[tor-dev] Starting work on hidden services

[Qingping Hou]

On 03/27/2014 03:25 PM, Helder Ribeiro wrote:
> Hi Qingping, thanks for the help! Answer below:
> 
> 
> On Tue, Mar 25, 2014 at 2:44 AM, Qingping Hou <dave2008713 at gmail.com> wrote:
> 
>> If you decided to work on profiling hidden service, I would suggest you
>> take a
>> look at chutney[1] and shadow[2]. Torperf is not under active maintenance
>> anymore and it can be easily replaced by chutney.
>>
> 
> Thanks for the pointers. I'm still not very clear on what each of shadow,
> chutney, experimentor, torperf or even oprofile should be used for. I'm
> guessing chutney/oprofile (maybe toperf, originally, too?) are more useful
> for profiling processes, with less control over what happens in the
> network, and shadow/experimentor are more useful for network-level
> simulation. Please correct me if I'm wrong.
> 
> 

Correct.

>>
>> A fully automated hidden service profiling tool will be very handy. As the
>> community is currently designing next generation hidden service protocol,
>> such
>> tool will help developers evaluate different designs and implementations.
>>
> 
> Great! Do you know what kinds of things are most useful to measure first?
> Is it more useful at this point to:
> 1. measure time spent on functions within a process, to see if there's
> anything taking up too much time, for example, at the hidden service's OP
> during the handshake; or
> 2. simulate load on a hidden service and see how request response time
> climbs with number of clients, etc.?
> 

I would say 2 is better. I have done some initial profiling on low load HS and
found that time spent on functions (i.e. computation) is negligible compared the
time spent on creating circuits and cell transmitting.