...
/sys/module/kvm/parameters/halt_poll_ns = 0
/sys/kernel/ktimer_lockless_check = 1
/sys/kernel/mm/ksm/run = 2Kernel parameters :
isolcpus=managed_irq,domain,{isolated_cores}
intel_pstate=disable
nosoftlockup
tsc=reliable
nohz=on
nohz_full={isolated_cores}
rcu_nocbs={isolated_cores}
irqaffinity={non_isolated_cores}
processor.max_cstate=1
intel_idle.max_cstate=1
cpufreq.default_governor=performance
rcu_nocb_pollkernel thread priorities :
group.ksoftirqd=0:f:2:*:^\[ksoftirqd
group.ktimers=0:f:2:*:^\[ktimers
group.rcuc=0:f:4:*:^\[rcuc
group.rcub=0:f:4:*:^\[rcub
group.ktimersoftd=0:f:3:*:^\[ktimersoftdconfigures irqbalance with isolated_cores list
configures workqueue with isolated_cores list
kernel.hung_task_timeout_secs = 600
kernel.nmi_watchdog = 0
kernel.sched_rt_runtime_us = -1
vm.stat_interval = 10
kernel.timer_migration = 0
Interrupt Requests
irqbalance
is a daemon for SMP (Symmetric shared-memory multiprocessing) systems to help balance the CPU load generated by interrupts across all of a systems CPUs. irqbalance
identifies the highest volume interrupt sources, and isolates each of them to a single unique CPU, so that load is spread as much as possible over an entire processor set, while minimizing cache miss rates for irq handlers.
The irqmask
define the environment variable IRQBALANCE_BANNED_CPUS
. It sould ignore some CPU and never assign interrupts (more details here, the irqbalance manual). This variable is a mask where the first CPU is the least signifiant bit and specified CPUs in cpusystem
should be set to 0. The workqueuemask
is his negation and it's used to configure the kernel.
Example:
...
Kernel configuration
The cluster is installed with a real-time kernel on each node. So, the kernel run with some parameters:
isolcpus
parameter: Isolate some CPUs from the scheduler. It's the value ofcpumachinesrt
.rcu_nocbs
parameter: Remove one or more CPUsfrom candidates for running callbacks. It's the value ofcpumachinesrt
.
VM configuration
The official documentation on the XML format of libvirt is here.
...