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由 Chris Wilson 提交于
Some users require that when a master batch is executed on one particular engine, a companion batch is run simultaneously on a specific slave engine. For this purpose, we introduce virtual engine bonding, allowing maps of master:slaves to be constructed to constrain which physical engines a virtual engine may select given a fence on a master engine. For the moment, we continue to ignore the issue of preemption deferring the master request for later. Ideally, we would like to then also remove the slave and run something else rather than have it stall the pipeline. With load balancing, we should be able to move workload around it, but there is a similar stall on the master pipeline while it may wait for the slave to be executed. At the cost of more latency for the bonded request, it may be interesting to launch both on their engines in lockstep. (Bubbles abound.) Opens: Also what about bonding an engine as its own master? It doesn't break anything internally, so allow the silliness. v2: Emancipate the bonds v3: Couple in delayed scheduling for the selftests v4: Handle invalid mutually exclusive bonding v5: Mention what the uapi does v6: s/nbond/num_bonds/ Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com> Reviewed-by: NTvrtko Ursulin <tvrtko.ursulin@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20190521211134.16117-9-chris@chris-wilson.co.uk
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