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Remove a source of error during path bias scaling

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If any circuits were opened during a scaling event, we were scaling attempts
and successes by different amounts. This leads to rounding error.

The fix is to record how many circuits are in a state that hasn't been fully
counted yet, and subtract that before scaling, and add it back afterwords.
This commit is contained in:
Mike Perry 2013-01-18 20:17:23 -08:00
parent a2db17a1aa
commit d80b881a52
1 changed files with 58 additions and 54 deletions
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112
src/or/circuitbuild.c
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@ -2071,55 +2071,14 @@ pathbias_count_timeout(origin_circuit_t *circ)
}
/**
* Return the number of circuits counted as successfully closed for
* this guard.
*
* Also add in the currently open circuits to give them the benefit
* of the doubt.
* Helper function to count all of the currently opened circuits
* for a guard that are in a given path state range. The state
* range is inclusive on both ends.
*/
double
pathbias_get_close_success_count(entry_guard_t *guard)
{
circuit_t *circ;
int open_circuits = 0;
/* Count currently open circuits. Give them the benefit of the doubt. */
for (circ = global_circuitlist; circ; circ = circ->next) {
origin_circuit_t *ocirc = NULL;
if (!CIRCUIT_IS_ORIGIN(circ) || /* didn't originate here */
circ->marked_for_close) /* already counted */
continue;
ocirc = TO_ORIGIN_CIRCUIT(circ);
if (!ocirc->cpath || !ocirc->cpath->extend_info)
continue;
/* Don't count known failed or already counted circuits */
if (ocirc->path_state >= PATH_STATE_USE_FAILED)
continue;
if (ocirc->path_state >= PATH_STATE_BUILD_SUCCEEDED &&
pathbias_should_count(ocirc) &&
fast_memeq(guard->identity,
ocirc->cpath->extend_info->identity_digest,
DIGEST_LEN)) {
open_circuits++;
}
}
return guard->successful_circuits_closed + open_circuits;
}
/**
* Return the number of circuits counted as successfully used
* this guard.
*
* Also add in the currently open circuits that we are attempting
* to use to give them the benefit of the doubt.
*/
double
pathbias_get_use_success_count(entry_guard_t *guard)
static int
pathbias_count_circs_in_states(entry_guard_t *guard,
path_state_t from,
path_state_t to)
{
circuit_t *circ = global_circuitlist;
int open_circuits = 0;
@ -2136,11 +2095,8 @@ pathbias_get_use_success_count(entry_guard_t *guard)
if (!ocirc->cpath || !ocirc->cpath->extend_info)
continue;
/* Don't count known failed or already counted circuits */
if (ocirc->path_state >= PATH_STATE_USE_FAILED)
continue;
if (ocirc->path_state >= PATH_STATE_USE_ATTEMPTED &&
if (ocirc->path_state >= from &&
ocirc->path_state <= to &&
pathbias_should_count(ocirc) &&
fast_memeq(guard->identity,
ocirc->cpath->extend_info->identity_digest,
@ -2149,7 +2105,39 @@ pathbias_get_use_success_count(entry_guard_t *guard)
}
}
return guard->use_successes + open_circuits;
return open_circuits;
}
/**
* Return the number of circuits counted as successfully closed for
* this guard.
*
* Also add in the currently open circuits to give them the benefit
* of the doubt.
*/
double
pathbias_get_close_success_count(entry_guard_t *guard)
{
return guard->successful_circuits_closed +
pathbias_count_circs_in_states(guard,
PATH_STATE_BUILD_SUCCEEDED,
PATH_STATE_USE_SUCCEEDED);
}
/**
* Return the number of circuits counted as successfully used
* this guard.
*
* Also add in the currently open circuits that we are attempting
* to use to give them the benefit of the doubt.
*/
double
pathbias_get_use_success_count(entry_guard_t *guard)
{
return guard->use_successes +
pathbias_count_circs_in_states(guard,
PATH_STATE_USE_ATTEMPTED,
PATH_STATE_USE_SUCCEEDED);
}
/**
@ -2252,6 +2240,10 @@ pathbias_check_use_rate(entry_guard_t *guard)
if (guard->use_attempts > pathbias_get_scale_use_threshold(options)) {
const int scale_factor = pathbias_get_scale_factor(options);
const int mult_factor = pathbias_get_mult_factor(options);
int opened_attempts = pathbias_count_circs_in_states(guard,
PATH_STATE_USE_ATTEMPTED, PATH_STATE_USE_ATTEMPTED);
guard->use_attempts -= opened_attempts;
log_info(LD_CIRC,
"Scaling pathbias use counts to (%f/%f)*(%d/%d) for guard %s=%s",
guard->use_successes, guard->use_attempts,
@ -2263,6 +2255,8 @@ pathbias_check_use_rate(entry_guard_t *guard)
guard->use_attempts /= scale_factor;
guard->use_successes /= scale_factor;
guard->use_attempts += opened_attempts;
}
return 0;
@ -2393,6 +2387,13 @@ pathbias_check_close_rate(entry_guard_t *guard)
if (guard->circ_attempts > pathbias_get_scale_threshold(options)) {
const int scale_factor = pathbias_get_scale_factor(options);
const int mult_factor = pathbias_get_mult_factor(options);
int opened_attempts = pathbias_count_circs_in_states(guard,
PATH_STATE_BUILD_ATTEMPTED, PATH_STATE_BUILD_ATTEMPTED);
int opened_built = pathbias_count_circs_in_states(guard,
PATH_STATE_BUILD_SUCCEEDED,
PATH_STATE_USE_FAILED);
guard->circ_attempts -= opened_attempts;
guard->circ_successes -= opened_built;
log_info(LD_CIRC,
"Scaling pathbias counts to (%f/%f)*(%d/%d) for guard %s=%s",
guard->circ_successes, guard->circ_attempts,
@ -2412,6 +2413,9 @@ pathbias_check_close_rate(entry_guard_t *guard)
guard->successful_circuits_closed /= scale_factor;
guard->collapsed_circuits /= scale_factor;
guard->unusable_circuits /= scale_factor;
guard->circ_attempts += opened_attempts;
guard->circ_successes += opened_built;
}
return 0;