Changes between Version 21 and Version 22 of doc/FireFoxTorPerf


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Timestamp:
Apr 23, 2010, 4:47:54 AM (9 years ago)
Author:
trac
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  • doc/FireFoxTorPerf

    v21 v22  
    22
    33== Introduction ==
     4
    45Tor is known for being secure but slow. If you want to improve browsing speed a bit, please follow the following simple instructions for tweaking the Firefox web browser's settings:
    56
    6 == Table of contents ==
    7  * Procedure 1
    8  * Procedure 2
    9  * The proof is in the pudding, results
    10  * Advanced Tuning for Windows
     7== Procedure 1 ==
    118
    12 == Procedure 1 ==
    139First, open Firefox's advanced settings menu by running ''about:config'' from the address bar. Upon entering this address, you will see a long list of internal settings. Modify the following ones and set them to the suggested values shown here for maximum performance:
    1410
    15 {{{
    16 network.http.keep-alive.timeout:600 (300ms default is OK usually, but 600 is better.)
     11{{{ network.http.keep-alive.timeout:600 (300ms default is OK usually, but 600 is better.)
    1712network.http.max-persistent-connections-per-proxy:16 (Default is 4)
    1813network.http.pipelining:true (Default- false. Some old HTTP/1.0 servers can't handle it.)
    1914network.http.pipelining.maxrequests:8 (No default)
    2015network.http.proxy.keep-alive:true (Default- true, but double check)
    21 network.http.proxy.pipelining:true (Default- false) - See NOTE1 below.}}}
    22 Afterwards, just restart the browser and experience the difference! For some automated additional performance hacks, check out [http://www.totalidea.com/freestuff4.htm FireTune]. Currently, Fire{{{}}}Tune is only for Win32, but you can do the same tweaks manually with the help of [http://www.tweakfactor.com/articles/tweaks/firefoxtweak/4.html this page].
     16network.http.proxy.pipelining:true (Default- false) }}}
    2317
    24 NOTE1: Proxy pipelining may not be well supported by Privoxy. For this reason, you may want to install [http://www.pps.jussieu.fr/~jch/software/polipo/ Polipo] and use that instead of Privoxy to get the performance benefits of pipelining. If you use [https://torbutton.torproject.org/ Torbutton] (which you should, if you want [https://www.torproject.org/torbutton/design/#attacks any anonymity at all]), all of the Tor-relevant privacy scrubbing features of Privoxy are no longer necessary.
     18Afterwards, just restart the browser and experience the difference! For some automated additional performance hacks, check out [http://www.totalidea.com/freestuff4.htm FireTune]. Currently, Fire``Tune is only for Win32, but you can do the same tweaks manually with the help of [http://www.tweakfactor.com/articles/tweaks/firefoxtweak/4.html this page]. Additionally, there is the [http://fasterfox.mozdev.org/ FasterFox extension] that is easy to install, and is also '''platform independent'''!
    2519
    26 NOTE2: Do not use page prefetching. Disable this if it is enabled. Prefetching is a speculative feature, which assumes that you will read the pages referenced by the links in the current page you are viewing. This places undue load on the Tor network and clog your circuits with unnecessary traffic. Its unlikely you will read all the pages referenced by the current page, especially in the case of search engines results.
     20== Procedure 2 - an update and addendum to Procedure 1 ==
    2721
    28 == Procedure 2 - A Tor Non-Functional Requirement (NFR) ==
    29 If you follow the previous authors work you should have well performing access. To go that bit further lets consider the ideal behaviour of our Tor client.
     22These results were arrived at empirically, using the win32 bundle, Tor & Privoxy & Vidalia bundle: 0.1.2.5-alpha
    3023
    31 You will need: [https://www.torproject.org/tor-manual.html.en The on-line reference to Tor properties, that can be placed in torrc.] Always back up this file before editing.
     24You will need the following tools...
     25 * [http://freehaven.net/~squires/torbutton/ Tor Button]
     26 * [http://fasterfox.mozdev.org/ FasterFox]
     27 * [http://www.prnwatch.com/prio.html Prio (win32)]
     28 * [http://www.speedguide.net/downloads.php TCPOptimizer (win32)]
     29 * [http://www.speedguide.net/read_articles.php?id=1497 Event ID 4226 Patcher (win32)]
    3230
    33 Lets think of a Non-Functional Requirement we might like to place on our Tor client.
     31== Tor Button - enable / disable TOR access in FireFox ==
     32This provides an optional button or text in the bottom right of the browser window in Firefox. This allows you to switch Tor on and off.
    3433
    35  * we want it to establish circuits as quickly as possible. If it takes too long to do this ignore them, by timing out the building of circuits quickly.
    36  * now we have circuit build time-outs occuring more frequently, we need to encourage Tor to try to generate circuits more often.
    37  * Once we have established a circuit, we are assuming its a good one and we dont want it being timed out by firewalls or anything else. We need to make sure a ping occurs on the circuit to prevent this.
    38 Given this NFR, lets come up with some properties that may help satisfy it.
     34== FasterFox - Modify performance related settings in FireFox ==
     35This plugin modifies the networking and cache settings for Firefox. The following settings need to be modified.
     36 * Initially you need to select 'Custom' in the FasterFox Options. This allows you to use your own detailed options, rather than the default schemes supplied.
     37 * Select the Cache tab.
     38  * Enter a Memory Cache Capacity of >= 8mb
     39  * Enter a Disk Cache Capacity of >= 8mb
     40 * Select the Connection tab
     41  * Enter Max Connection >= 128
     42  * Enter Max Connection Per Server >= 10
     43  * Enter Max Persistent Connection Per Server >= 8
     44  * Enter Max Persistent Connection Per Proxy >= 8
     45 * Select the Pipelining tab
     46  * Ensure all 3 tick options are enabled
     47  * Enter Max pipelining requests >= 10
    3948
    40  * CircuitBuildTimeout NUM
    41   . Try for at most NUM seconds when building circuits. If the circuit isn't open in that time, give up on it. (Default: 1 minute.) Force circuits that are quick to establish and thus likely to push traffic more quickly. Values as low as 2 seconds have been tried with good results, although this can cause severe damage to the Tor network if your network connection is simply not fast enough to establish any circuits in this time. The effect is a smaller 'Topological Radius' of servers used for Tor, ie the network connections available from your connection. Unfortunately, the smaller you make this number, the smaller the number of paths your client will use, and the less your anonymity.
    42  * NumEntryGuards NUM
    43   . If we are going to be decreasing the CircuitBuildTimeout, you want to increase the likelihood you have a guard node fast enough to build these fast circuits for you. NUM=5 to 8 are good choices here.
    44  * KeepalivePeriod NUM
    45   . To keep firewalls from expiring connections, send a padding keepalive cell every NUM seconds on open connections that are in use. If the connection has no open circuits, it will instead be closed after NUM seconds of idleness. (Default: 5 minutes)
    46  * NewCircuitPeriod NUM
    47   . Every NUM seconds consider whether to build a new circuit. (Default: 30 seconds) Lets make Tor ready to establish a new circuit more readily.
     49== Prio - Increase Tor process Priority (win32) ==
     50You will also realise a substantial increase in performance by increasing the process priority for the Tor process. You can do this in Task Manager after you identify tor.exe. If you want to persist the process priority you will need a Task Manager addon. An effective tool for doing this is [http://www.prnwatch.com/prio.html Prio]. This tool can only be used in a non-commercial setting, unless you license it.
     51I dont recommend modifying the process above 'high'. If Tor crashes or freezes windows will become unresponsive. Setting it to 'Above Normal' is a good start.
    4852
    49 Settings that you may append to the end of the torrc configuration file are as follows:
    50 {{{
    51 # Try for at most NUM seconds when building circuits. If the circuit
    52 # isn't open in that time, give up on it. (Default: 1 minute.)
    53 CircuitBuildTimeout 5
     53== TCP/IP - Optimise 2K/XP's throughput (win32) ==
     54Windows XP has a self-tuning IP stack, but it can still benefit from a little help. Using the TCP Optimiser tool from above you can tune the RWIN, SACK OPTS (rfc 2038), and tcp1323opts controlling window scaling. The tool has one button optimise. This setting is sufficient to benefit from immediate increases to Tor throughput. To increase throughput further you can try experimenting with lower values of the IP TTL (Time To Live). Values as low as 32 will work and result in improved performance.
    5455
    55 # Increase the number of guards to increase the likelihood that
    56 # you will have a few guards fast enoiugh to build these circuits.
    57 NumEntryGuards 6
    58 
    59 # Send a padding cell every N seconds to keep firewalls from closing
    60 # our connections while Tor is not in use. (Default: 5 minutes)
    61 KeepalivePeriod 60
    62 
    63 # Force Tor to consider whether to build a new circuit every NUM
    64 # seconds. (Default: 30 seconds)
    65 NewCircuitPeriod 15
    66 }}}
    67 == The proof is in the pudding, results ==
    68 With the changes made from Procedure 1 and 2, and a 2Mb connection, you can realise a sustained throughput of >100k, peaking at ~256k or more, with a ping response time of between 250 and 900ms.
    69 
    70 These figures were arrived at by using [http://speedtest.net SpeedTest.net]
    71 
    72 == Advanced Tuning for Windows ==
    73 This section has been included last for those who are technically capable.
    74 
    75 === TCPOptimizer -  2K/XP's throughput (win32) ===
    76 Windows XP has a self-tuning IP stack, but it can still benefit from a little help. Using the TCP Optimiser tool from above you can tune the RWIN, SACK OPTS (rfc 2038), and tcp1323opts controlling window scaling. The tool has one button optimise. This setting is sufficient to benefit from immediate increases to Tor throughput. To increase throughput further you can try experimenting with lower values of the IP TTL (Time To Live). Values as low as 32 will work and result in improved performance. Also try experimenting with smaller TCPWindowSizes. This setting is automatically adjusted when you move the slider marked 'Connection Speed' of the TCPOptimizer  tool.
    77 
    78 You can view your connection parameters and their effects on your connections, both with Tor and without Tor, at [http://www.dslreports.com/tweaks DSLReports]
    79 
    80 === Event ID 4226 Patcher - Remove the limit on TCP connection attempts XP SP2 (win32) ===
     56== Remove the limit on TCP connection attempts XP SP2 (win32) ==
    8157[http://www.speedguide.net/read_articles.php?id=1497 Remove the limit on TCP connection attempts] SpeedGuide.net has an interesting article detailing this restriction introduced in XP SP2. Microsoft have restricted the amount of half-open TCP/IP connections with the proviso that it would reduce the pace that worms spread. As noted by SpeedGuide, internet worms spread isotropically (multi-directionally) and so their infecton rate is exponential. As such, placing a constant (limit) on the rate of connection creation for every computer running XP SP2 will slow the rate of worms spreading (for that group of computers) but not by much. Consider the population of humans on the planet. Its over ~6 billion.
    8258
    83 Supposing all these people are running Windows XP SP2, with rate limited half-open connections. Rate limiting is set to 10 half-open connections per second. To infect the entire population of computers would take: We are assuming optimum forward infection here. In the first second we have infected 10 machines. The 2nd second to elapse will cause (10 x 10) + 10 = 110 computers to be infected. The 3rd second to elapse would cause:
     59Supposing all these people are running Windows XP SP2, with rate limited half-open connections. To infect the entire population of computers would take:
     60We are assuming optimum forward infection here. In the first second we have infected 10 machines. The 2nd second to elapse will cause (10 x 10) + 10 = 110 computers to be infected. The 3rd second to elapse would cause:
     61 ( (10 * 10) * 10 ) + (10 * 10) =  1100 computers to be infected. So the number of computers infected for every second that elapses is :
     62 computers infected = ~ 10 ^ elapsedSeconds
    8463
    85  . ( (10 x 10) x 10 ) + (10 * 10) + 10 =  1110 computers to be infected. So the number of computers infected for every second that elapses is : computers infected = ~ 10 ^ elapsedSeconds
    8664In 12 seconds, we would have 10 ^ 12 = 1 billion computers infected. Full infection occurs before 13 seconds have elapsed !
    8765
    88 This is all skewed by network topologies and routing algorithms, but they would affect a non-limited network in an identical manner. So the affect is a theoretical maximum of 13 seconds of additional notice to act against the worm. To all intents and purposes, this is useless.
     66This is all skewed by network topologies and routing algorithms, but they would affect a non-limited network in an identical manner. So the affect is a theoretical minimum of 12 seconds of additional notice to act against the worm. To all intents and purposes, this is useless.
    8967
    9068Of much more interest is the effect on ANY network that relies on many open connections, such as Tor and a host of P2P applications. The effect here is a slow down of communications, with the limit acting as the catalyst.
     
    9270Use the Event ID 4226 Patcher to mitigate against this.
    9371
     72== DNS - reducing latency ==
     73For faster DNS performance generally and with TOR(on win32 only i'm afraid) see...
     74 * [http://www.analogx.com/contents/download/network/fc.htm AnalogX - FastCache]
     75When TOR starts it will report if it is using localhost to resolve DNS addresses. When you install FastCache, it sets up a local, cached and persistent store of DNS addresses. DNS resolves cost TOR a lot in terms of latency. A large part of TOR's reduction in speed is caused by setting up the path to the Onion routers that are servicing the request. Reduce DNS latency and the time cost of setting up the TOR channels are reduced.
     76Also for all OS'es see...
     77 * [http://www.opendns.com/ OpenDNS]
    9478
    95 The following parameters must also satisfy the formula below for optimal performance.
     79== The proof is in the pudding ==
    9680
    97 ''Windows:RWIN >= Privoxy:buffer > ( Tor:ConstrainedSockSize default = 262KB )''
    98 
    99 ||Windows||in TCP Optimizer||
    100 || -- ||-- ||
    101 ||RWIN || TCPOptimizer max setting||
    102 ||Window Scaling|| On||
    103 ||TcpIP TTL || 128 (hops)||
    104 ||LANBufferSize || 65535 (bytes)||
    105 ----
    106 Reducing DNS caching time reduces the risk of an invalid DNS resolve, given Tor servers may be operating in a DHCP environment that updates the IP each time the network connects.
    107 ||Windows||registry:TCPIP service||
    108 || -- || -- ||
    109 ||DNS Cache || 36000(seconds (10 hours)) set in registry by hand, HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Dnscache\Parameters||
    110 ----
    111 Privoxy is set to be a 'straight-through' proxy server, with the toggle switch. Its buffer is reduced to below that of RWIN. This is because RWIN represents the largest TCP receive window. Its value is chosen to be above Tor default socks size = 252KB
    112 ||Privoxy||config.txt||
    113 || -- || -- ||
    114 ||Privoxy:buffer || 265 (KB)||
    115 ||toggle || 0||
    116 
    117 CategoryHowTos
     81With the changes made from Procedure 2, you can realise a sustained throughput of >100k, peaking at ~200k or more. These figures are based on the highest TOR bandwidth settings (>1.5mbps), through a 2mb connection. You will also experience much lower DNS latency in general. TOR at version 0.1.2.x uses an Asynchronous DNS resolver, the DNS tips above positively affect TOR traffic.