[Impeller] Use the IO context for OpenGL program setup#31
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xiaowei-guan wants to merge 7 commits intoflutter-tizen:flutter-3.41.4from
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[Impeller] Use the IO context for OpenGL program setup#31xiaowei-guan wants to merge 7 commits intoflutter-tizen:flutter-3.41.4from
xiaowei-guan wants to merge 7 commits intoflutter-tizen:flutter-3.41.4from
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…of waiting. (flutter#180022) Also, removes "lazy shader mode" and re-enables eager PSO pre-flight. Impeller eagerly sets up the entire set of pipeline state objects (PSOs) it may need during renderer setup. This works fine on mid to high-end devices as the setup completes well before the first frame is rendered. However on low-end devices, not all PSOs may be ready before the first frame is rendered. Low-end device usually don't have as much available concurrency and are slower to boot. On these devices, the rendering thread had to wait for the background compile job to be completed. It was also observed that the relatively higher priority render thread was waiting on a background thread to finish a PSO compile job. The PSO compile job could also be stuck behind another job that was not immediately needed. This made the situation on low end devices less than ideal. To ameliorate this situation, a stop-gap was introduced called "lazy shader mode". This disabled PSO pre-flight entirely and only dispatched jobs when they were needed. This ameliorated somewhat the issue of unneeded jobs blocking the eagerly needed job but the other issues remained. It also meant that one could expect jank the first time a new PSO was needed. This mode was not widely used or advertised. In this patch, the lazy shader mode has been entirely removed and eager PSO pre-flight is the default in all configurations. Pipeline compile jobs are now handled by a separate compile queue. This queue operates like a transparent concurrent worker pool job dispatcher in the usual case. However, when the pipeline for a specific descriptor is needed, instead of waiting for the job to complete, the queue allows the job for that descriptor to skip to the head of the queue and be performed on the calling thread. This effectively make the calling thread do the job instead of waiting. Another nice side effect of this behavior is that the higher priority thread is now doing the job it was previously waiting on. This fixes all issues on lower end devices except one. During eager pre-flight, it would still be better if PSO compile jobs for that were somehow divined to be needed first were towards the front of the pre-flight queue. After all, only a handful of rendering features account for the majority of rendering operations. A future augmentation to the compile queue would be to allow higher prioritization of more widely used pipeline compile jobs as instrumented in flutter#176660. This task is tracked in flutter#176665. This patch only wires up the compile queue for Vulkan. flutter#176657 tracks doing the same for OpenGL. The efficacy of the re-prioritizations can be traced using the PrioritiesElevated trace counter. On higher end devices, there should be zero of these. Fixes flutter#176656 Fixes flutter#176663 Fixes flutter#176658
Because IO thread is the owner of resource context, pipeline library gles can load resource by IO thread.
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