Archive for the tag 'affinity'

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Setting CPU affinity with taskset

Setting CPU affinity with taskset

taskset retrieves and sets the CPU affinity of a running process (by process ID). It can also be used to launch a process with a given CPU affinity, which binds the specified process to a specified CPU or set of CPUs. However, taskset will not guarantee local memory allocation.

CPU affinity is represented as a bitmask. The lowest-order bit corresponds to the first logical CPU, and the highest-order bit corresponds to the last logical CPU. These masks are typically given in hexadecimal, so that 0×00000001 represents processor 0, and 0×00000003 represents processors 0 and 1.

To set the CPU affinity of a running process, execute the following command, replacing mask with the mask of the processor or processors you want the process bound to, and pid with the process ID of the process whose affinity you wish to change.

# taskset -p mask pid

To launch a process with a given affinity, run the following command, replacing mask with the mask of the processor or processors you want the process bound to, and program with the program, options, and arguments of the program you want to run.

# taskset mask — program

Instead of specifying the processors as a bitmask, you can also use the -c option to provide a comma-delimited list of separate processors, or a range of processors, like so:

# taskset -c 0,5,7-9 — myprogram

Further information about taskset is available from the man page: man taskset and http://redhat.com/