[#BloombergLP-bsls-PerformanceHint]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bsls.adoc[bsls]::PerformanceHint
:relfileprefix: ../../
:mrdocs:

This `struct` provides a namespace for a suite of functions that give performance hints to the compiler or hardware.

== Synopsis

Declared in `<bsls_performancehint.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
struct PerformanceHint;
----

== Static Member Functions

[cols="1,4"]
|===
| Name| Description
| xref:BloombergLP/bsls/PerformanceHint/lowFrequency.adoc[`lowFrequency`] 
| This is an empty function that is marked with low execution frequency using pragmas. If this function is placed in a block of code inside a branch, the compiler will optimize the assembly code generated and mark the block as unlikely.
| xref:BloombergLP/bsls/PerformanceHint/prefetchForReading.adoc[`prefetchForReading`] 
| Prefetch one cache line worth of data at the specified `address` for reading if the compiler built‐in is available (see to the component level document for limitations). Otherwise this method has no effect.
| xref:BloombergLP/bsls/PerformanceHint/prefetchForWriting.adoc[`prefetchForWriting`] 
| Prefetch one cache line worth of data at the specified `address` for writing if the compiler built‐in is available (see to the component level document for limitations). Otherwise this method has no effect.
| xref:BloombergLP/bsls/PerformanceHint/rarelyCalled.adoc[`rarelyCalled`] 
| This is an empty function that is marked as rarely called using pragmas. If this function is placed in a block of code inside a branch, the compiler will optimize the assembly code generated and mark the block as unlikely. Note that this function is intentionally not inlined.
|===



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