Bottleneck
Encyclopedia
A bottleneck is a phenomenon where the performance or capacity of an entire system is limited by a single or limited number of components or resources. The term bottleneck is taken from the 'assets are water' metaphor. As water is poured out of a bottle, the rate of outflow is limited by the width of the conduit of exit—that is, bottleneck. By increasing the width of the bottleneck one can increase the rate at which the water flows out of the neck at different frequencies. Such limiting components of a system are sometimes referred to as bottleneck points.
is one process in a chain of processes, such that its limited capacity reduces the capacity of the whole chain.
Related concepts in project management are:
And an example is the lack of smelter and refinery
supply which cause bottlenecks upstream.
Another example is in a Surface Mount Technology (SMT) Board Assembly Line with several equipments aligned, usually the common sense is driven to set up and shift the bottleneck element towards the end of the process, inducing the better and faster machines to always keep the PCB supply flowing up, never allowing the slower ones to fully stop, a fact that would be heeded as a deleterious and significant overall drawback on the process.
Four bottlenecks that may occur:
, a bottleneck is a phenomenon by which the performance or capacity of an entire system is severely limited by a single component. Formally, a bottleneck lies on a system's critical path
and provides the lowest throughput. As such, system designers will try to avoid bottlenecks and direct effort towards locating and tuning existing bottlenecks. Some examples of possible engineering bottlenecks are: processor, a communication link, a data processing software, etc.
ically a bottleneck is a section of a route with a carrying capacity substantially below that characterizing other sections of the same route. This is often a narrow part of a road
, perhaps also with a smaller number of lanes, or a reduction of the number of tracks of a railway line. It may be due to a narrow bridge
or tunnel
, a deep cutting or narrow embankment, or work in progress on part of the road or railway.
Capacity bottlenecks are the most vulnerable points in a network and are very often the subject of offensive or defensive military actions. Capacity bottlenecks of strategic importance - such as the Panama Canal
where traffic is limited by the infrastructure - are normally referred to as chokepoints; capacity bottlenecks of tactical value are referred to as mobility corridor
s.
, tracking down bottlenecks (sometimes known as "hot spots" - sections of the code that execute most frequently - i.e. have the highest execution count) is called performance analysis
. Reduction is usually achieved with the help of specialized tools, known as performance analyzers
or profilers. The objective being to make those particular sections of code perform as fast as possible to improve overall algorithmic efficiency
.
of the network is desired, usually opposed to the basic first-come first-served policy. With max-min fairness, data flow between any two nodes is maximized, but only at the cost of more or equally expensive data flows. To put it another way, in case of network congestion any data flow is only impacted by smaller or equal flows.
In such context, a bottleneck link for a given data flow is a link that is fully utilized (is saturated) and of all the flows sharing this link, the given data flow achieves maximum data rate network-wide. Note that this definition is substantially different from a common meaning of a bottleneck. Also note, that this definition does not forbid a single link to be a bottleneck for multiple flows.
A data rate allocation is max-min fair if and only if a data flow between any two nodes has at least one bottleneck link.
In population genetics
, a population bottleneck occurs when the effective population size, Ne
, sharply decreases to a small percentage of the original. The immediate effect of a population bottleneck is to decrease genetic diversity, promoting the effects of stochastic genetic drift
over natural selection
. In the long-term, repeated population bottlenecks can severely decrease population fitness: deleterious alleles are able to accumulate especially where the time interval between bottlenecks does not allow for the generation of new alleles through mutation.
Project management
A bottleneck in project managementProject management
Project management is the discipline of planning, organizing, securing, and managing resources to achieve specific goals. A project is a temporary endeavor with a defined beginning and end , undertaken to meet unique goals and objectives, typically to bring about beneficial change or added value...
is one process in a chain of processes, such that its limited capacity reduces the capacity of the whole chain.
Related concepts in project management are:
- Critical path methodCritical path methodThe critical path method is an algorithm for scheduling a set of project activities. It is an important tool for effective project management.-History:...
- Theory of ConstraintsTheory of ConstraintsThe theory of constraints adopts the common idiom "A chain is no stronger than its weakest link" as a new management paradigm. This means that processes, organizations, etc., are vulnerable because the weakest person or part can always damage or break them or at least adversely affect the...
And an example is the lack of smelter and refinery
Refinery
A refinery is a production facility composed of a group of chemical engineering unit processes and unit operations refining certain materials or converting raw material into products of value.-Types of refineries:Different types of refineries are as follows:...
supply which cause bottlenecks upstream.
Another example is in a Surface Mount Technology (SMT) Board Assembly Line with several equipments aligned, usually the common sense is driven to set up and shift the bottleneck element towards the end of the process, inducing the better and faster machines to always keep the PCB supply flowing up, never allowing the slower ones to fully stop, a fact that would be heeded as a deleterious and significant overall drawback on the process.
Management
Bottleneck occurs in decision making process.Four bottlenecks that may occur:
- Global versus Local
- Center versus Business Unit
- Function versus Function
- Inside versus Outside Partners
Engineering
In engineeringEngineering
Engineering is the discipline, art, skill and profession of acquiring and applying scientific, mathematical, economic, social, and practical knowledge, in order to design and build structures, machines, devices, systems, materials and processes that safely realize improvements to the lives of...
, a bottleneck is a phenomenon by which the performance or capacity of an entire system is severely limited by a single component. Formally, a bottleneck lies on a system's critical path
Critical Path
Critical Path may refer to:*The Critical Path, the longest necessary path through a network of activities when respecting their interdependencies, which may be identified with the Program Evaluation and Review Technique and the Critical path method...
and provides the lowest throughput. As such, system designers will try to avoid bottlenecks and direct effort towards locating and tuning existing bottlenecks. Some examples of possible engineering bottlenecks are: processor, a communication link, a data processing software, etc.
Traffic
MetaphorMetaphor
A metaphor is a literary figure of speech that uses an image, story or tangible thing to represent a less tangible thing or some intangible quality or idea; e.g., "Her eyes were glistening jewels." Metaphor may also be used for any rhetorical figures of speech that achieve their effects via...
ically a bottleneck is a section of a route with a carrying capacity substantially below that characterizing other sections of the same route. This is often a narrow part of a road
Road
A road is a thoroughfare, route, or way on land between two places, which typically has been paved or otherwise improved to allow travel by some conveyance, including a horse, cart, or motor vehicle. Roads consist of one, or sometimes two, roadways each with one or more lanes and also any...
, perhaps also with a smaller number of lanes, or a reduction of the number of tracks of a railway line. It may be due to a narrow bridge
Bridge
A bridge is a structure built to span physical obstacles such as a body of water, valley, or road, for the purpose of providing passage over the obstacle...
or tunnel
Tunnel
A tunnel is an underground passageway, completely enclosed except for openings for egress, commonly at each end.A tunnel may be for foot or vehicular road traffic, for rail traffic, or for a canal. Some tunnels are aqueducts to supply water for consumption or for hydroelectric stations or are sewers...
, a deep cutting or narrow embankment, or work in progress on part of the road or railway.
Capacity bottlenecks are the most vulnerable points in a network and are very often the subject of offensive or defensive military actions. Capacity bottlenecks of strategic importance - such as the Panama Canal
Panama Canal
The Panama Canal is a ship canal in Panama that joins the Atlantic Ocean and the Pacific Ocean and is a key conduit for international maritime trade. Built from 1904 to 1914, the canal has seen annual traffic rise from about 1,000 ships early on to 14,702 vessels measuring a total of 309.6...
where traffic is limited by the infrastructure - are normally referred to as chokepoints; capacity bottlenecks of tactical value are referred to as mobility corridor
Mobility corridor
A mobility corridor is an area where a military force will be canalized due to terrain restrictions. It allows forces to capitalize on the principles of mass and speed, and needs to be relatively free of obstacles....
s.
Bottlenecks in software
In computer programmingComputer programming
Computer programming is the process of designing, writing, testing, debugging, and maintaining the source code of computer programs. This source code is written in one or more programming languages. The purpose of programming is to create a program that performs specific operations or exhibits a...
, tracking down bottlenecks (sometimes known as "hot spots" - sections of the code that execute most frequently - i.e. have the highest execution count) is called performance analysis
Performance analysis
In software engineering, profiling is a form of dynamic program analysis that measures, for example, the usage of memory, the usage of particular instructions, or frequency and duration of function calls...
. Reduction is usually achieved with the help of specialized tools, known as performance analyzers
Performance analysis
In software engineering, profiling is a form of dynamic program analysis that measures, for example, the usage of memory, the usage of particular instructions, or frequency and duration of function calls...
or profilers. The objective being to make those particular sections of code perform as fast as possible to improve overall algorithmic efficiency
Algorithmic efficiency
In computer science, efficiency is used to describe properties of an algorithm relating to how much of various types of resources it consumes. Algorithmic efficiency can be thought of as analogous to engineering productivity for a repeating or continuous process, where the goal is to reduce...
.
Bottlenecks in max-min fairness
In a communication network, sometimes a max-min fairnessMax-min fairness
In communication networks and multiplexing, a division of the bandwidth resources is said to be max-min fair when: firstly, the minimum data rate that a dataflow achieves is maximized; secondly, the second lowest data rate that a dataflow achieves is maximized, etc.In best-effort statistical...
of the network is desired, usually opposed to the basic first-come first-served policy. With max-min fairness, data flow between any two nodes is maximized, but only at the cost of more or equally expensive data flows. To put it another way, in case of network congestion any data flow is only impacted by smaller or equal flows.
In such context, a bottleneck link for a given data flow is a link that is fully utilized (is saturated) and of all the flows sharing this link, the given data flow achieves maximum data rate network-wide. Note that this definition is substantially different from a common meaning of a bottleneck. Also note, that this definition does not forbid a single link to be a bottleneck for multiple flows.
A data rate allocation is max-min fair if and only if a data flow between any two nodes has at least one bottleneck link.
Population genetics
Population genetics
Population genetics is the study of allele frequency distribution and change under the influence of the four main evolutionary processes: natural selection, genetic drift, mutation and gene flow. It also takes into account the factors of recombination, population subdivision and population...
, a population bottleneck occurs when the effective population size, Ne
Effective population size
In population genetics, the concept of effective population size Ne was introduced by the American geneticist Sewall Wright, who wrote two landmark papers on it...
, sharply decreases to a small percentage of the original. The immediate effect of a population bottleneck is to decrease genetic diversity, promoting the effects of stochastic genetic drift
Genetic drift
Genetic drift or allelic drift is the change in the frequency of a gene variant in a population due to random sampling.The alleles in the offspring are a sample of those in the parents, and chance has a role in determining whether a given individual survives and reproduces...
over natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
. In the long-term, repeated population bottlenecks can severely decrease population fitness: deleterious alleles are able to accumulate especially where the time interval between bottlenecks does not allow for the generation of new alleles through mutation.
See also
- Liebig's law of the minimumLiebig's law of the minimumLiebig's Law of the Minimum, often simply called Liebig's Law or the Law of the Minimum, is a principle developed in agricultural science by Carl Sprengel and later popularized by Justus von Liebig...
- Choke pointChoke pointIn military strategy, a choke point is a geographical feature on land such as a valley, defile or a bridge, or at sea such as a strait which an armed force is forced to pass, sometimes on a substantially narrower front, and therefore greatly decreasing its combat power, in order to reach its...
- Performance engineeringPerformance EngineeringPerformance engineering within systems engineering, encompasses the set of roles, skills, activities, practices, tools, and deliverables applied at every phase of the Systems Development Life Cycle which ensures that a solution will be designed, implemented, and operationally supported to meet the...
- Performance analysisPerformance analysisIn software engineering, profiling is a form of dynamic program analysis that measures, for example, the usage of memory, the usage of particular instructions, or frequency and duration of function calls...
- Theory of ConstraintsTheory of ConstraintsThe theory of constraints adopts the common idiom "A chain is no stronger than its weakest link" as a new management paradigm. This means that processes, organizations, etc., are vulnerable because the weakest person or part can always damage or break them or at least adversely affect the...
- Optimization (computer science)Optimization (computer science)In computer science, program optimization or software optimization is the process of modifying a software system to make some aspect of it work more efficiently or use fewer resources...
- Fairness measureFairness measureFairness measures or metrics are used in network engineering to determine whether users or applications are receiving a fair share of system resources. There are several mathematical and conceptual definitions of fairness.-TCP fairness:...
- Max-min fairnessMax-min fairnessIn communication networks and multiplexing, a division of the bandwidth resources is said to be max-min fair when: firstly, the minimum data rate that a dataflow achieves is maximized; secondly, the second lowest data rate that a dataflow achieves is maximized, etc.In best-effort statistical...
- Max-min fairness
- Population bottleneckPopulation bottleneckA population bottleneck is an evolutionary event in which a significant percentage of a population or species is killed or otherwise prevented from reproducing....
- Reverse salientReverse salientThe reverse salient refers to a backward bulge in the advancing line of a military front. The term has been commonly used to analyze military campaigns in the First World War, such as in the Battle of Verdun, where opposing military forces created uneven sections in respective battle lines...