[tor-bugs] #21394 [Core Tor/Tor]: connection timeouts are affecting Tor Browser usability
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Sat Feb 4 03:51:50 UTC 2017
#21394: connection timeouts are affecting Tor Browser usability
--------------------------------------------+---------------------
Reporter: arthuredelstein | Owner:
Type: defect | Status: new
Priority: Medium | Milestone:
Component: Core Tor/Tor | Version:
Severity: Normal | Resolution:
Keywords: tbb-performance, tbb-usability | Actual Points:
Parent ID: | Points:
Reviewer: | Sponsor:
--------------------------------------------+---------------------
Description changed by arthuredelstein:
Old description:
> I have spent some time watching circuit and stream events while
> connecting to different sites. I telnet into tor's config port using the
> following command (using ts to give time stamps):
> {{{
> telnet localhost 9151 | ts
> }}}
> I open the browser console and get the tor password by entering
> `m_tb_control_pass`
> And then I paste the result like this:
> `authenticate [value of m_tb_control_pass]`
> Finally I enter
> `setevents circ stream`.
>
> What I have noticed is that a significant fraction of new site
> connections result in at least 1 timeout of 10 seconds. (Tor Browser's
> CircuitStreamTimeout is set to 0, which results in a timeout equal to
> MIN_CIRCUIT_STREAM_TIMEOUT, or 10 seconds.) Here's what a timeout looks
> like:
> {{{
> Feb 03 19:00:03 650 STREAM 868 NEW 0 people.torproject.org:443
> SOURCE_ADDR=127.0.0.1:50318 PURPOSE=USER
> Feb 03 19:00:03 650 CIRC 149 LAUNCHED BUILD_FLAGS=NEED_CAPACITY
> PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
> Feb 03 19:00:03 650 CIRC 149 EXTENDED [...] BUILD_FLAGS=NEED_CAPACITY
> PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
> SOCKS_USERNAME="torproject.org"
> SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
> Feb 03 19:00:04 650 CIRC 149 EXTENDED [...] BUILD_FLAGS=NEED_CAPACITY
> PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
> SOCKS_USERNAME="torproject.org"
> SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
> Feb 03 19:00:04 650 CIRC 149 EXTENDED [...] BUILD_FLAGS=NEED_CAPACITY
> PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
> SOCKS_USERNAME="torproject.org"
> SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
> Feb 03 19:00:04 650 CIRC 149 BUILT [...] BUILD_FLAGS=NEED_CAPACITY
> PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
> SOCKS_USERNAME="torproject.org"
> SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
> Feb 03 19:00:04 650 STREAM 868 SENTCONNECT 149 people.torproject.org:443
> [...]
> Feb 03 19:00:14 650 STREAM 868 DETACHED 149 people.torproject.org:443
> REASON=TIMEOUT
> Feb 03 19:00:14 650 CIRC 150 LAUNCHED BUILD_FLAGS=NEED_CAPACITY
> PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:14.588714
> }}}
>
> I did an experiment where I connected to
> people.torproject.org/~arthuredelstein (a page with hardly any content)
> and then repeatedly selected "New Tor Circuit for this Site" 50 times.
>
> Here are the results for 50 reloads. Each digit represents the number of
> 10-second stream timeouts observed before a given connection succeeded.
> 20020000000000000000002010000000000001000100000103
>
> In other words 8 out of 50 connections showed a timeout. And
> interestingly, four of these connections exhibited a double or triple
> timeout (20 or 30 seconds delay).
>
> I think this may be a big part of the perception of Tor Browser as
> "slow". Actual loading of pages doesn't seem drastically slow to me, and
> once I have successfully connected to a new site, following links to
> other pages on the same site (i.e., the same circuit) is usually
> acceptable.
>
> (I also did another quick test on another site and 5/25 connections had
> at least 1 timeout.)
>
> So here are some questions for further investigation:
> * Why are there so many timeouts? Are any of these timeouts due to silent
> errors in a Tor node? (If such errors could be reported, maybe we could
> avoid the long timeout.)
> * What's the reason for MIN_CIRCUIT_STREAM_TIMEOUT being 10 seconds?
> Would it do any harm to make this shorter, say 5 seconds or 2 seconds?
> * So many double or triple timeouts are suspicious, because they are
> using different circuits. Could this mean the connection error is caused
> by the client or guard?
New description:
I have spent some time watching circuit and stream events while connecting
to different sites. I telnet into tor's config port using the following
command (using ts to give time stamps):
{{{
telnet localhost 9151 | ts
}}}
I open the browser console and get the tor password by entering
`m_tb_control_pass`
And then I paste the result like this:
`authenticate [value of m_tb_control_pass]`
Finally I enter
`setevents circ stream`.
What I have noticed is that a significant fraction of new site connections
result in at least 1 timeout of 10 seconds. (Tor Browser's
CircuitStreamTimeout is set to 0, which results in a timeout equal to
MIN_CIRCUIT_STREAM_TIMEOUT, or 10 seconds.) Here's what a timeout looks
like:
{{{
Feb 03 19:00:03 650 STREAM 868 NEW 0 people.torproject.org:443
SOURCE_ADDR=127.0.0.1:50318 PURPOSE=USER
Feb 03 19:00:03 650 CIRC 149 LAUNCHED BUILD_FLAGS=NEED_CAPACITY
PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
Feb 03 19:00:03 650 CIRC 149 EXTENDED [...] BUILD_FLAGS=NEED_CAPACITY
PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
SOCKS_USERNAME="torproject.org"
SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
Feb 03 19:00:04 650 CIRC 149 EXTENDED [...] BUILD_FLAGS=NEED_CAPACITY
PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
SOCKS_USERNAME="torproject.org"
SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
Feb 03 19:00:04 650 CIRC 149 EXTENDED [...] BUILD_FLAGS=NEED_CAPACITY
PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
SOCKS_USERNAME="torproject.org"
SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
Feb 03 19:00:04 650 CIRC 149 BUILT [...] BUILD_FLAGS=NEED_CAPACITY
PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:03.738597
SOCKS_USERNAME="torproject.org"
SOCKS_PASSWORD="7d8ea4ccf4ba6345846e0fccacd4d941"
Feb 03 19:00:04 650 STREAM 868 SENTCONNECT 149 people.torproject.org:443
[...]
Feb 03 19:00:14 650 STREAM 868 DETACHED 149 people.torproject.org:443
REASON=TIMEOUT
Feb 03 19:00:14 650 CIRC 150 LAUNCHED BUILD_FLAGS=NEED_CAPACITY
PURPOSE=GENERAL TIME_CREATED=2017-02-04T03:00:14.588714
}}}
I did an experiment where I connected to
people.torproject.org/~arthuredelstein (a page with hardly any content)
and then repeatedly selected "New Tor Circuit for this Site" 50 times.
Here are the results for 50 reloads. Each digit represents the number of
10-second stream timeouts observed before a given connection succeeded.
20020000000000000000002010000000000001000100000103
In other words 8 out of 50 connections showed a timeout. And
interestingly, four of these connections exhibited a double or triple
timeout (20 or 30 seconds delay).
I think this may be a big part of the perception of Tor Browser as "slow".
Actual loading of pages doesn't seem drastically slow to me, and once I
have successfully connected to a new site, following links to other pages
on the same site (i.e., the same circuit) is usually acceptable.
(I also did another quick test on another site and 5/25 connections had at
least 1 timeout.)
So here are some questions for further investigation:
* Why are there so many timeouts? Are any of these timeouts due to silent
errors in a Tor node? (If such errors could be reported, maybe we could
avoid the long timeout.)
* What's the reason for MIN_CIRCUIT_STREAM_TIMEOUT being 10 seconds? Would
it do any harm to make this shorter, say 5 seconds or 2 seconds?
* So many double or triple timeouts are suspicious, because each timeout
is reported for a different circuit. Could this mean the connection error
is caused by the client or guard rather than a connection failure at the
exit node?
--
--
Ticket URL: <https://trac.torproject.org/projects/tor/ticket/21394#comment:2>
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