Package: libbitmask1 (2.0-5 and others)

supports multi-word bitmask operations

This Bitmask library supports multi-word bitmask operations for applications programmed in 'C'. It works in conjunction with recent Linux kernel support for processor and memory placement on multiprocessor SMP and NUMA systems. The cpuset library, being developed in parallel, depends on this bitmask library.

Bitmasks provide multi-word bit masks and operations thereon to do such things as set and clear bits, intersect and union masks, query bits, and display and parse masks.

The initial intended use for these bitmasks is to represent sets of CPUs and Memory Nodes, when configuring large SMP and NUMA systems. However there is little in the semantics of bitmasks that is specific to this particular use, and bitmasks should be usable for other purposes that had similar design requirements.

These bitmasks share the same underlying layout as the bitmasks used by the Linux kernel to represent sets of CPUs and Memory Nodes. Unlike the kernel bitmasks, these bitmasks use dynamically allocated memory and are manipulated via a pointer. This enables a program to work correctly on systems with various numbers of CPUs and Nodes, without recompilation.

There is a related cpuset library which uses the bitmask type provided here to represent sets of CPUs and Memory Nodes. The internal representation (as an array of unsigned longs, in little endian order) is directly compatible with the sched_setaffinity(2) and sched_getaffinity(2) system calls (added in Linux 2.6).

Tags: Role: Shared Library

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