| DM is like GM, but multithreaded. It doesn't do everything GM does. | |
| DM's design is based around Tasks and a TaskRunner. | |
| A Task represents an independent unit of work that might fail. We make a task | |
| for each GM/configuration pair we want to run. Tasks can kick off new tasks | |
| themselves. For example, a CpuTask can kick off a ReplayTask to make sure | |
| recording and playing back an SkPicture gives the same result as direct | |
| rendering. | |
| The TaskRunner runs all tasks on one of two threadpools, whose sizes are | |
| configurable by --cpuThreads and --gpuThreads. Ideally we'd run these on a | |
| single threadpool but it can swamp the GPU if we shove too much work into it at | |
| once. --cpuThreads defaults to the number of cores on the machine. | |
| --gpuThreads defaults to 1, but you may find 2 or 4 runs a little faster. | |
| So the main flow of DM is: | |
| for each GM: | |
| for each configuration: | |
| kick off a new task | |
| < tasks run, maybe fail, and maybe kick off new tasks > | |
| wait for all tasks to finish | |
| report failures | |