Re: expected substantial and measurable improvements in WG charter

[Willy Tarreau <[e-mail]>]

Hi Mark, Larry,

On Thu, Mar 12, 2015 at 02:04:54PM +1100, Mark Nottingham wrote:
> > That???s not the same as consensus as to whether HTTP/2 meets the ???It is
> > expected that??? list in the charter. In particular, the charter expects
> > HTTP/2 to substantially and measurably improve end-user perceived latency
> > in most cases.  But it seems there mostly agreement (not consensus to the
> > contrary) that to substantially improve end-user perceived latency in
> > ???most cases???, you not only need HTTP/2 but also a good deal of mainly
> > undisclosed magic. And that quite a few sites will see worse performance if
> > they merely replace HTTP/1.1 with HTTP/2 (with the necessary shift to TLS).
> 
> That's not the agreement that I see at all. Most people with operational
> experience of the protocol have said that one can expect a 5-15% end-user
> perceived performance benefit "out of the box" with a reasonable
> implementation, and substantially more with some tweaking (e.g., removing
> spriting/inlining/sharding/concatenation, adjusting prioritisation algorithms
> and thinking about server push). Those numbers don't hold for every site on
> every network, but that's the nature of the Internet.

I think there is no reason to worry much on the server side. In practice,
it will be for every web site just like when admins try to enable HTTPS :
some will not observe any cost change because the application's resources
usage is so high that TLS is very cheap, some will observe a significant
degradation (resource usage or extra requests due to proxies not caching
contents anymore) and will have to decide whether it's for them or not
(just like when switching to HTTPS), some will see a significant
improvement and will want to evangelize the new protocol all around them.

Given what we've seen with sites switching to HTTPS, I think that most
deployments will experience a small difference in either direction and
will consider that it's worth leaving it enabled at least to embrace
upcoming technology improvements in various products (eg: server push).

So I think we should wait and observe, even before trying to fix anything.
We all know there's a lot of room for improvement in this protocol and
possibly we've all missed much more important parts that non-wg users
will loudly complain about, so let's calmly wait for this feedback before
declaring any difficulty, failure or whatever.

Willy