Re: hardware acceleration available for Tor ? On FreeBSD ?

[Scott Bennett <bennett@xxxxxxxxxx>]

     On Mon, 12 Oct 2009 20:19:39 +0000 (UTC) John Case <case@xxxxxxxxxxxxxxxx>
wrote:
     Most of your questions below I can offer no information about, but I'll
answer the ones I can.

>(replying to my own post to pass on what I've learned in the last day)
>
>
>On Mon, 12 Oct 2009, John Case wrote:
>
>> I can see notes like this in the changelog:
>>
>>
>> Solve a bug that kept hardware crypto acceleration from getting
>> enabled when accounting was turned on. Fixes bug 907. Bugfix on
>> 0.0.9pre6.
>
>
>>From irc:
>
>jcase: be sure to use 0.2.2.x:
>
>... as it appears that only that release and newer can be assured of 
>proper "HardwareAccel" support ...
>
>- New AccelName and AccelDir options add support for dynamic OpenSSL 
>hardware crypto acceleration engines.
>
>
>> I would like hardware acceleration for my nodes.  What part or parts are 
>> known to work well with FreeBSD ?
>
>
>While there are several drivers in FreeBSD, my own impression is that the 
>ubsec driver is the right choice, currently, as it drives a long list of 
>broadcom-based PCI cards, most notably the BCM5821, which is the chip 
>driving the "Sun Crypto 1000" which can be had cheaply on ebay, and the 
>BCM5825, which is the latest and greatest of these cards.
>
>One caveat with the BCM5821 or the Sun Crypto 1000 is that not all of them 
>support AES - I can't tell for sure, but it looks like AES support was 
>added after the fact, and it depends on firmware version.  The BCM5825 is 
>a safer bet if you're buying off of ebay, etc., but is more expensive.
>
>Everything I have mentioned here appears to be pci64/pci-X, rather than 
>pci-e.
>
>
>> Any comments on the effectiveness of these parts, and the likelihood that 
>> they will actually allow a greater network throughput on the same underlying 
>> cpu(s) and memory, is appreciated.
>>
>> I have been under the impression that memory is more of a limiting factor 
>> than cpu - with some estimates being 750-ish megabytes of ram per 10mbits/s. 
>> I am unsure whether hardware crypto acceleration will decrease this memory 
>> load, or simply decrease cpu load.
>
>
>I got these loose numbers off of an archived list discussion, but it 
>appears to be false.  Again from irc:
>
>"tor is actually cpu-bound rather than ram-bound on the fast relays i 
>think you should be able to push 10MB/s in 1G of ram"
>
>So crypto-acceleration appears to be useful.
>
     The symmetric-key processing is very fast and takes up little CPU time.
The apparent hangup on the high-rate relays is the asymmetric-key processing
(i.e., onion-skin encrypting/decrypting).  FWIW, when I was running a relay,
it could be running at rates over 300 KB/s while using less than 1% of the
CPU when it was simply passing cells back and forth among the various
connections.  When new onion skins came in to be decrypted was when tor would
suddenly use much more CPU time for a moment or two.
>
>Unanswered questions:
>
>
>- how painful is actual integration?  Just because the driver is there and 
>those options are available in Tor doesn't mean it will be a snap.  Word 
>on the street is that "coderman" has actually done this ... comments ?
>
>- Is the BCM5825 the most powerful solution that can be easily made to 
>work on FreeBSD ?  The soekris cards are much less powerful, the SafeNet 
>1741 has a lower throughput and the 1742/1746 parts are not listed on the 
>FreeBSD HCL.  Not sure where the Sun Crypto 6000 lies on this continuum, 
>but it appears to NOT be a broadcom based card.
>
>- Is anyone _actually_ testing Tor, and more specifically, hardware crypto 
>acceleration of Tor, in high speed (gigabit) test environments ?
>
>- Is anyone _actually_ performing SSL operations in CUDA using GPUs, and 
>if not, how much of my free time and mindshare over the next year will be 
>spent on that fascinating question ?
>
     If they are, they're most likely not doing it under FreeBSD.  The last
time I checked, there was still no support for either CUDA (nVidia) or
Streams (ATi) under FreeBSD. :-(
>
>I'll be ordering some parts and setting up some rudimentary tests in the 
>next few months, but any comments or suggestions or war stories would be 
>very helpful.


                                  Scott Bennett, Comm. ASMELG, CFIAG
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