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Keep circuits open until the greater of 95th CDF percentile or 60s.

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This is done to provide better data to our right-censored Pareto model.

We do this by simply marking them with a new purpose.
This commit is contained in:
Mike Perry 2010-06-08 01:01:47 -07:00
parent 81736f426f
commit c96206090e
3 changed files with 73 additions and 21 deletions
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43
src/or/circuitbuild.c
View File

@ -139,6 +139,15 @@ circuit_build_times_quantile_cutoff(void)
return num/100.0;
}
static double
circuit_build_times_close_quantile(void)
{
int32_t num = networkstatus_get_param(NULL, "cbtclosequantile",
CBT_DEFAULT_CLOSE_QUANTILE);
return num/100.0;
}
static int32_t
circuit_build_times_test_frequency(void)
{
@ -539,7 +548,10 @@ circuit_build_times_shuffle_and_store_array(circuit_build_times_t *cbt,
/**
* Filter old synthetic timeouts that were created before the
* right censored new Pareto calculation was deployed.
* new right-censored Pareto calculation was deployed.
*
* Once all clients before 0.2.1.13-alpha are gone, this code
* will be unused.
*/
static int
circuit_build_times_filter_timeouts(circuit_build_times_t *cbt)
@ -549,7 +561,7 @@ circuit_build_times_filter_timeouts(circuit_build_times_t *cbt)
build_time_t max_timeout = 0;
timeout_rate = circuit_build_times_timeout_rate(cbt);
max_timeout = (build_time_t)cbt->timeout_ms;
max_timeout = (build_time_t)cbt->close_ms;
for (i = 0; i < CBT_NCIRCUITS_TO_OBSERVE; i++) {
if (cbt->circuit_build_times[i] > max_timeout) {
@ -1097,6 +1109,15 @@ circuit_build_times_set_timeout_worker(circuit_build_times_t *cbt)
cbt->timeout_ms = circuit_build_times_calculate_timeout(cbt,
circuit_build_times_quantile_cutoff());
cbt->close_ms = circuit_build_times_calculate_timeout(cbt,
circuit_build_times_close_quantile());
/* Sometimes really fast guard nodes give us such a steep curve
* that this ends up being not that much greater than timeout_ms.
* Make it be at least 1 min to handle this case. */
cbt->close_ms = MAX(cbt->close_ms, 60*1000);
cbt->have_computed_timeout = 1;
return 1;
}
@ -1132,8 +1153,9 @@ circuit_build_times_set_timeout(circuit_build_times_t *cbt)
cbt->total_build_times,
tor_lround(cbt->timeout_ms/1000));
log_info(LD_CIRC,
"Circuit timeout data: %lfms, Xm: %d, a: %lf, r: %lf",
cbt->timeout_ms, cbt->Xm, cbt->alpha, timeout_rate);
"Circuit timeout data: %lfms, %lfms, Xm: %d, a: %lf, r: %lf",
cbt->timeout_ms, cbt->close_ms, cbt->Xm, cbt->alpha,
timeout_rate);
} else if (prev_timeout < tor_lround(cbt->timeout_ms/1000)) {
log_notice(LD_CIRC,
"Based on %d circuit times, it looks like we need to wait "
@ -1142,14 +1164,15 @@ circuit_build_times_set_timeout(circuit_build_times_t *cbt)
cbt->total_build_times,
tor_lround(cbt->timeout_ms/1000));
log_info(LD_CIRC,
"Circuit timeout data: %lfms, Xm: %d, a: %lf, r: %lf",
cbt->timeout_ms, cbt->Xm, cbt->alpha, timeout_rate);
"Circuit timeout data: %lfms, %lfms, Xm: %d, a: %lf, r: %lf",
cbt->timeout_ms, cbt->close_ms, cbt->Xm, cbt->alpha,
timeout_rate);
} else {
log_info(LD_CIRC,
"Set circuit build timeout to %lds (%lfms, Xm: %d, a: %lf, "
"r: %lf) based on %d circuit times",
"Set circuit build timeout to %lds (%lfms, %lfms, Xm: %d, a: %lf,"
" r: %lf) based on %d circuit times",
tor_lround(cbt->timeout_ms/1000),
cbt->timeout_ms, cbt->Xm, cbt->alpha, timeout_rate,
cbt->timeout_ms, cbt->close_ms, cbt->Xm, cbt->alpha, timeout_rate,
cbt->total_build_times);
}
}
@ -1747,7 +1770,7 @@ circuit_send_next_onion_skin(origin_circuit_t *circ)
* it off at, we probably had a suspend event along this codepath,
* and we should discard the value.
*/
if (timediff < 0 || timediff > 2*circ_times.timeout_ms+1000) {
if (timediff < 0 || timediff > 2*circ_times.close_ms+1000) {
log_notice(LD_CIRC, "Strange value for circuit build time: %ld. "
"Assuming clock jump.", timediff);
} else if (!circuit_build_times_disabled()) {

23
src/or/circuituse.c
View File

@ -270,6 +270,7 @@ circuit_expire_building(time_t now)
* decided on a customized one yet */
time_t general_cutoff = now - lround(circ_times.timeout_ms/1000);
time_t begindir_cutoff = now - lround(circ_times.timeout_ms/2000);
time_t close_cutoff = now - lround(circ_times.close_ms/1000);
time_t introcirc_cutoff = begindir_cutoff;
cpath_build_state_t *build_state;
@ -286,8 +287,11 @@ circuit_expire_building(time_t now)
cutoff = begindir_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_C_INTRODUCING)
cutoff = introcirc_cutoff;
else if (victim->purpose == CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT)
cutoff = close_cutoff;
else
cutoff = general_cutoff;
if (victim->timestamp_created > cutoff)
continue; /* it's still young, leave it alone */
@ -350,12 +354,29 @@ circuit_expire_building(time_t now)
} else { /* circuit not open, consider recording failure as timeout */
int first_hop_succeeded = TO_ORIGIN_CIRCUIT(victim)->cpath &&
TO_ORIGIN_CIRCUIT(victim)->cpath->state == CPATH_STATE_OPEN;
if (TO_ORIGIN_CIRCUIT(victim)->p_streams != NULL) {
log_warn(LD_BUG, "Circuit %d (purpose %d) has timed out, "
"yet has attached streams!",
TO_ORIGIN_CIRCUIT(victim)->global_identifier,
victim->purpose);
tor_fragile_assert();
continue;
}
/* circuits are allowed to last longer for measurement.
* Switch their purpose and wait. */
if (victim->purpose != CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT) {
victim->purpose = CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT;
continue;
}
/*
* If the circuit build time is much greater than we would have cut
* it off at, we probably had a suspend event along this codepath,
* and we should discard the value.
*/
if (now - victim->timestamp_created > (2*circ_times.timeout_ms)/1000+1) {
if (now - victim->timestamp_created > 2*circ_times.close_ms/1000+1) {
log_notice(LD_CIRC,
"Extremely large value for circuit build timeout: %ld. "
"Assuming clock jump.", now - victim->timestamp_created);

28
src/or/or.h
View File

@ -467,23 +467,23 @@ typedef enum {
#define CIRCUIT_PURPOSE_C_REND_READY_INTRO_ACKED 11
/** Client-side circuit purpose: at Alice, rendezvous established. */
#define CIRCUIT_PURPOSE_C_REND_JOINED 12
#define _CIRCUIT_PURPOSE_C_MAX 12
/** This circuit is used for build time measurement only */
#define CIRCUIT_PURPOSE_C_MEASURE_TIMEOUT 13
#define _CIRCUIT_PURPOSE_C_MAX 13
/** Hidden-service-side circuit purpose: at Bob, waiting for introductions. */
#define CIRCUIT_PURPOSE_S_ESTABLISH_INTRO 13
#define CIRCUIT_PURPOSE_S_ESTABLISH_INTRO 14
/** Hidden-service-side circuit purpose: at Bob, successfully established
* intro. */
#define CIRCUIT_PURPOSE_S_INTRO 14
#define CIRCUIT_PURPOSE_S_INTRO 15
/** Hidden-service-side circuit purpose: at Bob, connecting to rend point. */
#define CIRCUIT_PURPOSE_S_CONNECT_REND 15
#define CIRCUIT_PURPOSE_S_CONNECT_REND 16
/** Hidden-service-side circuit purpose: at Bob, rendezvous established. */
#define CIRCUIT_PURPOSE_S_REND_JOINED 16
#define CIRCUIT_PURPOSE_S_REND_JOINED 17
/** A testing circuit; not meant to be used for actual traffic. */
#define CIRCUIT_PURPOSE_TESTING 17
#define CIRCUIT_PURPOSE_TESTING 18
/** A controller made this circuit and Tor should not use it. */
#define CIRCUIT_PURPOSE_CONTROLLER 18
#define _CIRCUIT_PURPOSE_MAX 18
#define CIRCUIT_PURPOSE_CONTROLLER 19
#define _CIRCUIT_PURPOSE_MAX 19
/** A catch-all for unrecognized purposes. Currently we don't expect
* to make or see any circuits with this purpose. */
#define CIRCUIT_PURPOSE_UNKNOWN 255
@ -3055,6 +3055,12 @@ typedef uint32_t build_time_t;
/* Circuit build times consensus parameters */
/**
* How long to wait before actually closing circuits that take too long to
* build in terms of CDF quantile.
*/
#define CBT_DEFAULT_CLOSE_QUANTILE 95
/**
* How many circuits count as recent when considering if the
* connection has gone gimpy or changed.
@ -3134,6 +3140,8 @@ typedef struct {
/** The exact value for that timeout in milliseconds. Stored as a double
* to maintain precision from calculations to and from quantile value. */
double timeout_ms;
/** How long we wait before actually closing the circuit. */
double close_ms;
} circuit_build_times_t;
extern circuit_build_times_t circ_times;