[Python-Dev] Summing up

geremy condra debatem1 at gmail.com
Wed May 19 18:27:36 CEST 2010


On Tue, May 18, 2010 at 4:10 PM, Antoine Pitrou <solipsis at pitrou.net> wrote:
> On Tue, 18 May 2010 21:43:30 +0200

<snip>

> Regardless of the fact that apparently noone reported it in real-world
> conditions, we *could* decide that the issue needs fixing. If we
> decide so, Nir's approach is the most rigorous one: it tries to fix
> the problem thoroughly, rather than graft an additional heuristic. Nir
> also has tested his patch on a variety of machines, more so than Dave
> and I did with our own patches; he is obviously willing to go forward.
>
> Right now, there are two problems with Nir's proposal:
>
> - first, what Nick said: the difficulty of having reliable
>  high-precision cross-platform time sources, which are necessary for
>  the BFS algorithm. Ironically, timestamp counters have their own
>  problems on multi-core machines (they can go out of sync between
>  CPUs). gettimeofday() and clock_gettime() may be precise enough on
>  most Unices, though.
>
> - second, the BFS algorithm is not that well-studied, since AFAIK it
>  was refused for inclusion in the Linux kernel; someone in the
>  python-dev community would therefore have to make sense of, and
>  evaluate, its heuristic.

I don't have the expertise to do this, but I'll be playing with the
patch over the next few weeks, so if there's a specific piece of
data you want, let me know.

Geremy Condra


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