> 1. priority dependencies: streams with lower prio, but depending on a high > level stream, inherit this priority. This would make all preloads > *together* have the same prio as page B. Last I knew, chrome did no > dependencies. Were these resources PUSHed by the server? >
Not PUSHed; they were requested by the browser upon A's onLoad using the ' link rel=”prefetch” ' directive in HTML A's <head>. Right, I forgot to add this in the description: Chrome's log shows the priorities/dependencies as follows: HTML A : stream_id=1, parent_stream=0, weight=256 1st Prefetched image : stream_id=3, parent_stream=0, weight=110 2nd Prefetched image : stream_id=5, parent_stream=3, weight=110 3nd Prefetched image : stream_id=7, parent_stream=5, weight=110 ... 8th Prefetched image : stream_id=17, parent_stream=15, weight=110 HTML B : stream_id=19, parent_stream=0, weight=256 So my understanding was that the dependencies looked reasonable, i.e. the prefetched objects form a separate lower priority chain starting at the root and as such should not block anything with higher prio with the same parent (0). Am I reading this correctly? > 2. mod_http2 is, in its current implementation, very eager to fill the > core network buffers. That means a lot of frames have already been > pre-packaged for sending before page B becomes ready to sent. These are > then not pre-empted by page B, but will be sent first. > > If you are willing to test a github beta of the module, I might find the > time next week to tweak the behaviour in 2) and you could verify the > benefits in your setup. I will not promise anything, though. > This was my (as well as a few Chrome devs') guess, especially considering that HTML B is not blocked behind the prefetched images (in fact not even blocked by completing any single one of them: the images are sent serially and HTML B is correctly interleaved between frames of one of those images - it just doesn't seem to happen as quickly as it could have (~500ms earlier, in this particular case) ). I'd be really interested in repeating the experiment with a tweaked version of the module. Please feel free to let me know if/how I can help. Thanks, Kyriakos > > -Stefan > > > > >
