Search results
Results from the WOW.Com Content Network
For a pair of types K, V, the type map[K]V is the type mapping type-K keys to type-V values, though Go Programming Language specification does not give any performance guarantees or implementation requirements for map types. Hash tables are built into the language, with special syntax and built-in functions.
Alternatively, one can pack the structure, omitting the padding, which may lead to slower access, but uses three quarters as much memory. Although data structure alignment is a fundamental issue for all modern computers, many computer languages and computer language implementations handle data alignment automatically.
The second statement encodes two memory reads (in either order) which must precede the second update of *sum. This guarantees the order of the two addition operations, but potentially introduces a new problem of address aliasing : any of these pointers could potentially refer to the same memory location.
Real implementations of LL/SC do not always succeed even if there are no concurrent updates to the memory location in question. Any exceptional events between the two operations, such as a context switch , another load-link, or even (on many platforms) another load or store operation, will cause the store-conditional to spuriously fail.
Therefore, compilers will attempt to transform the first form into the second; this type of optimization is known as map fusion and is the functional analog of loop fusion. [2] Map functions can be and often are defined in terms of a fold such as foldr, which means one can do a map-fold fusion: foldr f z . map g is equivalent to foldr (f .
Region-based memory management works best when the number of regions is relatively small and each contains many objects; programs that contain many sparse regions will exhibit internal fragmentation, leading to wasted memory and a time overhead for region management. Again, in the presence of region inference this problem can be more difficult ...
In virtual memory implementations and memory management units, a memory map refers to page tables or hardware registers, which store the mapping between a certain process's virtual memory layout and how that space relates to physical memory addresses. In native debugger programs, a memory map refers to the mapping between loaded executable(or ...
In some cases, the elimination of false sharing can result in order-of-magnitude performance improvements. [2] False sharing is an inherent artifact of automatically synchronized cache protocols and can also exist in environments such as distributed file systems or databases, but current prevalence is limited to RAM caches.