In 2014 we found that 60% of requests for static resources resulted in a 304. Since content addressed URLs never change, this means there was an opportunity to optimize away 60% of static resource requests.
於是他們找出原因後,發現 Google Chrome 只要 POST 後的頁面都會 revalidate:
A piece of code in Chrome hinted at the answer to our question. This line of code listed a few reasons, including reload, for why Chrome might ask to revalidate resources on a page. For example, we found that Chrome would revalidate all resources on pages that were loaded from making a POST request.
然後在討論後認為這個行為不必要,就修掉了,可以看到降了非常多:
We worked with Chrome product managers and engineers and determined that this behavior was unique to Chrome and unnecessary. After fixing this, Chrome went from having 63% of its requests being conditional to 24% of them being conditional.
The fact that the percentage of conditional requests from Chrome was still higher than other browsers seemed to indicate that we still had some opportunity here. We started looking into reloads and discovered that Chrome was treating same URL navigations as reloads while other browsers weren't.
不過這次推出修正後發現沒有大改變:(拿 production 測試 XDDD)
Chrome fixed the same URL behavior, but we didn't see a huge metric change. We began to discuss changing the behavior of the reload button with the Chrome team.
There was some debate about what to do, and we proposed a compromise where resources with a long max-age would never get revalidated, but that for resources with a shorter max-age the old behavior would apply. The Chrome team thought about this and decided to apply the change for all cached resources, not just the long-lived ones.
In a nutshell, BBR creates an explicit model of the network pipe by sequentially probing the bottleneck bandwidth and RTT. On the arrival of each ACK, BBR derives the current delivery rate of the last round trip, and feeds it through a windowed max-filter to estimate the bottleneck bandwidth. Conversely it uses a windowed min-filter to estimate the round trip propagation delay. The max-filtered bandwidth and min-filtered RTT estimates form BBR's model of the network pipe.
But there's a better way: for a small sum, you can just set up an offshore shell company, direct it to sue a Chinese company you own, throw the lawsuit, and then, oh well, I guess there's nothing for it but to send a bunch of cash to your shell company, exempted from export controls, in the form of court-ordered damages.
Versions of PuTTY and pterm between 0.54 and 0.65 inclusive have a potentially memory-corrupting integer overflow in the handling of the ECH (erase characters) control sequence in the terminal emulator.