_start = TIMESPEC_INITIALIZER;

struct timespec ts_delta = TIMESPEC_INITIALIZER;
tscval_t tsc_now, tsc_delta;
uint64_t nsec_delta = 0;

if (!ts_isset(&ts_start)) {
clock_gettime(CLOCK_MONOTONIC, &ts_start);
gettimeoftsc(&tsc_start);
}
gettimeoftsc(&tsc_now);
tsc_delta = tsc_now - tsc_start;
nsec_delta = tsc_delta * NSEC_PER_SEC / get_tsc_rate_per_second();

ts_delta.tv_sec = nsec_delta / NSEC_PER_SEC;
ts_delta.tv_nsec = nsec_delta - ts_delta.tv_sec * NSEC_PER_SEC;
ts_add(&ts_start, &ts_delta, ts);

// Once a second re-sync our start time with real time-of-day
if (tsc_delta > get_tsc_rate_per_second()) {
ts_clear(&ts_start);
}

return 0;
}

static inline int gettime(struct timespec *ts)
{
return gettimefromtsc(ts);
return clock_gettime(CLOCK_MONOTONIC, ts);
}

static inline int gettime(struct timeval *tv)
Expand Down