Manpages - hwlocality_cpubinding.3

enum hwloc_cpubind_flags_t { HWLOC_CPUBIND_PROCESS, HWLOC_CPUBIND_THREAD, HWLOC_CPUBIND_STRICT, HWLOC_CPUBIND_NOMEMBIND }

int hwloc_set_cpubind (hwloc_topology_t topology, hwloc_const_cpuset_t set, int flags)

int hwloc_get_cpubind (hwloc_topology_t topology, hwloc_cpuset_t set, int flags)

int hwloc_set_proc_cpubind (hwloc_topology_t topology, hwloc_pid_t pid, hwloc_const_cpuset_t set, int flags)

int hwloc_get_proc_cpubind (hwloc_topology_t topology, hwloc_pid_t pid, hwloc_cpuset_t set, int flags)

int hwloc_set_thread_cpubind (hwloc_topology_t topology, hwloc_thread_t thread, hwloc_const_cpuset_t set, int flags)

int hwloc_get_thread_cpubind (hwloc_topology_t topology, hwloc_thread_t thread, hwloc_cpuset_t set, int flags)

int hwloc_get_last_cpu_location (hwloc_topology_t topology, hwloc_cpuset_t set, int flags)

int hwloc_get_proc_last_cpu_location (hwloc_topology_t topology, hwloc_pid_t pid, hwloc_cpuset_t set, int flags)

Process/Thread binding flags. These bit flags can be used to refine the binding policy.

The default (0) is to bind the current process, assumed to be single-threaded, in a non-strict way. This is the most portable way to bind as all operating systems usually provide it.

Note

Not all systems support all kinds of binding. See the ’Detailed Description’ section of CPU binding for a description of errors that can occur.

Enumerator

/HWLOC_CPUBIND_PROCESS /

Bind all threads of the current (possibly) multithreaded process.

/HWLOC_CPUBIND_THREAD /

Bind current thread of current process.

/HWLOC_CPUBIND_STRICT /

Request for strict binding from the OS. By default, when the designated CPUs are all busy while other CPUs are idle, operating systems may execute the thread/process on those other CPUs instead of the designated CPUs, to let them progress anyway. Strict binding means that the thread/process will never execute on other cpus than the designated CPUs, even when those are busy with other tasks and other CPUs are idle.

Note

Depending on the operating system, strict binding may not be possible (e.g., the OS does not implement it) or not allowed (e.g., for an administrative reasons), and the function will fail in that case.

When retrieving the binding of a process, this flag checks whether all its threads actually have the same binding. If the flag is not given, the binding of each thread will be accumulated.

Note

This flag is meaningless when retrieving the binding of a thread.

/HWLOC_CPUBIND_NOMEMBIND /

Avoid any effect on memory binding. On some operating systems, some CPU binding function would also bind the memory on the corresponding NUMA node. It is often not a problem for the application, but if it is, setting this flag will make hwloc avoid using OS functions that would also bind memory. This will however reduce the support of CPU bindings, i.e. potentially return -1 with errno set to ENOSYS in some cases.

This flag is only meaningful when used with functions that set the CPU binding. It is ignored when used with functions that get CPU binding information.

hwloc_cpuset_t set, int flags)/ Get current process or thread binding. Writes into =set=/ the physical cpuset which the process or thread (according to flags) was last bound to. /

hwloc_cpuset_t set, int flags)/ Get the last physical CPU where the current process or thread ran. The operating system may move some tasks from one processor to another at any time according to their binding, so this function may return something that is already outdated.

=flags=/ can include either HWLOC_CPUBIND_PROCESS or HWLOC_CPUBIND_THREAD to specify whether the query should be for the whole process (union of all CPUs on which all threads are running), or only the current thread. If the process is single-threaded, flags can be set to zero to let hwloc use whichever method is available on the underlying OS. /

pid, hwloc_cpuset_t set, int flags)/ Get the current physical binding of process =pid=/. /

Note

=hwloc_pid_t=/ is pid_t on Unix platforms, and HANDLE on native Windows platforms./

As a special case on Linux, if a tid (thread ID) is supplied instead of a pid (process ID) and HWLOC_CPUBIND_THREAD is passed in flags, the binding for that specific thread is returned.

On non-Linux systems, HWLOC_CPUBIND_THREAD can not be used in =flags=/. /

hwloc_pid_t pid, hwloc_cpuset_t set, int flags)/ Get the last physical CPU where a process ran. The operating system may move some tasks from one processor to another at any time according to their binding, so this function may return something that is already outdated.

Note

=hwloc_pid_t=/ is pid_t on Unix platforms, and HANDLE on native Windows platforms./

As a special case on Linux, if a tid (thread ID) is supplied instead of a pid (process ID) and *HWLOC_CPUBIND_THREAD*/ is passed in flags, the last CPU location of that specific thread is returned./

On non-Linux systems, *HWLOC_CPUBIND_THREAD*/ can not be used in flags. /

hwloc_thread_t thread, hwloc_cpuset_t set, int flags)/ Get the current physical binding of thread =tid=/. /

Note

=hwloc_thread_t=/ is pthread_t on Unix platforms, and HANDLE on native Windows platforms./

*HWLOC_CPUBIND_PROCESS*/ can not be used in flags. /

hwloc_const_cpuset_t set, int flags)/ Bind current process or thread on cpus given in physical bitmap =set=/. /

Returns

-1 with errno set to ENOSYS if the action is not supported

-1 with errno set to EXDEV if the binding cannot be enforced

pid, hwloc_const_cpuset_t set, int flags)/ Bind a process =pid=/ on cpus given in physical bitmap set. /

Note

=hwloc_pid_t=/ is pid_t on Unix platforms, and HANDLE on native Windows platforms./

As a special case on Linux, if a tid (thread ID) is supplied instead of a pid (process ID) and *HWLOC_CPUBIND_THREAD*/ is passed in flags, the binding is applied to that specific thread./

On non-Linux systems, *HWLOC_CPUBIND_THREAD*/ can not be used in flags. /

hwloc_thread_t thread, hwloc_const_cpuset_t set, int flags)/ Bind a thread =thread=/ on cpus given in physical bitmap set. /

Note

=hwloc_thread_t=/ is pthread_t on Unix platforms, and HANDLE on native Windows platforms./

*HWLOC_CPUBIND_PROCESS*/ can not be used in flags. /