[Foundation-l] [Internal-l] Relocation Announcement

Anthony wikimail at inbox.org
Mon Sep 24 18:35:13 UTC 2007


On 9/24/07, Mark Bergsma <mark at wikimedia.org> wrote:
> Anthony wrote:
> > On 9/24/07, Gregory Maxwell <gmaxwell at gmail.com> wrote:
> >> A lot of things can be improved, but we can't increase the speed of
> >> light.
> >>
> > It only takes light about 1/100th of a second to travel across the
> > atlantic ocean.  Speed of light isn't the bottleneck.
>
> It takes packets about 70ms to travel across the atlantic ocean and
> back, determined by the speed of light through fiber. Since a typical
> HTTP request requires a few of these round trips, the speed of light
> *is* the bottleneck.
>
http://royal.pingdom.com/?p=143

My figure was off.  But 1.215 seconds still is nowhere near the
theoretical maximum (about 133 milliseconds anywhere in the world).
I'd say HTTP is the bigger bottleneck, with router forwarding probably
equaling about the same as the speed of light.  (Even then, it's not a
matter of physical distance.  I live in Tampa, and I just got 139ms
pings, although a traceroute I just ran shows the packets going
through Virginia).

Anyway, my comment wasn't meant to be practical for the foundations
particular problem.  Sorry about that.

> And that's just one HTTP request. It would be way worse if we sent all
> the very many DB/memcached/DNS/etc lookups necessary to build a single
> wiki page over the atlantic...
>
If you didn't pipeline them.  But why in the world would you do that?



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