Re: kernel.org mirroring (Re: [GIT PULL] MMC update)

From: Martin Langhoff <martin.langhoff@gmail.com>
Date: Dec 9, 2006, 05:34 UTC
Message-ID: <46a038f90612082134x38be9c8dgca6fe60c087bf100@mail.gmail.com>
In-Reply-To: <457A44ED.4080606@zytor.com>

On 12/9/06, H. Peter Anvin <hpa@zytor.com> wrote:

Show 6 quoted lines

> Martin Langhoff wrote:
> > I posted separately about those. And I've been mulling about whether
> > the thundering herd is really such a big problem that we need to
> > address it head-on.
>
> Uhm... yes it is.

Got some more info, discussion points or links to stuff I should read to appreciate why that is? I am trying to articulate why I consider it is not a high-payoff task, as well as describing how to tackle it.

To recap, the reasons it is not high payoff is that:

 - the main benefit comes from being cacheable and able to revalidate
the cache cheaply (with the ETags-based strategy discussed above)
 - highly distributed caches/proxies means we'll seldom see a true
cold cache situation
 - we have a huge set of URLs which are seldom hit, and will never see
a thundering anything
 - we have a tiny set of very popular URLs that are the key target for
the thundering herd - (projects page, summary page, shortlog, fulllog)
- but those are in the clear as soon as the caches are populated

Why do we have to take it head-on? :-)