Images aren't loaded as high priority

[mbehzad]

Hi Patrick,
when I run the tests with the cloudflare image from the readme, the last images aren't loaded earlier than the previous images.

When inspecting the dependency graph, the last two images have the same weight (147) as the other ones and depend on the streams of the previous images. https://www.webpagetest.org/result/221211_AiDcVH_97K/1/details/#waterfall_view_step1
When slightly modifying the test to set the fetchPriority property to high for the last two images, then i see that their weights change to 220 and are children of the root stream. But still the requests get a late response:

Which I wasn't expecting due to Cloudflare being listed as supporting h2 (re)prioritization.

Did something change in Chrome and Cloudflare in the meantime? Or am i interpreting the results wrong?
Cheers
Mehran

[pmeenan]

Might need a slightly faster connection profile or try the initial test again. The narrow yellow bars mean that Chrome held the requests back on the client so the higher-priority ones were sent earlier on the wire (requests 14 and 23 with no yellow line).

Even then, the high-priority images appear to be more interleaved with the low priority images than you'd expect.

Cloudflare has their own prioritization layer on top of HTTP/2 priorities that may fail to reprioritize but that shouldn't affect the fetchpriority case where it goes out with a higher weight right away.

It's probably worth pinging them to take a look in case they are working on H3 priorities and something changed unexpectedly.