[thirdparty/squid.git] / doc / Programming-Guide / DelayPools.dox

/**
\page 10_DelayPools Delay Pools

\section Introduction Introduction
\par
	A DelayPool is a Composite used to manage bandwidth for any request
	assigned to the pool by an access expression. DelayId's are a used
	to manage the bandwith on a given request, whereas a DelayPool 
	manages the bandwidth availability and assigned DelayId's.

\section ExtendingDelayPools Extending Delay Pools
\par
	A CompositePoolNode is the base type for all members of a DelayPool.
	Any child must implement the RefCounting primitives, as well as five
	delay pool functions:
	\li	stats() - provide cachemanager statistics for itself.
	\li	dump() - generate squid.conf syntax for the current configuration of the item.
	\li	update() - allocate more bandwith to all buckets in the item.
	\li	parse() - accept squid.conf syntax for the item, and configure for use appropriately.
	\li	id() - return a DelayId entry for the current item.

\par
	A DelayIdComposite is the base type for all delay Id's. Concrete
	Delay Id's must implement the refcounting primitives, as well as two
	delay id functions:
	\li	bytesWanted() - return the largest amount of bytes that this delay id allows by policy.
	\li	bytesIn() - record the use of bandwidth by the request(s) that this delayId is monitoring.

\par
	Composite creation is currently under design review, so see the
	DelayPool class and follow the parse() code path for details.

\section NeatExtensions Neat things that could be done.
\par
	With the composite structure, some neat things have become possible.
	For instance:

\par	Dynamically defined pool arrangements.
	For instance an aggregate (class 1) combined with the per-class-C-net tracking of a 
	class 3 pool, without the individual host tracking. This differs
	from a class 3 pool with -1/-1 in the host bucket, because no memory
	or cpu would be used on hosts, whereas with a class 3 pool, they are
	allocated and used.

\par	Per request bandwidth limits.
	A delayId that contains it's own bucket could limit each request
	independently to a given policy, with no aggregate restrictions.

 */
Commit	Line	Data
8b651fb3	1	/**
	2	\page 10_DelayPools Delay Pools
	3
	4	\section Introduction Introduction
	5	\par
	6	A DelayPool is a Composite used to manage bandwidth for any request
	7	assigned to the pool by an access expression. DelayId's are a used
	8	to manage the bandwith on a given request, whereas a DelayPool
	9	manages the bandwidth availability and assigned DelayId's.
	10
	11	\section ExtendingDelayPools Extending Delay Pools
	12	\par
	13	A CompositePoolNode is the base type for all members of a DelayPool.
	14	Any child must implement the RefCounting primitives, as well as five
	15	delay pool functions:
	16	\li stats() - provide cachemanager statistics for itself.
	17	\li dump() - generate squid.conf syntax for the current configuration of the item.
	18	\li update() - allocate more bandwith to all buckets in the item.
	19	\li parse() - accept squid.conf syntax for the item, and configure for use appropriately.
	20	\li id() - return a DelayId entry for the current item.
	21
	22	\par
	23	A DelayIdComposite is the base type for all delay Id's. Concrete
	24	Delay Id's must implement the refcounting primitives, as well as two
	25	delay id functions:
	26	\li bytesWanted() - return the largest amount of bytes that this delay id allows by policy.
	27	\li bytesIn() - record the use of bandwidth by the request(s) that this delayId is monitoring.
	28
	29	\par
	30	Composite creation is currently under design review, so see the
	31	DelayPool class and follow the parse() code path for details.
	32
	33	\section NeatExtensions Neat things that could be done.
	34	\par
	35	With the composite structure, some neat things have become possible.
	36	For instance:
	37
	38	\par Dynamically defined pool arrangements.
	39	For instance an aggregate (class 1) combined with the per-class-C-net tracking of a
	40	class 3 pool, without the individual host tracking. This differs
	41	from a class 3 pool with -1/-1 in the host bucket, because no memory
	42	or cpu would be used on hosts, whereas with a class 3 pool, they are
	43	allocated and used.
	44
	45	\par Per request bandwidth limits.
	46	A delayId that contains it's own bucket could limit each request
	47	independently to a given policy, with no aggregate restrictions.
	48
	49	*/