On 07.11.2017 15:29, Mikko Perttunen wrote: > On 05.11.2017 19:43, Dmitry Osipenko wrote: >> On 05.11.2017 14:01, Mikko Perttunen wrote: >>> In the traditional channel allocation model, a single hardware channel >>> was allocated for each client. This is simple from an implementation >>> perspective but prevents use of hardware scheduling. >>> >>> This patch implements a channel allocation model where when a user >>> submits a job for a context, a hardware channel is allocated for >>> that context. The same channel is kept for as long as there are >>> incomplete jobs for that context. This way we can use hardware >>> scheduling and channel isolation between userspace processes, but >>> also prevent idling contexts from taking up hardware resources. >>> >> >> The dynamic channels resources (pushbuf) allocation is very expensive, >> neglecting all benefits that this model should bring at least in non-IOMMU case. >> We could have statically preallocated channels resources or defer resources >> freeing. > > This is true. I'll try to figure out a nice way to keep the pushbuf allocations. One variant could be to have all channels resources statically preallocated in a non-IOMMU case because CMA is expensive. Then you should measure the allocations impact in a case of IOMMU allocations and if it is significant, maybe implement Host1x PM autosuspend, releasing all channels when Host1x become idle. I think the above should be efficient and easy to implement. -- To unsubscribe from this list: send the line "unsubscribe linux-tegra" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
