commit dfcfb5d17dcb89d51cdfe11ee89cb82791624ee3 Author: Mike Perry <mikeperry-git@fscked.org> Date: Wed Jan 30 18:40:46 2013 -0400 Refactor the scaling parameter fetching into a single function. Also, deprecate the torrc options for the scaling values. It's unlikely anyone but developers will ever tweak them, even if we provided a single ratio value. --- doc/tor.1.txt | 13 ++----- src/or/circuitbuild.c | 83 +++++++++++++++++++------------------------------ src/or/config.c | 4 +- src/or/or.h | 2 - 4 files changed, 38 insertions(+), 64 deletions(-) diff --git a/doc/tor.1.txt b/doc/tor.1.txt index 5d4b51c..bdc78ea 100644 --- a/doc/tor.1.txt +++ b/doc/tor.1.txt @@ -1238,11 +1238,7 @@ The following options are useful only for clients (that is, if **PathBiasDropGuards** __NUM__ + -**PathBiasScaleThreshold** __NUM__ + - -**PathBiasMultFactor** __NUM__ + - -**PathBiasScaleFactor** __NUM__:: +**PathBiasScaleThreshold** __NUM__:: These options override the default behavior of Tor's (**currently experimental**) path bias detection algorithm. To try to find broken or misbehaving guard nodes, Tor looks for nodes where more than a certain @@ -1256,14 +1252,13 @@ The following options are useful only for clients (that is, if is set to 1, we disable use of that guard. + + When we have seen more than PathBiasScaleThreshold - circuits through a guard, we scale our observations by - PathBiasMultFactor/PathBiasScaleFactor, so that new observations don't get - swamped by old ones. + + circuits through a guard, we scale our observations by 0.5 (governed by + the consensus) so that new observations don't get swamped by old ones. + + By default, or if a negative value is provided for one of these options, Tor uses reasonable defaults from the networkstatus consensus document. If no defaults are available there, these options default to 150, .70, - .50, .30, 0, 300, 1, and 2 respectively. + .50, .30, 0, and 300 respectively. **PathBiasUseThreshold** __NUM__ + diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c index 958e410..4f4f391 100644 --- a/src/or/circuitbuild.c +++ b/src/or/circuitbuild.c @@ -1175,38 +1175,31 @@ pathbias_get_scale_threshold(const or_options_t *options) } /** - * The scale factor is the denominator for our scaling - * of circuit counts for our path bias window. + * Compute the path bias scaling ratio from the consensus + * parameters pb_multfactor/pb_scalefactor. * - * Note that our use of doubles for the path bias state - * file means that powers of 2 work best here. + * Returns a value in (0, 1.0] which we multiply our pathbias + * counts with to scale them down. */ -static int -pathbias_get_scale_factor(const or_options_t *options) -{ -#define DFLT_PATH_BIAS_SCALE_FACTOR 2 - if (options->PathBiasScaleFactor >= 1) - return options->PathBiasScaleFactor; - else - return networkstatus_get_param(NULL, "pb_scalefactor", - DFLT_PATH_BIAS_SCALE_FACTOR, 1, INT32_MAX); -} - -/** - * The mult factor is the numerator for our scaling - * of circuit counts for our path bias window. It - * allows us to scale by fractions. - */ -static int -pathbias_get_mult_factor(const or_options_t *options) +static double +pathbias_get_scale_ratio(const or_options_t *options) { -#define DFLT_PATH_BIAS_MULT_FACTOR 1 - if (options->PathBiasMultFactor >= 1) - return options->PathBiasMultFactor; - else - return networkstatus_get_param(NULL, "pb_multfactor", - DFLT_PATH_BIAS_MULT_FACTOR, 1, - pathbias_get_scale_factor(options)); + /* + * The scale factor is the denominator for our scaling + * of circuit counts for our path bias window. + * + * Note that our use of doubles for the path bias state + * file means that powers of 2 work best here. + */ + int denominator = networkstatus_get_param(NULL, "pb_scalefactor", + 2, 2, INT32_MAX); + /** + * The mult factor is the numerator for our scaling + * of circuit counts for our path bias window. It + * allows us to scale by fractions. + */ + return networkstatus_get_param(NULL, "pb_multfactor", + 1, 1, denominator)/((double)denominator); } /** The minimum number of circuit usage attempts before we start @@ -2301,17 +2294,13 @@ pathbias_check_use_rate(entry_guard_t *guard) /* If we get a ton of circuits, just scale everything down */ 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); + double scale_ratio = pathbias_get_scale_ratio(options); int opened_attempts = pathbias_count_circs_in_states(guard, PATH_STATE_USE_ATTEMPTED, PATH_STATE_USE_SUCCEEDED); guard->use_attempts -= opened_attempts; - guard->use_attempts *= mult_factor; - guard->use_successes *= mult_factor; - - guard->use_attempts /= scale_factor; - guard->use_successes /= scale_factor; + guard->use_attempts *= scale_ratio; + guard->use_successes *= scale_ratio; guard->use_attempts += opened_attempts; @@ -2449,8 +2438,7 @@ pathbias_check_close_rate(entry_guard_t *guard) /* If we get a ton of circuits, just scale everything down */ 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); + double scale_ratio = pathbias_get_scale_ratio(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, @@ -2459,19 +2447,12 @@ pathbias_check_close_rate(entry_guard_t *guard) guard->circ_attempts -= opened_attempts; guard->circ_successes -= opened_built; - guard->circ_attempts *= mult_factor; - guard->circ_successes *= mult_factor; - guard->timeouts *= mult_factor; - guard->successful_circuits_closed *= mult_factor; - guard->collapsed_circuits *= mult_factor; - guard->unusable_circuits *= mult_factor; - - guard->circ_attempts /= scale_factor; - guard->circ_successes /= scale_factor; - guard->timeouts /= scale_factor; - guard->successful_circuits_closed /= scale_factor; - guard->collapsed_circuits /= scale_factor; - guard->unusable_circuits /= scale_factor; + guard->circ_attempts *= scale_ratio; + guard->circ_successes *= scale_ratio; + guard->timeouts *= scale_ratio; + guard->successful_circuits_closed *= scale_ratio; + guard->collapsed_circuits *= scale_ratio; + guard->unusable_circuits *= scale_ratio; guard->circ_attempts += opened_attempts; guard->circ_successes += opened_built; diff --git a/src/or/config.c b/src/or/config.c index 74b635e..70d8703 100644 --- a/src/or/config.c +++ b/src/or/config.c @@ -321,8 +321,8 @@ static config_var_t option_vars_[] = { V(PathBiasWarnRate, DOUBLE, "-1"), V(PathBiasExtremeRate, DOUBLE, "-1"), V(PathBiasScaleThreshold, INT, "-1"), - V(PathBiasScaleFactor, INT, "-1"), - V(PathBiasMultFactor, INT, "-1"), + OBSOLETE("PathBiasScaleFactor"), + OBSOLETE("PathBiasMultFactor"), V(PathBiasDropGuards, AUTOBOOL, "0"), OBSOLETE("PathBiasUseCloseCounts"), diff --git a/src/or/or.h b/src/or/or.h index 3c962e3..e5fc06a 100644 --- a/src/or/or.h +++ b/src/or/or.h @@ -3949,8 +3949,6 @@ typedef struct { double PathBiasExtremeRate; int PathBiasDropGuards; int PathBiasScaleThreshold; - int PathBiasScaleFactor; - int PathBiasMultFactor; /** @} */ /**