Commit 38770dd6 authored by Mike Perry's avatar Mike Perry
Browse files

Add timeout count state variable.

parent 848d9f8b

src/or/circuitbuild.c

+60 −57
Original line number Diff line number Diff line
@@ -470,6 +470,12 @@ circuit_build_times_update_state(circuit_build_times_t *cbt, 
  *next = NULL;



  state->TotalBuildTimes = cbt->total_build_times;

  state->CircuitBuildTimeoutCount = 0;



  for (i = 0; i < CBT_NCIRCUITS_TO_OBSERVE; i++) {

    if (cbt->circuit_build_times[i] == CBT_BUILD_TIMEOUT)

      state->CircuitBuildTimeoutCount++;

  }



  for (i = 0; i < nbins; i++) {

    // compress the histogram by skipping the blanks
@@ -521,6 +527,40 @@ 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.

 */

static int

circuit_build_times_filter_timeouts(circuit_build_times_t *cbt)

{

  int num_filtered=0, i=0;

  double timeout_rate = 0;

  build_time_t max_timeout = 0;



  timeout_rate = circuit_build_times_timeout_rate(cbt);

  max_timeout = (build_time_t)cbt->timeout_ms;



  for (i = 0; i < CBT_NCIRCUITS_TO_OBSERVE; i++) {

    if (cbt->circuit_build_times[i] > max_timeout) {

      build_time_t replaced = cbt->circuit_build_times[i];

      num_filtered++;

      cbt->circuit_build_times[i] = CBT_BUILD_TIMEOUT;



      log_debug(LD_CIRC, "Replaced timeout %d with %d", replaced,

               cbt->circuit_build_times[i]);

    }

  }



  log_info(LD_CIRC,

           "We had %d timeouts out of %d build times, "

           "and filtered %d above the max of %u",

          (int)(cbt->total_build_times*timeout_rate),

          cbt->total_build_times, num_filtered, max_timeout);



  return num_filtered;

}



/**

 * Load histogram from <b>state</b>, shuffling the resulting array

 * after we do so. Use this result to estimate parameters and
@@ -535,7 +575,7 @@ circuit_build_times_parse_state(circuit_build_times_t *cbt, 
  int tot_values = 0;

  uint32_t loaded_cnt = 0, N = 0;

  config_line_t *line;

  int i;

  unsigned int i;

  build_time_t *loaded_times;

  circuit_build_times_init(cbt);

  *msg = NULL;
@@ -581,7 +621,8 @@ circuit_build_times_parse_state(circuit_build_times_t *cbt, 
        break;

      }



      if (loaded_cnt+count > state->TotalBuildTimes) {

      if (loaded_cnt+count+state->CircuitBuildTimeoutCount

            > state->TotalBuildTimes) {

        log_warn(LD_CIRC,

                 "Too many build times in state file. "

                 "Stopping short before %d",
@@ -600,10 +641,17 @@ circuit_build_times_parse_state(circuit_build_times_t *cbt, 
    }

  }



  log_info(LD_CIRC,

           "Adding %d timeouts.", state->CircuitBuildTimeoutCount);

  for (i=0; i < state->CircuitBuildTimeoutCount; i++) {

    loaded_times[loaded_cnt++] = CBT_BUILD_TIMEOUT;

  }



  if (loaded_cnt != state->TotalBuildTimes) {

    log_warn(LD_CIRC,

            "Corrupt state file? Build times count mismatch. "

            "Read %d, file says %d", loaded_cnt, state->TotalBuildTimes);

            "Read %d times, but file says %d", loaded_cnt,

            state->TotalBuildTimes);

  }



  circuit_build_times_shuffle_and_store_array(cbt, loaded_times, loaded_cnt);
@@ -619,7 +667,13 @@ circuit_build_times_parse_state(circuit_build_times_t *cbt, 
           tot_values, cbt->total_build_times, N);

  tor_assert(cbt->total_build_times == tot_values);

  tor_assert(cbt->total_build_times <= CBT_NCIRCUITS_TO_OBSERVE);



  circuit_build_times_set_timeout(cbt);



  if (!state->CircuitBuildTimeoutCount) {

    circuit_build_times_filter_timeouts(cbt);

  }



  tor_free(loaded_times);

  return *msg ? -1 : 0;

}
@@ -676,6 +730,9 @@ circuit_build_times_update_alpha(circuit_build_times_t *cbt) 
  a += timeout_count*tor_mathlog(max_time);



  a -= n*tor_mathlog(cbt->Xm);

  // Estimator comes from Eq #4 in:

  // "Bayesian estimation based on trimmed samples from Pareto populations"

  // by Arturo J. Fernández. We are right-censored only.

  a = (n-timeout_count)/a;



  cbt->alpha = a;
@@ -1015,55 +1072,6 @@ circuit_build_times_add_timeout(circuit_build_times_t *cbt, 
  return 1;

}



static int

circuit_build_times_filter_timeouts(circuit_build_times_t *cbt)

{

  int num_filtered=0, i=0;

  double timeout_rate = 0;

  build_time_t max_timeout = 0;



  /* If we replace high timeouts when the curve is really steep

   * (alpha is above ~1.5), we can end up with a lot of timeouts clustered

   * really close to the current timeout value, which makes the next

   * alpha even higher, which makes us filter out more, and this becomes

   * progressively worse until the timeout *is* Xm. Filtering should

   * only be done on really shallow curves anyway. */

  if (cbt->alpha > 1.5) {

    return 0;

  }



  /* Do not filter for unit tests. They expect the distribution to be

   * unchanged from run to run. */

  if (unit_tests) {

    return 0;

  }



  timeout_rate = circuit_build_times_timeout_rate(cbt);

  max_timeout = /*(build_time_t)tor_lround(circuit_build_times_calculate_timeout(cbt,

                    circuit_build_times_max_synthetic_quantile()));*/

                (build_time_t)cbt->timeout_ms;



  /* XXX: Make a special bin for timeout values */

  for (i = 0; i < CBT_NCIRCUITS_TO_OBSERVE; i++) {

    if (cbt->circuit_build_times[i] > max_timeout) {

      build_time_t replaced = cbt->circuit_build_times[i];

      num_filtered++;

      cbt->circuit_build_times[i] = CBT_BUILD_TIMEOUT;



      log_debug(LD_CIRC, "Replaced timeout %d with %d", replaced,

               cbt->circuit_build_times[i]);

    }

  }



  log_info(LD_CIRC,

           "We had %d timeouts out of %d build times, "

           "and filtered %d above the max of %u",

          (int)(cbt->total_build_times*timeout_rate),

          cbt->total_build_times, num_filtered, max_timeout);



  return num_filtered;

}



/**

 * Estimate a new timeout based on history and set our timeout

 * variable accordingly.
@@ -1091,16 +1099,11 @@ void 
circuit_build_times_set_timeout(circuit_build_times_t *cbt)

{

  long prev_timeout = tor_lround(cbt->timeout_ms/1000);

  int filtered=0;

  double timeout_rate;



  if (!circuit_build_times_set_timeout_worker(cbt))

    return;



  if ((filtered = circuit_build_times_filter_timeouts(cbt)) > 0) {

    circuit_build_times_set_timeout_worker(cbt);

  }



  if (cbt->timeout_ms < circuit_build_times_min_timeout()) {

    log_warn(LD_CIRC, "Set buildtimeout to low value %lfms. Setting to %dms",

             cbt->timeout_ms, circuit_build_times_min_timeout());

src/or/config.c

+1 −0
Original line number Diff line number Diff line
@@ -421,6 +421,7 @@ static config_var_t _state_vars[] = { 
  V(LastWritten,                      ISOTIME,  NULL),



  V(TotalBuildTimes,                  UINT,     NULL),

  V(CircuitBuildTimeoutCount,         UINT,     "0"),

  VAR("CircuitBuildTimeBin",          LINELIST_S, BuildtimeHistogram, NULL),

  VAR("BuildtimeHistogram",           LINELIST_V, BuildtimeHistogram, NULL),

src/or/or.h

+2 −1
Original line number Diff line number Diff line
@@ -2841,7 +2841,8 @@ typedef struct { 


  /** Build time histogram */

  config_line_t * BuildtimeHistogram;

  uint16_t TotalBuildTimes;

  unsigned int TotalBuildTimes;

  unsigned int CircuitBuildTimeoutCount;



  /** What version of Tor wrote this state file? */

  char *TorVersion;