On Tue, Nov 5, 2013 at 4:56 PM, Ori Livneh [email protected] wrote:
On Mon, Nov 4, 2013 at 4:50 AM, Mark A. Hershberger [email protected] wrote:
Hrm... I should probably go ask them about that. But I'm curious about your perspective and to see if we have any information on the bandwidth available to various users.
There is some, but not enough for us to know in advance what sort of impact this will have. But Aaron Hafaker and I are working on it, and we are going to be rigorous about measuring it, and we will report back.
We ran a controlled test and found that module storage reduced page load times by 156 ms, on average. Aaron has some data available at < https://meta.wikimedia.org/wiki/Research:Module_storage_performance%3E, but we still need to write several sections. The size of the effect is substantially smaller on mobile, for some reason, which is surprising. We hope to make the dataset public soon.
156ms shaved off of 90% of page views is pretty nice. http://perspectives.mvdirona.com/2009/10/31/TheCostOfLatency.aspx is worth reading for context and scale:
"This conclusion may be surprising -- people notice a half second delay? -- but we had a similar experience at Amazon.com. In A/B tests, we tried delaying the page in increments of 100 milliseconds and found that even very small delays would result in substantial and costly drops in revenue."
We'll gradually enable module storage on all Wikimedia wikis over the course of the next week or two.