[tor-dev] Tor BSD underperformance (was [Tor-BSD] Recognizing Randomness Exhaustion)

[Yawning Angel]

On Thu, 1 Jan 2015 14:19:08 +1100
teor <teor2345 at gmail.com> wrote:
> On 1 Jan 2015, at 07:39 , Greg Troxel <gdt at lexort.com> wrote:
> 
> Tor 0.2.6.2-alpha (just in the process of being released) has some
> changes to queuing behaviour using the KIST algorithm. 
> 
> The KIST algorithm keeps the queues inside tor, and makes
> prioritisation decisions from there, rather than writing as much as
> possible to the OS TCP queues. I'm not sure how functional it is on
> *BSDs, but Nick Mathewson should be able to comment on that. (I've
> cc'd tor-dev and Nick.)

I don't think we merged that branch yet, since it's not ready for
general use.  Additionally, it's not currently functional on the
*BSDs.  The KIST code last I checked only is used under Linux.  While
the full portability story is in #12890 it looks roughly like:

 * Linux - Supported.
 * Windows - Possible, needs code in tor.
 * Darwin - Possible, uses interfaces marked as undocumented/internal.
 * FreeBSD - Requires a trivial kernel patch (interface is there,
   information exposed is incomplete).
 * Other BSDs - Requires a kernel patch, which is more involved than
   the FreeBSD one (implementing the required interface vs exposing
   more information).  The patch is still trivial for anyone that's
   familiar with the TCP/IP code.

I don't think we should be in the business of maintaining kernel
patches either, so I'm not sure what the right thing to do would be for
non-Darwin *BSD.

Regards,

-- 
Yawning Angel
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