[tor-reports] dgoulet's November 2014
dgoulet at ev0ke.net
Sun Nov 30 15:51:01 UTC 2014
# Status report for November 2014
My contract started on November 1st with most of my time on SponsorR.
I went for hidden service code spelunking at the beginning of the month
to get a better understanding of this subsystem.
- Setup an experiment to profile the performance of an HS service. Basic
IRC server and I fired one hundred client connections through
different circuits and used "perf" profiling on the service side.
Posted an update on #8902 for this with the results here:
For the needed optimization of this work: #13738, #13739
- Help draft a proposal for collecting HS statistics with asn and
karsten that has been split into a proposal made by asn/karsten to
collect HS usage on the real Tor network. The other part will become a
tech report soon (karsten work).
Reference: #13509, #13792
- Applied Roger's patch for collecting some basic HS stats (#13195) on
my fast relay to investiguate #13287 (Investigate mysterious 24-hour
lump in hsdir desc fetches).
Modified it a bit to log the hashed service descriptor that was being
fetched over and over again thus giving us a possible answer:
- Went to Boston for a full week to collaborate with nickm on lots of
areas of the Tor code base. Useful mentoring and guidance.
- I've started instrumenting the HS subsystem with "trace events" on
which we can hook a user space tracer (like DTrace, SystempTap,
LTTng). The goal is to have a tracing framework, *ONLY* for private
network and should NEVER be deployed in production, that allows us to
easily and efficiently gather low level information in order to build
a performance baseline of the whole HS system.
I've hooked LTTng user space tracer to the instrumentation. Work can
be found here (#13802):
It's based on 0.2.5 and the reason is to be able to measure both 0.2.5
and 0.2.6 for comparison.
- Setup a Chutney network that supports an HS service. I ran an
experiment to measure HS system timings. For that, I used the above
LTTng branch with an analysis script of the trace.
Preliminary results on Introduction Point build time for HS service
(for which I'll post a much more detailed report and documentation
later on along with the tools needed).
0.2.5 --> https://people.torproject.org/~dgoulet/ip.png
0.2.6 --> https://people.torproject.org/~dgoulet/ip-026.png
- Ticket work:
#8902 - Rumors that hidden services have trouble scaling to 100
#13664 - Potential issue with rend cache object when intro points
falls to 0.
#13739 - Optimize the functions called in
#13790 - Refactor and add comments to new_route_len()
#13667 - Prevent port scanning of hidden services
#13698 - Wrong failure report when closing parallel intro points
#13287 - Investigate mysterious 24-hour lump in hsdir desc fetches
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