Raindrops Aggregate Aggregate::LastDataRecv Aggregate::PMQ InetDiagSocket LastDataRecv Linux ListenStats Middleware Middleware::Proxy Struct TCP_Info Watcher


::new #[] #[]= #capa #decr #evaporate! #incr #initialize_copy #size #size= #to_ary

class Raindrops

Each Raindrops object is a container that holds several counters. It is internally a page-aligned, shared memory area that allows atomic increments, decrements, assignments and reads without any locking.

rd = 4
rd.incr(0, 1)   -> 1
rd.to_ary       -> [ 1, 0, 0, 0 ]

Unlike many classes in this package, the core Raindrops class is intended to be portable to all reasonably modern *nix systems supporting mmap(). Please let us know if you have portability issues, patches or pull requests at



The maximum value a raindrop counter can hold


The size of one page of memory for a mmap()-ed Raindrops region. Typically 4096 bytes under Linux.


The size (in bytes) of a slot in a Raindrops object. This is the size of a word on single CPU systems and the size of the L1 cache line size if detectable.

Defaults to 128 bytes if undetectable.


This is a frozen hash storing the numeric values maps platform-independent symbol keys to platform-dependent numeric values. These states are all valid values for the Raindrops::TCP_Info#state field.

The platform-independent names of the keys in this hash are:


This is only supported on platforms where TCP_Info is supported, currently FreeBSD, OpenBSD, and Linux-based systems.

Public Class Methods  -> raindrops object source

Initializes a Raindrops object to hold size counters. size is only a hint and the actual number of counters the object has is dependent on the CPU model, number of cores, and page size of the machine. The actual size of the object will always be equal or greater than the specified size.

Public Instance Methods

rd[index]    -> value source

Returns the value of the slot designated by index

rd[index] = value source

Assigns value to the slot designated by index

rd.capa              -> Integer source

Returns the number of slots allocated (but not necessarily used) by the Raindrops object.

rd.decr(index[, number])     -> result source

Decrements the value referred to by the index by number. number defaults to 1 if unspecified.

rd.evaporate!        -> nil source

Releases mmap()-ed memory allocated for the Raindrops object back to the OS. The Ruby garbage collector will also release memory automatically when it is not needed, but this forces release under high memory pressure.

rd.incr(index[, number])     -> result source

Increments the value referred to by the index by number. number defaults to 1 if unspecified.

rd.dup               -> rd_copy source

Duplicates and snapshots the current state of a Raindrops object.

rd.size              -> Integer source

Returns the number of counters a Raindrops object can hold. Due to page alignment, this is always equal or greater than the number of requested slots passed to ::new

rd.size = new_size source

Increases or decreases the current capacity of our Raindrop. Raises RangeError if new_size is too big or small for the current backing store

rd.to_ary    -> Array source

converts the Raindrops structure to an Array

Pages Classes Methods
mail archives:
source code: git clone git://
	git clone