bsched Struct Reference

#include <bsched.h>

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Detailed Description

Bandwidth scheduler.

A bandwidth scheduler (`B-sched' for short) is made of:

• A set of I/O sources.
• A set of I/O callbacks to trigger when I/O sources are ready.
• A bandwidth limit per scheduling perdiod.
• A scheduling period.

It operates in cooperation with the I/O sources:

1. Each I/O source registers its I/O callback through the B-sched, so that it is possible to temporarily disable them should we run out of bandwidth for the period.
2. Each I/O source requests an amount of bandwidth to use.
3. After use, each I/O source tells the B-sched how much of the allocated bandwidth it really used.

Periodically, the scheduler runs to compute the amount available for the next period.

A list of stealing schedulers can be added to each scheduler. At the end of the period, any amount of bandwidth that has been unused will be given as "stolem" bandwidth to some of the schedulers stealing from us. Priority is given to schedulers that used up all their bandwidth.

Data Fields
tm_t	last_period
	Last time we ran our period.
GList *	sources
	List of bio_source_t.
GSList *	stealers
	List of bsched_t stealing bw.
gchar *	name
	Name, for tracing purposes.
gint	count
	Amount of sources.
gint	type
	Scheduling type.
gint	flags
	Processing flags.
gint	period
	Fixed scheduling period, in ms.
gint	min_period
	Minimal period without correction.
gint	max_period
	Maximal period without correction.
gint	period_ema
	EMA of period, in ms.
gint	bw_per_second
	Configure bandwidth in bytes/sec.
gint	bw_max
	Max bandwidth per period.
gint	bw_actual
	Bandwidth used so far in period.
gint	bw_last_period
	Bandwidth used last period.
gint	bw_last_capped
	Bandwidth capped last period.
gint	bw_slot
	Basic per-source bandwidth lot.
gint	bw_ema
	EMA of bandwidth really used.
gint	bw_stolen
	Amount we stole this period.
gint	bw_stolen_ema
	EMA of stolen bandwidth.
gint	bw_delta
	Running diff of actual vs.
gint	bw_unwritten
	Data that we could not write.
gint	bw_capped
	Bandwidth we refused to sources.
gint	last_used
	Nb of active sources last period.
gint	current_used
	Nb of active sources this period.
gboolean	looped
	True when looped once over sources.

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Field Documentation

gint bsched::bw_actual

Bandwidth used so far in period.

gint bsched::bw_capped

Bandwidth we refused to sources.

gint bsched::bw_delta

Running diff of actual vs. theoric

gint bsched::bw_ema

EMA of bandwidth really used.

gint bsched::bw_last_capped

Bandwidth capped last period.

gint bsched::bw_last_period

Bandwidth used last period.

gint bsched::bw_max

Max bandwidth per period.

gint bsched::bw_per_second

Configure bandwidth in bytes/sec.

gint bsched::bw_slot

Basic per-source bandwidth lot.

gint bsched::bw_stolen

Amount we stole this period.

gint bsched::bw_stolen_ema

EMA of stolen bandwidth.

gint bsched::bw_unwritten

Data that we could not write.

gint bsched::count

Amount of sources.

gint bsched::current_used

Nb of active sources this period.

gint bsched::flags

Processing flags.

tm_t bsched::last_period

Last time we ran our period.

gint bsched::last_used

Nb of active sources last period.

gboolean bsched::looped

True when looped once over sources.

gint bsched::max_period

Maximal period without correction.

gint bsched::min_period

Minimal period without correction.

gchar* bsched::name

Name, for tracing purposes.

gint bsched::period

Fixed scheduling period, in ms.

gint bsched::period_ema

EMA of period, in ms.

GList* bsched::sources

List of bio_source_t.

GSList* bsched::stealers

List of bsched_t stealing bw.

gint bsched::type

Scheduling type.

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The documentation for this struct was generated from the following file:

• core/bsched.h

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