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[or-cvs] [tor/master] Remove trailing spaces. As if bytes were free...
Author: Karsten Loesing <karsten.loesing@xxxxxxx>
Date: Thu, 3 Sep 2009 14:44:01 +0200
Subject: Remove trailing spaces. As if bytes were free...
Commit: b508e4748f42436ad1e9b05970cc4d3c5c1debfc
Also correct some typos.
---
.../proposals/151-path-selection-improvements.txt | 52 ++++++++++----------
src/or/circuitbuild.c | 9 ++--
2 files changed, 31 insertions(+), 30 deletions(-)
diff --git a/doc/spec/proposals/151-path-selection-improvements.txt b/doc/spec/proposals/151-path-selection-improvements.txt
index df19e0f..7821a5d 100644
--- a/doc/spec/proposals/151-path-selection-improvements.txt
+++ b/doc/spec/proposals/151-path-selection-improvements.txt
@@ -8,7 +8,7 @@ Overview
The performance of paths selected can be improved by adjusting the
CircuitBuildTimeout and avoiding failing guard nodes. This proposal
- describes a method of tracking buildtime statistics at the client, and
+ describes a method of tracking buildtime statistics at the client, and
using those statistics to adjust the CircuitBuildTimeout.
Motivation
@@ -30,15 +30,15 @@ Implementation
too large, because it will make it difficult for clients to adapt to
moving between different links.
- From our observations, this value appears to be on the order of 1000,
+ From our observations, this value appears to be on the order of 1000,
but is configurable in a #define NCIRCUITS_TO_OBSERVE.
-
+
Long Term Storage
- The long-term storage representation is implemented by storing a
- histogram with BUILDTIME_BIN_WIDTH millisecond buckets (default 50) when
+ The long-term storage representation is implemented by storing a
+ histogram with BUILDTIME_BIN_WIDTH millisecond buckets (default 50) when
writing out the statistics to disk. The format this takes in the
- state file is 'CircuitBuildTime <bin-ms> <count>', with the total
+ state file is 'CircuitBuildTime <bin-ms> <count>', with the total
specified as 'TotalBuildTimes <total>'
Example:
@@ -57,7 +57,7 @@ Implementation
Learning the CircuitBuildTimeout
Based on studies of build times, we found that the distribution of
- circuit buildtimes appears to be a Pareto distribution.
+ circuit buildtimes appears to be a Pareto distribution.
We will calculate the parameters for a Pareto distribution
fitting the data using the estimators at
@@ -68,7 +68,7 @@ Implementation
BUILDTIME_PERCENT_CUTOFF (80%) of the mass of the distribution is
below the timeout value.
- Thus, we expect that the Tor client will accept the fastest 80% of
+ Thus, we expect that the Tor client will accept the fastest 80% of
the total number of paths on the network.
Detecting Changing Network Conditions
@@ -76,65 +76,65 @@ Implementation
We attempt to detect both network connectivty loss and drastic
changes in the timeout characteristics. Network connectivity loss
is detected by recording a timestamp every time Tor either completes
- a TLS connection or receives a cell. If this timestamp is more than
+ a TLS connection or receives a cell. If this timestamp is more than
90 seconds in the past, circuit timeouts are no longer counted.
- If more than MAX_RECENT_TIMEOUT_RATE (80%) of the past
+ If more than MAX_RECENT_TIMEOUT_RATE (80%) of the past
RECENT_CIRCUITS (20) time out, we assume the network connection
has changed, and we discard all buildtimes history and compute
a new timeout by estimating a new Pareto curve using the
position on the Pareto Quartile function for the ratio of
- timeouts.
+ timeouts.
Testing
After circuit build times, storage, and learning are implemented,
the resulting histogram should be checked for consistency by
- verifying it persists across successive Tor invocations where
+ verifying it persists across successive Tor invocations where
no circuits are built. In addition, we can also use the existing
- buildtime scripts to record build times, and verify that the histogram
+ buildtime scripts to record build times, and verify that the histogram
the python produces matches that which is output to the state file in Tor,
and verify that the Pareto parameters and cutoff points also match.
-
+
Soft timeout vs Hard Timeout
-
- At some point, it may be desirable to change the cutoff from a
+
+ At some point, it may be desirable to change the cutoff from a
single hard cutoff that destroys the circuit to a soft cutoff and
a hard cutoff, where the soft cutoff merely triggers the building
- of a new circuit, and the hard cutoff triggers destruction of the
+ of a new circuit, and the hard cutoff triggers destruction of the
circuit.
- Good values for hard and soft cutoffs seem to be 80% and 60%
+ Good values for hard and soft cutoffs seem to be 80% and 60%
respectively, but we should eventually justify this with observation.
When to Begin Calculation
- The number of circuits to observe (NCIRCUITS_TO_CUTOFF) before
- changing the CircuitBuildTimeout will be tunable via a #define. From
- our measurements, a good value for NCIRCUITS_TO_CUTOFF appears to be
+ The number of circuits to observe (NCIRCUITS_TO_CUTOFF) before
+ changing the CircuitBuildTimeout will be tunable via a #define. From
+ our measurements, a good value for NCIRCUITS_TO_CUTOFF appears to be
on the order of 100.
Dealing with Timeouts
- Timeouts should be counted as the expectation of the region of
+ Timeouts should be counted as the expectation of the region of
of the Pareto distribution beyond the cutoff. The proposal will
be updated with this value soon.
- Also, in the event of network failure, the observation mechanism
+ Also, in the event of network failure, the observation mechanism
should stop collecting timeout data.
Client Hints
Some research still needs to be done to provide initial values
for CircuitBuildTimeout based on values learned from modem
- users, DSL users, Cable Modem users, and dedicated links. A
+ users, DSL users, Cable Modem users, and dedicated links. A
radiobutton in Vidalia should eventually be provided that
- sets CircuitBuildTimeout to one of these values and also
+ sets CircuitBuildTimeout to one of these values and also
provide the option of purging all learned data, should any exist.
These values can either be published in the directory, or
shipped hardcoded for a particular Tor version.
-
+
Issues
Impact on anonymity
diff --git a/src/or/circuitbuild.c b/src/or/circuitbuild.c
index 0a55d8f..39e5a43 100644
--- a/src/or/circuitbuild.c
+++ b/src/or/circuitbuild.c
@@ -308,7 +308,7 @@ circuit_build_times_parse_state(circuit_build_times_t *cbt,
SPLIT_SKIP_SPACE|SPLIT_IGNORE_BLANK, 0);
if (smartlist_len(args) < 2) {
*msg = tor_strdup("Unable to parse circuit build times: "
- "Too few arguments to CircuitBuildTIme");
+ "Too few arguments to CircuitBuildTime");
break;
} else {
const char *ms_str = smartlist_get(args,0);
@@ -375,7 +375,7 @@ circuit_build_times_update_alpha(circuit_build_times_t *cbt)
}
if (n!=cbt->total_build_times) {
- log_err(LD_CIRC, "Discrepency in build times count: %d vs %d", n,
+ log_err(LD_CIRC, "Discrepancy in build times count: %d vs %d", n,
cbt->total_build_times);
}
tor_assert(n==cbt->total_build_times);
@@ -396,7 +396,8 @@ circuit_build_times_update_alpha(circuit_build_times_t *cbt)
*
* See http://en.wikipedia.org/wiki/Quantile_function,
* http://en.wikipedia.org/wiki/Inverse_transform_sampling and
- * http://en.wikipedia.org/wiki/Pareto_distribution#Generating_a_random_sample_from_Pareto_distribution
+ * http://en.wikipedia.org/wiki/Pareto_distribution#Generating_a_
+ * random_sample_from_Pareto_distribution
* That's right. I'll cite wikipedia all day long.
*/
double
@@ -551,7 +552,7 @@ circuit_build_times_check_too_many_timeouts(circuit_build_times_t *cbt)
}
timeout_rate /= RECENT_CIRCUITS;
- /* If more then 80% of our recent circuits are timing out,
+ /* If more than 80% of our recent circuits are timing out,
* we need to re-estimate a new initial alpha and timeout */
if (timeout_rate < MAX_RECENT_TIMEOUT_RATE) {
return 0;
--
1.5.6.5