The following kernel command line parameters were used when certifying the SGI UV 300:

"virtefi nobau add_efi_memmap processor.max_cstate=1 nortsched nmi_watchdog=0 log_buf_len=8M pci=hpiosize=0,hpmemsize=0,nobar earlyprintk=ttyS0,115200n8 relax_domain_level=2 cgroup_disable=memory nohz=off pcie_aspm=on highres=of"

These parameters will typically be configured automatically by the SGI Foundation Software bundle provided by SGI. Specific details are as follows:

• virtefi: The default was switched to physical mode. "virtefi" forces it back to virtual mode.

• nobau: Disable the UV BAU from an OS perspective.

• add_efi_memmap: This picks up the extra memmap entries over the standard limit of 128. Required for large SSI configs.

• processor.max_cstate=1: Optimal cstate setting for large configs.

• nortsched: Disable sched_rt_runtime.

• nmi_watchdog=0: Use NMI as a way to get backtraces of processes if the system appears hung.

• log_buf_len=8M: Increase the size from the default 128k.

• pci=hpiosize=0: Required to support PCI hotplug on systems.

• hpmemsize=0: Required to support PCI hotplug on systems with multiple Magma chassis.

• nobar: Disable assigning a resource to a device BAR if that BAR was not assigned by the BIOS.

• earlyprintk=ttyS0,115200n8: This allows early kernel boot messages to display on the serial console.

• relax_domain_level=2: Perform load balancing across other cores in the same package.

• cgroup_disable=memory: Disable memory resource controller.

• nohz=off: Avoids excessive load balancing on a single, otherwise idle hyperthread.

• pcie_aspm=on: Setting Active-State Power Management on.

• highres=off: Turn off high resolution timers.

• pci=hpiosize=0 Required to support PCI hotplug on systems.