Handle negative run lengths in wfu/mtbf calculations

This commit is contained in:
Nick Mathewson 2010-11-22 12:39:22 -05:00
parent bea0a31c1c
commit 5a9903b9e0
2 changed files with 19 additions and 6 deletions

View File

@ -4,4 +4,9 @@
treat it as having any downtime for the purposes of stability
calculation, whereas clients would experience downtime since the
IP could take a while to propagate to them. Resolves issue 1035.
o Minor bugfixes (authorities)
- Try to be more robust to hops back in time when calculating
router stability. Previously, if a run of uptime or downtime
appeared to be negative, the calculation could give incorrect
results. Bugfix on 0.2.0.6-alpha.

View File

@ -380,12 +380,20 @@ rep_hist_note_router_unreachable(const char *id, time_t when)
long run_length = when - hist->start_of_run;
format_local_iso_time(tbuf, hist->start_of_run);
hist->weighted_run_length += run_length;
hist->total_run_weights += 1.0;
hist->start_of_run = 0;
hist->weighted_uptime += run_length;
hist->total_weighted_time += run_length;
if (run_length < 0) {
unsigned long penalty = -run_length;
#define SUBTRACT_CLAMPED(var, penalty) \
do { (var) = (var) < (penalty) ? 0 : (var) - (penalty); } while (0)
SUBTRACT_CLAMPED(hist->weighted_run_length, penalty);
SUBTRACT_CLAMPED(hist->weighted_uptime, penalty);
} else {
hist->weighted_run_length += run_length;
hist->weighted_uptime += run_length;
hist->total_weighted_time += run_length;
}
was_running = 1;
log_info(LD_HIST, "Router %s is now non-Running: it had previously been "
"Running since %s. Its total weighted uptime is %lu/%lu.",
@ -458,7 +466,7 @@ rep_hist_downrate_old_runs(time_t now)
static double
get_stability(or_history_t *hist, time_t when)
{
unsigned long total = hist->weighted_run_length;
long total = hist->weighted_run_length;
double total_weights = hist->total_run_weights;
if (hist->start_of_run) {
@ -494,8 +502,8 @@ get_total_weighted_time(or_history_t *hist, time_t when)
static double
get_weighted_fractional_uptime(or_history_t *hist, time_t when)
{
unsigned long total = hist->total_weighted_time;
unsigned long up = hist->weighted_uptime;
long total = hist->total_weighted_time;
long up = hist->weighted_uptime;
if (hist->start_of_run) {
long run_length = (when - hist->start_of_run);