On Fri, May 07, 2021 at 11:33:46AM -0400, Kenny Ho wrote: > On Fri, May 7, 2021 at 4:59 AM Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > Hm I missed that. I feel like time-sliced-of-a-whole gpu is the easier gpu > > cgroups controler to get started, since it's much closer to other cgroups > > that control bandwidth of some kind. Whether it's i/o bandwidth or compute > > bandwidht is kinda a wash. > sriov/time-sliced-of-a-whole gpu does not really need a cgroup > interface since each slice appears as a stand alone device. This is > already in production (not using cgroup) with users. The cgroup > proposal has always been parallel to that in many sense: 1) spatial > partitioning as an independent but equally valid use case as time > sharing, 2) sub-device resource control as opposed to full device > control motivated by the workload characterization paper. It was > never about time vs space in terms of use cases but having new API for > users to be able to do spatial subdevice partitioning. > > > CU mask feels a lot more like an isolation/guaranteed forward progress > > kind of thing, and I suspect that's always going to be a lot more gpu hw > > specific than anything we can reasonably put into a general cgroups > > controller. > The first half is correct but I disagree with the conclusion. The > analogy I would use is multi-core CPU. The capability of individual > CPU cores, core count and core arrangement may be hw specific but > there are general interfaces to support selection of these cores. CU > mask may be hw specific but spatial partitioning as an idea is not. > Most gpu vendors have the concept of sub-device compute units (EU, SE, > etc.); OpenCL has the concept of subdevice in the language. I don't > see any obstacle for vendors to implement spatial partitioning just > like many CPU vendors support the idea of multi-core. > > > Also for the time slice cgroups thing, can you pls give me pointers to > > these old patches that had it, and how it's done? I very obviously missed > > that part. > I think you misunderstood what I wrote earlier. The original proposal > was about spatial partitioning of subdevice resources not time sharing > using cgroup (since time sharing is already supported elsewhere.) Well SRIOV time-sharing is for virtualization. cgroups is for containerization, which is just virtualization but with less overhead and more security bugs. More or less. So either I get things still wrong, or we'll get time-sharing for virtualization, and partitioning of CU for containerization. That doesn't make that much sense to me. Since time-sharing is the first thing that's done for virtualization I think it's probably also the most reasonable to start with for containers. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
