Hardware Locality (hwloc)
1.9
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Enumerations | |
enum | hwloc_cpubind_flags_t { HWLOC_CPUBIND_PROCESS, HWLOC_CPUBIND_THREAD, HWLOC_CPUBIND_STRICT, HWLOC_CPUBIND_NOMEMBIND } |
Functions | |
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) |
It is often useful to call hwloc_bitmap_singlify() first so that a single CPU remains in the set. This way, the process will not even migrate between different CPUs. Some operating systems also only support that kind of binding.
The most portable version that should be preferred over the others, whenever possible, is
as it just binds the current program, assuming it is single-threaded, or
which binds the current thread of the current program (which may be multithreaded).
Running lstopo –top can be a very convenient tool to check how binding actually happened.
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.
int hwloc_get_cpubind | ( | hwloc_topology_t | topology, |
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.
int hwloc_get_last_cpu_location | ( | hwloc_topology_t | topology, |
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.
int hwloc_get_proc_cpubind | ( | hwloc_topology_t | topology, |
hwloc_pid_t | pid, | ||
hwloc_cpuset_t | set, | ||
int | flags | ||
) |
Get the current physical binding of process pid
.
hwloc_pid_t
is pid_t
on Unix platforms, and HANDLE
on native Windows platforms.flags
. int hwloc_get_proc_last_cpu_location | ( | hwloc_topology_t | topology, |
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.
hwloc_pid_t
is pid_t
on Unix platforms, and HANDLE
on native Windows platforms.flags
. int hwloc_get_thread_cpubind | ( | hwloc_topology_t | topology, |
hwloc_thread_t | thread, | ||
hwloc_cpuset_t | set, | ||
int | flags | ||
) |
Get the current physical binding of thread tid
.
hwloc_thread_t
is pthread_t
on Unix platforms, and HANDLE
on native Windows platforms.flags
. int hwloc_set_cpubind | ( | hwloc_topology_t | topology, |
hwloc_const_cpuset_t | set, | ||
int | flags | ||
) |
Bind current process or thread on cpus given in physical bitmap set
.
int hwloc_set_proc_cpubind | ( | hwloc_topology_t | topology, |
hwloc_pid_t | pid, | ||
hwloc_const_cpuset_t | set, | ||
int | flags | ||
) |
Bind a process pid
on cpus given in physical bitmap set
.
hwloc_pid_t
is pid_t
on Unix platforms, and HANDLE
on native Windows platforms.flags
. int hwloc_set_thread_cpubind | ( | hwloc_topology_t | topology, |
hwloc_thread_t | thread, | ||
hwloc_const_cpuset_t | set, | ||
int | flags | ||
) |
Bind a thread thread
on cpus given in physical bitmap set
.
hwloc_thread_t
is pthread_t
on Unix platforms, and HANDLE
on native Windows platforms.flags
.