commit 98be8634faf4405edc5388c64d9f834b6ae5b4b1 Author: Mike Perry mikeperry-git@torproject.org Date: Tue Sep 28 17:44:33 2021 +0000

Turn CircEWMA tick len into consensus parameter.

This will assist tuning of CircEWMA in Shadow and Live. --- src/core/or/circuitmux_ewma.c | 26 +++++++++++++++++--------- 1 file changed, 17 insertions(+), 9 deletions(-)

diff --git a/src/core/or/circuitmux_ewma.c b/src/core/or/circuitmux_ewma.c index 0382e62f75..adf256ab05 100644 --- a/src/core/or/circuitmux_ewma.c +++ b/src/core/or/circuitmux_ewma.c @@ -45,7 +45,10 @@ /*** EWMA parameter #defines ***/

/** How long does a tick last (seconds)? */ -#define EWMA_TICK_LEN 10 +#define EWMA_TICK_LEN_DEFAULT 10 +#define EWMA_TICK_LEN_MIN 1 +#define EWMA_TICK_LEN_MAX 600 +static int ewma_tick_len = EWMA_TICK_LEN_DEFAULT;

/** The default per-tick scale factor, if it hasn't been overridden by a * consensus or a configuration setting. zero means "disabled". */ @@ -148,7 +151,7 @@ cell_ewma_get_tick(void) monotime_coarse_get(&now); int32_t msec_diff = monotime_coarse_diff_msec32(&start_of_current_tick, &now); - return current_tick_num + msec_diff / (1000*EWMA_TICK_LEN); + return current_tick_num + msec_diff / (1000*ewma_tick_len); }

/** @@ -527,15 +530,15 @@ cell_ewma_get_current_tick_and_fraction(double *remainder_out) monotime_coarse_get(&now); int32_t msec_diff = monotime_coarse_diff_msec32(&start_of_current_tick, &now); - if (msec_diff > (1000*EWMA_TICK_LEN)) { - unsigned ticks_difference = msec_diff / (1000*EWMA_TICK_LEN); + if (msec_diff > (1000*ewma_tick_len)) { + unsigned ticks_difference = msec_diff / (1000*ewma_tick_len); monotime_coarse_add_msec(&start_of_current_tick, &start_of_current_tick, - ticks_difference * 1000 * EWMA_TICK_LEN); + ticks_difference * 1000 * ewma_tick_len); current_tick_num += ticks_difference; - msec_diff %= 1000*EWMA_TICK_LEN; + msec_diff %= 1000*ewma_tick_len; } - *remainder_out = ((double)msec_diff) / (1.0e3 * EWMA_TICK_LEN); + *remainder_out = ((double)msec_diff) / (1.0e3 * ewma_tick_len); return current_tick_num; }

@@ -605,15 +608,20 @@ cmux_ewma_set_options(const or_options_t *options, /* Both options and consensus can be NULL. This assures us to either get a * valid configured value or the default one. */ halflife = get_circuit_priority_halflife(options, consensus, &source); + ewma_tick_len = networkstatus_get_param(consensus, + "CircuitPriorityTickSecs", + EWMA_TICK_LEN_DEFAULT, + EWMA_TICK_LEN_MIN, + EWMA_TICK_LEN_MAX);

/* convert halflife into halflife-per-tick. */ - halflife /= EWMA_TICK_LEN; + halflife /= ewma_tick_len; /* compute per-tick scale factor. */ ewma_scale_factor = exp(LOG_ONEHALF / halflife); log_info(LD_OR, "Enabled cell_ewma algorithm because of value in %s; " "scale factor is %f per %d seconds", - source, ewma_scale_factor, EWMA_TICK_LEN); + source, ewma_scale_factor, ewma_tick_len); }

/** Return the multiplier necessary to convert the value of a cell sent in