rdtset man page

rtdset — Task CPU affinity and Intel(R) Resource Director Technology control tool


rdtset -t <feature=value;...cpu=cpulist>... -c <cpulist> [-I] (-p <pidlist> | [-k] cmd [<args>...])
rdtset -r <cpulist> -t <feature=value;...cpu=cpulist>... -c <cpulist> [-I] (-p <pidlist> | [-k] cmd [<args>...])
rdtset -r <cpulist> -c <cpulist> (-p <pidlist> | [-k] cmd [<args>...])
rdtset -r <cpulist> -t <feature=value;...cpu=cpulist>... [-I] -p <pidlist>
rdtset -t <feature=value> -I [-c <cpulist>] (-p <pidlist> | [-k] cmd [<args>...])


For more details on Intel(R) Resource Director Technology see
or https://github.com/01org/intel-cmt-cat/wiki

The rdtset tool provides support to set up the CAT (Cache Allocation Technology) and MBA (Memory Bandwidth Allocation) capabilities for a task and set its CPU affinity. Current Intel(R) RDT allocation operations of the utility are based on controlling MSR registers (via libpqos library). Class of service 0 (CLOS0) is assumed as default one. In command mode, rdtset forks and one process executes the command. Another process waits for the task to terminate and restores default allocation state by assigning cpu's back to CLOS0. This behavior is not in place in PID mode.


rdtset options are as follow:

-h, --help

Show help

-v, --verbose

Verbose mode

-I, --iface-os

Set the library to use the kernel implementation. If not set the default implementation is to program the MSR's directly.

-t --rdt feature=value;...cpu=cpulist

Specify Intel(R) RDT configuration, single class configuration per -t, multiple -t options allowed.
Accepted values for features:
2, l2 for level 2 cache
3, l3 for level 3 cache
m, mba for MBA

For example:

-t 'l3=0xf;cpu=1'
CPU 1 uses four L3 cache-ways (mask 0xf)

-t 'l3=0xf;cpu=2' -t 'l3=0xf0;cpu=3,4,5'
CPU 2 uses four L3 cache-ways (mask 0xf), CPUs 3-5 share four L3 cache-ways (mask 0xf0), L3 cache-ways used by CPU 2 and 3-4 are non-overlapping

-t 'l3=0xf;cpu=0-2' -t 'l3=0xf0;cpu=3,4,5'
CPUs 0-2 share four L3 cache-ways (mask 0xf), CPUs 3-5 share four L3 cache-ways (mask 0xf0), L3 cache-ways used by CPUs 0-2 and 3-5 are non-overlapping

-t 'l3=0xf,0xf0;cpu=1'
On CDP enabled system, CPU 1 uses four cache-ways for code (mask 0xf) and four cache-ways for data (mask 0xf0), data and code cache-ways are non-overlapping

-t 'mba=70;cpu=0-2'
CPUs 0-2 can utilize up to 70% of available memory bandwidth

-t 'mba=50;l3=0xf;cpu=1'
CPU 1 uses four L3 (mask 0xf) cache-ways and can utilize up to 50% of available memory bandwidth

Example PID type allocation configuration (requires -I option):

-t 'l3=0xf'
Allocate four L3 (mask 0xf) cache-ways to specified PIDs (-p option) or command

-t 'l3=0xf;cpu=1;l3=0x1'
CPU 1 uses four L3 (mask 0xf) cache-ways
Specified PIDs (-p option) or command uses one L3 (mask 0x1) cache-way

-c <cpulist>, --cpu <cpulist>

Specify CPU affinity configuration, a numerical list of processors. The numbers are separated by commas and may include ranges. For example: 1-3,4,5.

-p <pidlist>, --pid <pidlist>

Operate on existing PIDs

-r <cpulist>, --reset <cpulist>

Reset allocation for CPUs (assign COS#0 to listed CPUs)
For example:

-r 0-5
Reset allocation for CPUs 0-5

-r 0-5 -t 'l3=0xf0;cpu=0-5' -c 0-5 -p $BASHPID
Reconfigure allocation for CPUs 0-5
In order to reconfigure allocation, it is needed to reset current configuration

-k, --sudokeep

Do not drop sudo elevated privileges


CAT and MBA are configured using Model Specific Registers (MSRs) to set up the class of service masks and manage the association of the cores/logical threads to a class of service. The rdtset software executes in user space, and access to the MSRs is obtained through a standard Linux*/FreeBSD* interface. Under Linux, the virtual file system structure /dev/cpu/CPUNUM/msr provides an interface to read and write the MSRs, under FreeBSD it is /dev/cpuctlCPUNUM. The msr/cpuctl file interface is protected and requires root privileges. The msr/cpuctl driver might not be auto-loaded and on some modular kernels the driver may need to be loaded manually:

Under Linux:
sudo modprobe msr

Under FreeBSD:
sudo kldload cpuctl

Interface enforcement:
If you require system wide interface enforcement you can do so by setting the "RDT_IFACE" environment variable.

See Also



rdtset was written by Wojciech Andralojc <wojciechx.andralojc@intel.com>, Tomasz Kantecki <tomasz.kantecki@intel.com>, Michal Aleksinski <michalx.aleksinski@intel.com>, Marcel Cornu <marcel.d.cornu@intel.com>

This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


February 21, 2017