4.2. sciexp2.exprun.cpu

Source: sciexp2/exprun/cpu.py

Functions

get_cpus	Get a set of all physical CPU indexes in the system.
set_freq	Set frequency scaling.
set_irqs	Make irqbalance ignore the given IRQs, and instead set their SMP affinity.

4.2.1. get_cpus

get_cpus(shell, node=None, package=None, core=None, pu=None, cgroup=None)

Get a set of all physical CPU indexes in the system.

It uses the hwloc-calc program to report available CPUs.

Parameters:

shell

Target shell.

node : int or str, optional

NUMA nodes to check. Defaults to all.

package : int or str, optional

Core packages to check on selected NUMA nodes. Defaults to all.

core : int or str, optional

Cores to check on selected core packages. Defaults to all.

pu : int or str, optional

PUs to check on selected cores. Defaults to all.

cgroup : str, optional

Cgroup path.

Returns:

set of int

Physical CPU indexes (as used by Linux).

Notes

The combination of all the arguments is a flexible way to get all the information in the system. Each of these arguments can have any of the forms described under “Hwloc Indexes” in manpage hwloc(7). A few examples.

Second thread of each core: >>> get_cpus(shell, pu=1)

First thread of each core in first NUMA node: >>> get_cpus(node=0, pu=0)

Hardware threads in first core of the entire system: >>> get_cpus(node=0, package=0, core=0)

4.2.2. set_freq

set_freq(shell, path='cpupower', ld_library_path='', freq='max')

Set frequency scaling.

Parameters:

shell

Target shell.

path : str, optional

Path to cpupower tool. Default is use the cpupower tool in the PATH.

ld_library_path : str, optional

Library path to run cpupower tool. Default is use the system’s library path.

freq : str, optional

Frequency to set in GHz. Default is use maximum frequency.

Notes

In some systems it might be necessary to boot the Linux kernel with command line option “intel_pstate=disable” in order to support user frequency settings.

4.2.3. set_irqs

set_irqs(shell, *irqs, **kwargs)

Make irqbalance ignore the given IRQs, and instead set their SMP affinity.

Parameters:

shell

Target system.

irqs

IRQ descriptors.

ignore_errors : bool, optional

Ignore errors when manually setting an IRQ’s SMP affinity. Implies that irqbalance will manage that IRQ. Default is False.

irqbalance_banned_cpus : list of int, optional

CPUs that irqbalance should not use for balancing.

irqbalance_args : list of str, optional

Additional arguments to irqbalance.

Each descriptor in `irqs` is a three-element tuple:

* Type: either ``irq`` for the first column in /proc/interrupts, or

descr for the interrupt description after the per-CPU counts.

* Regex: a regular expression to apply to the fields above, or `True` to

apply to all values (a shorthand to the regex “.*”), or an int (a shorthand to the regex “^int_value$”).

* SMP affinity: list of cpu numbers to set as the IRQ’s affinity; if `True`

is used instead, let irqbalance manage this IRQ.

All matching descriptors are applied in order for each IRQ. If no descriptor

matches, or the last matching descriptor has `True` as its affinity value,

the IRQ will be managed by irqbalance as before.

Returns:

The new irqbalance process.