Visualizing SPDY vs HTTP

When we were developing SPDY, we wanted to know if SPDY was always faster or just sometimes faster than HTTP. The following chart is what convinced us that SPDY is indeed almost always faster. I didn’t publish this at that time because I didn’t like looking at web performance as a single number. “Is it faster” includes many variables, such as the network simulated (bandwidth & latency), the packet loss rate, the content chosen, and the measurement (total PLT, first PLT, second PLT, or time-to-first-render). You’d really want a whole stack of these charts, rather than just a single combination.

What I like about this chart is how easy it is to compare two protocols. If the two protocols are identical in performance, all points would be on the midline (red). If one protocol is slower, then the points will fall closer to that axis.

SPDY vs HTTP PLT

Notes about this test:

  • Used a static copy of the Alexa Top-300 websites (excluded porn sites), full content, unchanged
  • Simulated 2Mbps download, 386Kbps upload, 100ms RTT, 0% packet loss
  • No SSL
  • The average speedup was ~40% on this test
  • This test predates CWND changes in the kernel
  • Server was linux, client was chrome on Windows 7

I will donate $1,000,000 to the US Govt This Year

The US debt is a big problem (currently ~$16T, or about ~$50K per person). I’m willing to do my share to help pay it off. To do this, I need the government to commit to a sustainable plan so that I’m not just throwing good money after bad.

Thus I make this promise:

If Washington can make spending match tax receipts, I will donate an extra $1,000,000 to the USA to help pay down the debt.