Quoting Matt Roper (2018-03-06 23:46:59) > There are cases where a system integrator may wish to raise/lower the > priority of GPU workloads being submitted by specific OS process(es), > independently of how the software self-classifies its own priority. > Exposing "priority offset" as an i915-specific cgroup parameter will > enable such system-level configuration. > > Normally GPU contexts start with a priority value of 0 > (I915_CONTEXT_DEFAULT_PRIORITY) and then may be adjusted up/down from > there via other mechanisms. We'd like to provide a system-level input > to the priority decision that will be taken into consideration, even > when userspace later attempts to set an absolute priority value via > I915_CONTEXT_PARAM_PRIORITY. The priority offset introduced here > provides a base value that will always be added to (or subtracted from) > the software's self-assigned priority value. > > This patch makes priority offset a cgroup-specific value; contexts will > be created with a priority offset based on the cgroup membership of the > process creating the context at the time the context is created. Note > that priority offset is assigned at context creation time; migrating a > process to a different cgroup or changing the offset associated with a > cgroup will only affect new context creation and will not alter the > behavior of existing contexts previously created by the process. > > v2: > - Rebase onto new cgroup_priv API > - Use current instead of drm_file->pid to determine which process to > lookup priority for. (Chris) > - Don't forget to subtract priority offset in context_getparam ioctl to > make it match setparam behavior. (Chris) > > Signed-off-by: Matt Roper <matthew.d.roper@xxxxxxxxx> For ctx->priority/ctx->priority_offset Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> At the end of the day, everything that is modifiable by context is going to want cgroup constraint, but like priority_offset each will require some thought as to how to express the constraint. Interesting conundrum, and still we want a consistent interface for all the gpus on a system. -Chris _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
