On Wed, Feb 04, 2026 at 07:18:16AM +0000, Wei Liu wrote: > On Mon, Feb 02, 2026 at 07:26:06PM +0000, Stanislav Kinsburskii wrote: > > Query the hypervisor for integrated scheduler support and use it if > > configured. > > > > Microsoft Hypervisor originally provided two schedulers: root and core. The > > Microsoft Hypervisor provides three schedulers: root, classic > (with or without SMT) and core. The latter two are hypervisor based. > > > root scheduler allows the root partition to schedule guest vCPUs across > > physical cores, supporting both time slicing and CPU affinity (e.g., via > > cgroups). In contrast, the core scheduler delegates vCPU-to-physical-core > > scheduling entirely to the hypervisor. > > > > Direct virtualization introduces a new privileged guest partition type - L1 > > Level-1 Virtualization Host. > > > Virtual Host (L1VH) — which can create child partitions from its own > > resources. These child partitions are effectively siblings, scheduled by > > the hypervisor's core scheduler. This prevents the L1VH parent from setting > > affinity or time slicing for its own processes or guest VPs. While cgroups, > > CFS, and cpuset controllers can still be used, their effectiveness is > > unpredictable, as the core scheduler swaps vCPUs according to its own logic > > (typically round-robin across all allocated physical CPUs). As a result, > > the system may appear to "steal" time from the L1VH and its children. > > > > To address this, Microsoft Hypervisor introduces the integrated scheduler. > > This allows an L1VH partition to schedule its own vCPUs and those of its > > guests across its "physical" cores, effectively emulating root scheduler > > behavior within the L1VH, while retaining core scheduler behavior for the > > rest of the system. > > > > The integrated scheduler is controlled by the root partition and gated by > > the vmm_enable_integrated_scheduler capability bit. If set, the hypervisor > > supports the integrated scheduler. The L1VH partition must then check if it > > is enabled by querying the corresponding extended partition property. If > > this property is true, the L1VH partition must use the root scheduler > > logic; otherwise, it must use the core scheduler. This requirement makes > > reading VMM capabilities in L1VH partition a requirement too. > > > > Signed-off-by: Andreea Pintilie <[email protected]> > > Signed-off-by: Stanislav Kinsburskii <[email protected]> > > --- > [...] > > +++ b/include/hyperv/hvhdk_mini.h > > @@ -87,6 +87,9 @@ enum hv_partition_property_code { > > HV_PARTITION_PROPERTY_PRIVILEGE_FLAGS = 0x00010000, > > HV_PARTITION_PROPERTY_SYNTHETIC_PROC_FEATURES = 0x00010001, > > > > + /* Integrated scheduling properties */ > > + HV_PARTITION_PROPERTY_INTEGRATED_SCHEDULER_ENABLED = 0x00020005, > > The internal name is > "HvPartitionPropertyHierarchicalIntegratedSchedulerEnabled". > > You missed the "Hierarchical" part in the property code name. >
I attempt to apply this patch and fix these issues. Unfortunately it doesn't apply cleanly to hyperv-next. Wei
