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CN113946455A - Multi-stage feedback queue flow scheduling method based on bottleneck perception - Google Patents

Multi-stage feedback queue flow scheduling method based on bottleneck perception Download PDF

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CN113946455A
CN113946455A CN202111202127.8A CN202111202127A CN113946455A CN 113946455 A CN113946455 A CN 113946455A CN 202111202127 A CN202111202127 A CN 202111202127A CN 113946455 A CN113946455 A CN 113946455A
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flow
coflow
queue
bottleneck
optimization
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李明
曹弯弯
尹晓宇
董小菱
来风刚
张攀
段婷婷
张哲�
都繁杰
李静
高丰
常沁楠
吴尚
周逸
乔宇杰
肖雨
程航
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Nanjing University of Aeronautics and Astronautics
State Grid Corp of China SGCC
State Grid Information and Telecommunication Co Ltd
Information and Telecommunication Branch of State Grid Anhui Electric Power Co Ltd
State Grid E Commerce Co Ltd
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Nanjing University of Aeronautics and Astronautics
State Grid Corp of China SGCC
State Grid Information and Telecommunication Co Ltd
Information and Telecommunication Branch of State Grid Anhui Electric Power Co Ltd
State Grid E Commerce Co Ltd
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    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F9/00Arrangements for program control, e.g. control units
    • G06F9/06Arrangements for program control, e.g. control units using stored programs, i.e. using an internal store of processing equipment to receive or retain programs
    • G06F9/46Multiprogramming arrangements
    • G06F9/54Interprogram communication
    • G06F9/546Message passing systems or structures, e.g. queues
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
    • G06F9/00Arrangements for program control, e.g. control units
    • G06F9/06Arrangements for program control, e.g. control units using stored programs, i.e. using an internal store of processing equipment to receive or retain programs
    • G06F9/46Multiprogramming arrangements
    • G06F9/48Program initiating; Program switching, e.g. by interrupt
    • G06F9/4806Task transfer initiation or dispatching
    • G06F9/4843Task transfer initiation or dispatching by program, e.g. task dispatcher, supervisor, operating system
    • G06F9/4881Scheduling strategies for dispatcher, e.g. round robin, multi-level priority queues
    • GPHYSICS
    • G06COMPUTING; CALCULATING OR COUNTING
    • G06FELECTRIC DIGITAL DATA PROCESSING
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Abstract

The invention discloses a bottleneck perception-based multi-stage feedback queue flow scheduling method, which comprises the following steps: after the main node generates the flow, initially distributing queue priority and monitoring the link state according to the flow information; with the continuous increase of the flow, the flow scheduling problem is modeled, and the flow rate and throughput are increased by modeling through Lagrange dual optimization of the flow scheduling problem; aiming at the problem of network congestion caused by increasing throughput, a multi-stage queue feedback mechanism is designed, and a bottleneck factor is constructed according to the size, width and flow rate information of sent flow; and taking the minimized flow completion time as an optimization target, and dynamically adjusting the priority of the multistage feedback queue according to the size of the bottleneck factor through Lyapunov optimization. The invention can fully use the link bandwidth and reduce CCT; the overall stability of the queue is ensured, the congestion is reduced, the throughput is increased while the average CCT is reduced, and the link utilization rate is improved.

Description

Multi-stage feedback queue flow scheduling method based on bottleneck perception
Technical Field
The invention relates to the technical field of cloud computing communication, in particular to a bottleneck perception-based multi-level feedback queue flow scheduling method.
Background
With the explosive development of cloud data centers, the internal traffic volume thereof is explosively increased, and great challenges are created for the traditional traffic scheduling mechanism. In order to process mass data, a large number of computing nodes are required to work cooperatively, and a data parallel computing framework is widely applied to cloud computing data centers, such as Apache Spark, Dryad, MapReduce, CIEL and the like. In such a framework, a task produces results through a series of computation and communication phases, typically with a rule at the end of each communication phase: the following calculation phase can only be started after all the input data have been received. Since the communication phase may account for more than 50% of the task completion time, the performance of the application will be significantly affected. This fully explains that networks in data centers have become the bottleneck of data parallel frameworks. Management and optimization of network resources in a data center is therefore important to shorten the completion time of tasks. However, conventional stream-level optimization cannot meet the requirements of low latency and high throughput of applications, and is therefore not efficient enough in application optimization. In this case, the advent of the Coflow made up the gap between the application and the framework.
In the existing research, the flow is called a group of communication data flows with semantic correlation, communication information in a parallel application program can be captured, the flow can be used as a basic element of network resource allocation or scheduling, an optimization target can be better achieved, and reducing the flow completion time (CCT) is generally called a flow scheduling problem, and the flow scheduling is widely applied to data center transmission design. In order to effectively reduce the average CCT of the flow, a number of flow scheduling methods, such as Varys, Aalo, Baraat, etc., have emerged, all of which reduce the average CCT to some extent.
However, the existing flow scheduling method has certain defects, a network is abstracted into a non-blocking large-scale switch, network resource limitation is ignored, and most of the method does not consider network bottlenecks. In a cloud data center, due to the influences of link failure, unbalanced routing and the like in a network, congestion may occur on a core link, and the bottleneck of traffic is transferred to the inside of the network. Bottlenecks within the network determine how many bandwidth streams are actually available, directly affecting the CCT. Therefore, in order to obtain the desired CCT performance, bottlenecks in the network must be considered. In general, in the existing research, the CCT performance is poor due to the bottleneck problem in the network, the method starts from the bottleneck perception point of view, analyzes the typical scene of the Coflow scheduling under the cloud data center architecture, and provides a multi-stage feedback queue Coflow scheduling mechanism based on the bottleneck perception.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a bottleneck perception-based multi-level feedback queue flow scheduling method, which comprises the steps of firstly, initially distributing queue priority according to flow information and monitoring a link state, and then, through Lagrange dual optimization modeling, increasing the flow rate of the flow and increasing the throughput; aiming at the problem of network congestion caused by increasing throughput, a multi-stage queue feedback mechanism is designed, and a bottleneck factor is constructed according to the size, width and flow rate information of sent flows; the priority of the multi-stage feedback queue is dynamically adjusted according to the size of the bottleneck factor, link contention is reduced, the link utilization rate is improved, and congestion perception is realized, so that CCT is reduced, and the flow scheduling performance is enhanced.
In order to achieve the purpose, the invention adopts the following technical scheme:
a multi-stage feedback queue flow scheduling method based on bottleneck perception comprises the following steps:
s1, after the main node generates the Coflow flow, the main node initially distributes queue priority and monitors the link state according to the Coflow information;
s2, modeling a Coflow scheduling problem along with the continuous increase of the Coflow flow, and increasing the flow rate and throughput by modeling the Coflow scheduling problem through Lagrange dual optimization; aiming at the problem of network congestion caused by increasing throughput, a multi-stage queue feedback mechanism is designed, and a bottleneck factor is constructed according to the size, width and flow rate information of sent flow; and taking the minimized flow completion time as an optimization target, and dynamically adjusting the priority of the multistage feedback queue according to the size of the bottleneck factor through Lyapunov optimization.
In order to optimize the technical scheme, the specific measures adopted further comprise:
further, in step S1, the initial allocation of the queue priority according to the flow information means:
the bandwidth of each flow is evenly distributed, and the waiting queue adopts a FIFO strategy.
Further, in step S2, the process of modeling the Coflow scheduling problem includes the following steps:
assuming a cloud computing data center, which is provided with N hosts and M exchangers and has an arbitrary topological structure, to form L links; suppose Coflow CiHas all information about its stream and at time TiThe transmission is started immediately when the network is reached, and the time T is more than or equal to TiWhile, flow CiIs assigned to a rate
Figure BDA00033053722400000210
Path B oflThe above step (1); the flow scheduling problem is modeled as follows:
Figure BDA0003305372240000021
in the formula, Sk(t) represents the size of the Coflow transmitted flow within time t, df(t) residual data of flow f in time t, 1/Sk(t)+df(t) flow velocity as flow f
Figure BDA0003305372240000029
Weight of (3), weighted sum minimization;
Figure BDA0003305372240000022
the desired bandwidth rate allocated for flow f in link l;
Figure BDA0003305372240000023
is the completion time of the w-th flow of Coflow K, where K represents the total number of Coflow flows and K represents the K-th Coflow flow; since the kth Coflow flow contains W inside itkThe w-th flow of Coflow k is denoted by w.
Further, modeling by Lagrange dual optimization Coflow scheduling problem, the process of increasing the Coflow flow rate and throughput includes the following steps:
the flow scheduling problem model is converted into:
Figure BDA0003305372240000024
for the (r, lambda, v) triad, r represents the flow velocity of the Coflow flow, D represents the value range of the flow velocity r, and the flow velocity r is solved to obtain
Figure BDA0003305372240000025
So as to minimize the dual function,
Figure BDA0003305372240000026
representing the value of an equation in the flow scheduling problem;
Figure BDA0003305372240000027
constraint of inequality in Lagrange dual optimization;
Figure BDA0003305372240000028
constraint for equality in Lagrange dual optimization; (λ, v) is Lagrange dual parameter, g (λ, v) is dual problem of original Coflow scheduling problem; (lambdai,vj) Are respectively inequality constraints
Figure BDA0003305372240000031
Constraint of equality
Figure BDA0003305372240000032
Dual parameters of (d); l denotes the total number of links, j denotes the jth link, BjRepresenting the bandwidth of the jth link; p is a radical ofklIndicating whether flow k occupies link l, pkl∈{0,1};df(t) represents the remaining amount of data within stream f at time t;
solving for (r, lambda, v) by gradient descent, let
Figure BDA00033053722400000315
And (lambda)*,v*) Respectively is a pair of optimal solutions of the original problem and the dual problem, and the dual gap is zero;
solving the Coflow scheduling problem through Lagrange optimization, converting the original Coflow scheduling problem into a convex problem, and solving the maximum flow rate of the Coflow.
Further, in step S2, the process of dynamically adjusting the priority of the multi-level feedback queue according to the size of the bottleneck factor through Lyapunov optimization with the goal of minimizing the flow completion time as an optimization goal includes the following steps:
the transmit queue model is built as follows:
Figure BDA0003305372240000033
Figure BDA0003305372240000034
Figure BDA0003305372240000035
Figure BDA0003305372240000036
in the formula (I), the compound is shown in the specification,
Figure BDA0003305372240000037
is the maximum flow rate, beta represents the ratio of the sent size to the width of the flow of Coflow,
Figure BDA0003305372240000038
is a strictly convex function of the intensity of the light,
Figure BDA0003305372240000039
is the bottleneck factor of the flow waiting queue within time t; the priority of the flow in the virtual queue is related to beta, the larger the data sent by the flow is, the larger the size of the data is, and the smaller the width of the data is, the higher the priority is;
Figure BDA00033053722400000310
is the bandwidth rate allocated by stream f in link i during time t,
Figure BDA00033053722400000311
represents the maximum flow benefit (throughput is maximum);
the virtual queue is:
Figure BDA00033053722400000312
in the formula, Ql(t) represents the length of the virtual queue over time t, which is related to the flow rate of the distributed flow of Coflow
Figure BDA00033053722400000313
And link bandwidth BlDirect correlation, l (l) denotes the total link set;
solving the stability of the queue by adopting Lyapunov drift, and obtaining the expected flow rate as follows:
Figure BDA00033053722400000314
solving the optimal solution of each link
Figure BDA0003305372240000041
To minimize the flow completion time, where Ul(t) represents the total length of the virtual queue, r, over time tmaxRepresenting the maximum flow rate achieved by Lagrange optimization, where V is a non-negative parameter representing a penalty factor, affects the performance tradeoff between the optimal objective function value and the convergence time required to meet the desired constraints.
The invention has the beneficial effects that:
the invention provides a multi-level feedback queue flow scheduling mechanism (BamHI) based on bottleneck perception; firstly, analyzing the network bottleneck problem in the cloud data center flow scheduling process, and aiming at the bottleneck problem in the network, optimizing the flow velocity by Lagrange dual, fully using link bandwidth and reducing CCT; then, for the bottleneck problem between networks, according to the bottleneck factor, network congestion is sensed, a multi-level feedback queue model is improved, Lyapunov optimization is utilized, the overall stability of a queue is ensured, congestion is reduced, and when the average CCT is reduced, the throughput is increased and the link utilization rate is improved by adopting a BamH scheduling mechanism.
Drawings
Fig. 1 is a diagram of a multi-stage feedback queue flow scheduling structure based on bottleneck sensing according to an embodiment of the present invention.
Fig. 2 is a flowchart of a bottleneck-aware-based multi-stage feedback queue flow scheduling method according to an embodiment of the present invention.
Fig. 3 is a comparison diagram of completion times of a multi-stage feedback queue flow scheduling method based on bottleneck sensing according to an embodiment of the present invention and a conventional method.
Fig. 4 is a graph comparing throughput of a multi-stage feedback queue flow scheduling method based on bottleneck perception and the prior art, provided by the embodiment of the present invention.
Detailed Description
The present invention will now be described in further detail with reference to the accompanying drawings.
It should be noted that the terms "upper", "lower", "left", "right", "front", "back", etc. used in the present invention are for clarity of description only, and are not intended to limit the scope of the present invention, and the relative relationship between the terms and the terms is not limited by the technical contents of the essential changes.
As shown in FIG. 1, the invention discloses a bottleneck-aware-based multi-level feedback queue flow scheduling method, wherein a scheduling model of the method comprises a master node, a work node, a daemon process and a monitor. The master node is the brain of the system, which acts as a controller. And the daemon is used as a global scheduler to cooperatively process the optimization information of the main node and the working node, collects the flow information from the working node and executes the flow priority scheduling. And the monitoring module collects the flow information, monitors the link state and judges the congestion condition. The flow chart of the present invention is shown in fig. 2, and the scheduling process includes the following steps:
s1, information collection
Since the flow is a group of communication data flows with semantic correlation, if a group of flow flows is not transmitted, the number of bytes transmitted by each flow, the flow relationship and the flow width information cannot be obtained in advance. The monitoring module collects the flow related information on one hand and monitors the state of the whole network on the other hand. When the flow is more, link contention is generated, which causes network congestion; and collecting network information by information collection, and then transmitting the information to a scheduler for network optimization.
S2, preprocessing data
When a group of flow flows enter a cloud computing data center, a daemon initializes flow scheduling and adopts a simple scheduling mechanism, namely: the daemon process equally distributes the bandwidth of each flow, the waiting queue adopts FIFO strategy and the like, the network bandwidth is distributed fairly, and each flow can be sent.
S3 performance optimization
With the continuous increase of the flow, the just-coming flow waits for the flow transmission of the first-coming flow, which causes queuing in the virtual queue, and since the initialized flow scheduling adopts a policy of allocating bandwidth on average, a large amount of residual space is caused, which greatly affects the scheduling performance of the flow. Aiming at the problems, the monitoring node monitors the link condition in real time, and when congestion is detected, the scheduler of the main node is immediately informed to further optimize. By using Lagrange optimization, the partial flow velocity is increased, thereby shortening the CCT; however, when the throughput is increased, link competition can be generated, and partial flows can enter a waiting queue to influence the CCT performance; and (3) adopting Lyapunov optimization, allocating different priorities to the flow according to the bottleneck factors in the flow in the waiting queue, and scheduling preferentially to achieve a stable state of increasing throughput and reducing congestion, and finally reducing CCT.
In order to optimize the technical scheme, the specific measures adopted further comprise:
further, step S3 includes:
s31, modeling a flow scheduling process: assuming a cloud computing data center, which is provided with N hosts and M exchangers and has an arbitrary topological structure, to form L links; and then, abstracting an undirected graph G (V, E), where | V | ═ N + M and | E | ═ L, and for the undirected graph G, a node V corresponds to a node of the cloud computing data center, and each edge E represents a full-duplex link. Without loss of generality, Coflow C is assumediHas all information about its stream and at time TiThe transmission is started immediately when the network is reached, and the time T is more than or equal to TiWhile, flow CiIs assigned to a rate
Figure BDA0003305372240000051
Path B oflThe above. The basic notation used in this section is as follows.
Figure BDA0003305372240000052
On this basis, the scheduling problem is represented as an optimization problem in time t:
Figure BDA0003305372240000056
the constraint conditions that should be satisfied are as follows:
Figure BDA0003305372240000057
Figure BDA0003305372240000055
Figure BDA0003305372240000061
Figure BDA0003305372240000062
transforming the formula into:
Figure BDA0003305372240000063
the constraint equation reflects the link state, which means that the aggregate flow bandwidth cannot exceed the link capacity (i.e., the bottleneck in the network) at any time; to simplify the model, the bandwidth allocated for the Coflow per unit time is considered as the sum of the flow rates allocated for the Coflow. On the one hand, to minimize CCT, the problem can be seen as a linear programming problem. 1/Sk(t)+df(t) flow velocity which can be regarded as flow f
Figure BDA00033053722400000610
Then the weighted sum is minimized. To minimize the weighted sum, i.e. the flow rate needs to be increased; on the other hand, increasing the flow rate can cause link contention, create an inter-link bottleneck, cause congestion, and can instead damage the overall CCT. Therefore, there is a need to find a balance between increasing throughput and reducing bottlenecks.
Furthermore, minimizing CCT is an NP-hard problem. In actual production, multiple coflows in the network may compete for link resources at the same time, which makes the Coflow scheduling more complicated. Convex optimization is widely applied to the field of machine learning and the like, and the convex structure in the non-convex optimization problems is found out at present, so that a plurality of non-convex optimization problems are broken through. For the NP-hard problem of minimized CCT, the solution rate can be greatly increased by converting the original problem into a convex problem.
S32 Lagrange optimizing scheduling
For the NP-hard problem of minimized CCT, the solution rate can be greatly increased by converting the original problem into a convex problem. The Lagrange duality idea is to consider the constraint condition of the problem in the objective function, and the method is used for solving through Lagrange duality. The Lagrange dual function of the primitive function is then:
Figure BDA0003305372240000064
for the (r, λ, v) triplet, r represents the flow rate of the flow stream, (λ, v) is the Lagrange dual parameter, and g (λ, v) is the dual problem of the original problem. Since the dual function is a point-by-point infimum of a family of affine functions about (λ, v). In addition, the dual function is the optimal solution p of the original problem*The lower bound of (a), i.e., the following holds for any λ ≧ 0 and v
g(λ,v)≤p*
Solving for (r, lambda, v) by gradient descent, let
Figure BDA0003305372240000065
And (lambda)*,v*) The method is characterized in that the method is respectively a pair of optimal solutions of an original problem and a dual problem, and the dual gap is zero. Because of the fact that
Figure BDA0003305372240000066
Is about
Figure BDA0003305372240000067
Minimum in
Figure BDA0003305372240000068
Takes a minimum value, so the function is
Figure BDA0003305372240000069
The gradient at (a) is zero, i.e.:
Figure BDA0003305372240000071
obviously, must exist (lambda)*,v*) So that the following holds:
Figure BDA0003305372240000072
the Lagrange optimization is used for converting the original problem into a convex optimization problem to be solved, so that the solving speed is increased; by solving an optimal solution for each link
Figure BDA00033053722400000714
Ensuring that the CCT is taken to a minimum. Since the CCT is reduced by increasing the flow rate of the Coflow flow, link contention is objectively caused, and network congestion is formed.
S33, Lyapunov optimization scheduling
Since increasing the flow rate will occupy the link bandwidth as much as possible, the flow rate will be backlogged in the waiting queue, resulting in network congestion. And designing a brand-new bottleneck factor by the BamH, ensuring the stability of the queue and further optimizing the flow scheduling of the multi-stage feedback queue. Global stability, among other things, means ensuring that the network is always pursuing an ideal state to ensure that all arriving data leaves the buffer for a limited time, thereby ensuring throughput, fairness, and load balancing. In reality, the network is rarely in equilibrium, but global stability may enable the congestion control algorithm to ensure that it has the desired equalization characteristics.
The transmit queue model is built as follows:
Figure BDA0003305372240000073
Figure BDA0003305372240000074
Figure BDA0003305372240000075
Figure BDA0003305372240000076
here, the
Figure BDA0003305372240000077
Is the maximum flow rate of the flow,
Figure BDA0003305372240000078
is a strictly convex function of the intensity of the light,
Figure BDA0003305372240000079
is a bottleneck factor. On one hand, the priority of the flow in the virtual queue is related to β, that is, the larger the data sent by the flow is, the larger the size of the data itself is, and the smaller the width of the flow is, the higher the priority is. On the other hand, in the case of a liquid,
Figure BDA00033053722400000710
is the flow rate of the flow, and the flow rate state directly reflects the congestion condition of the link, so the flow rate
Figure BDA00033053722400000711
The impact on the priority of the flow in the virtual queue is very critical.
Virtual queue:
Figure BDA00033053722400000712
Ql(t) represents the length of the virtual queue, which is related to the flow rate of the distributed flow
Figure BDA00033053722400000713
And link bandwidth BlAre directly related.
Due to the randomness of the arrival of computational tasks, queue stability is a key constraint to guarantee strict service delays, discrete time queuingTeam Process Ql(t) achieving queue steady state is defined as follows:
Figure BDA0003305372240000081
the Lyapunov function is defined as follows:
Figure BDA0003305372240000082
the conditional Lyapunov drift per unit time can be expressed as
Δ(Q(t))=E{L(Q(t+1))-L(Q(t))|Q(t)}
The queue stability was solved using the Lyapunov drift Δ (q (t)).
Next, the DPP expression of the virtual queue becomes:
Figure BDA0003305372240000083
where V is a penalty factor, network stability can be derived by minimizing the equation. However, random and non-linear Lyapunov drift is difficult. The minimum value is obtained by deducing the upper bound of the original equation, and then taking the minimized upper bound as a target. Under the heuristic search algorithm based on Lyapunov optimization,
Figure BDA0003305372240000084
and
Figure BDA0003305372240000085
the following inequality holds for DPP:
Figure BDA0003305372240000086
defining α as an upper bound for the worst case value. The value α is limited because of the aggregationχIs assumed to be continuous, with for each time slot
Figure BDA0003305372240000087
Given a time gap t, by searching
Figure BDA0003305372240000088
So that
Figure BDA0003305372240000089
And minimum. Minimization of use
Figure BDA00033053722400000810
To update the queue value Q of the next time slot1(t+1),...,QL(t + 1). Obtaining a special solution:
Figure BDA00033053722400000811
since the flow scheduling is a method that approximates actual network dynamic queuing, this method is a good approximation of network performance, given that all arrivals are placed immediately on all links of a path.
The invention provides a bottleneck perception-based multi-level feedback queue flow scheduling method (BamH), which is characterized in that a real data set of Facebook is used for verifying a flow scheduling mechanism on the basis of a small-scale flow level simulator and an open source network simulator, and the effectiveness of the bottleneck perception-based multi-level feedback queue flow scheduling method is verified by comparing the scheduling mechanism under the scene that the prior knowledge is known and the prior knowledge is unknown. A comparison of the Coflow completion times of the prior art method and BamHI is obtained as shown in FIG. 3. As can be seen from FIG. 3, the average CCT ratio of BamHI to BamHI is 9.2%, 13.5%, 39.1% higher than that of Baraat, Varys, Aalo, respectively. This is because Bamq considers bottlenecks within the network and thus more accurate flow priority and bandwidth allocation than Varys, using a more efficient priority scheduling method than baraat (fifo). Another reason is that Varys link utilization is not high, while Bamq improves link utilization. Fig. 4 compares the throughput of 4 mechanisms at different workloads, which also partially explains the better CCT performance of Bamq in fig. 3. Throughput is the maximum completion time of all data transmitted through the entire network divided by all coflows. At lower loads (4 algorithms have similar throughput, while at higher loads the throughput of Bamq is significantly higher than Varys (21.3% at 100% load), slightly lower than Baraat (4.2% at 100 load), with a convergence process for Bamq relative to Baraat, so that the throughput loss is small.
The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions belonging to the idea of the present invention belong to the protection scope of the present invention. It should be noted that modifications and embellishments within the scope of the invention may be made by those skilled in the art without departing from the principle of the invention.

Claims (5)

1.一种基于瓶颈感知的多级反馈队列Coflow调度方法,其特征在于,所述调度方法包括以下步骤:1. a multi-level feedback queue Coflow scheduling method based on bottleneck perception, is characterized in that, described scheduling method comprises the following steps: S1,主节点产生Coflow流后,根据Coflow信息初始分配队列优先级并监控链路状态;S1, after the master node generates a Coflow flow, it initially assigns queue priorities according to the Coflow information and monitors the link status; S2,随着Coflow流不断增加,对Coflow调度问题建模,通过Lagrange对偶优化Coflow调度问题建模,增加Coflow流速和吞吐量;其中,针对增大吞吐量而产生网络拥塞的问题,设计多级队列反馈机制,根据已发流的大小、宽度和流速信息,构建瓶颈因子;以最小化Coflow完成时间为优化目标,通过Lyapunov优化,根据瓶颈因子大小动态调整多级反馈队列的优先级。S2, with the continuous increase of Coflow flow, the Coflow scheduling problem is modeled, and the Coflow scheduling problem is modeled by Lagrange dual optimization to increase the Coflow flow rate and throughput; among them, for the problem of network congestion caused by increasing throughput, a multi-level design is designed. The queue feedback mechanism constructs the bottleneck factor according to the size, width and flow rate information of the sent flow; with the optimization goal of minimizing the completion time of Coflow, through Lyapunov optimization, the priority of the multi-level feedback queue is dynamically adjusted according to the size of the bottleneck factor. 2.根据权利要求1所述的基于瓶颈感知的多级反馈队列Coflow调度方法,其特征在于,步骤S1中,根据Coflow信息初始分配队列优先级是指:2. the multi-level feedback queue Coflow scheduling method based on bottleneck perception according to claim 1, is characterized in that, in step S1, according to Coflow information initial allocation queue priority refers to: 平均分配每个流的带宽,等待队列采用FIFO的策略。The bandwidth of each stream is evenly distributed, and the waiting queue adopts a FIFO policy. 3.根据权利要求1所述的基于瓶颈感知的多级反馈队列Coflow调度方法,其特征在于,步骤S2中,对Coflow调度问题建模的过程包括以下步骤:3. the multi-level feedback queue Coflow scheduling method based on bottleneck perception according to claim 1, is characterized in that, in step S2, the process of Coflow scheduling problem modeling comprises the following steps: 假设一个云计算数据中心,拥有N个主机、M台交换器,具有任意的拓扑结构,形成L条链路;假设Coflow Ci拥有关于它的流的所有信息,并在时间Ti到达网络时立即开始传输,在时间t≥Ti时,流Ci被分配到速率
Figure FDA0003305372230000011
的路径Bl上;对Coflow调度问题建模如下:
Suppose a cloud computing data center has N hosts, M switches, and an arbitrary topology, forming L links; Suppose Coflow C i has all the information about its flow, and when time T i arrives at the network Transmission starts immediately, and at time t ≥ T i , stream C i is assigned to the rate
Figure FDA0003305372230000011
on the path B l of ; the Coflow scheduling problem is modeled as follows:
Figure FDA0003305372230000012
Figure FDA0003305372230000012
式中,Sk(t)表示时间t内Coflow已发送流的大小,df(t)表示时间t内流f的剩余数据,1/Sk(t)+df(t)看做流f的流速
Figure FDA0003305372230000013
的权重,加权和求最小;
Figure FDA0003305372230000014
为链路l中流f分配的期望带宽速率;
Figure FDA0003305372230000015
是Coflow k的第w个流的完成时间,其中K表示Coflow流的总数,k表示第k个Coflow流;第k个Coflow流其内部包含Wk个子流,采用w表示Coflow k的第w个流。
In the formula, Sk (t) represents the size of the stream sent by Coflow in time t, d f (t) represents the remaining data of stream f in time t, and 1/S k (t)+d f (t) is regarded as the stream flow velocity of f
Figure FDA0003305372230000013
The weight of , and the weighted sum is minimized;
Figure FDA0003305372230000014
Desired bandwidth rate allocated for flow f in link l;
Figure FDA0003305372230000015
is the completion time of the wth flow of Coflow k, where K represents the total number of Coflow flows, and k represents the kth Coflow flow; the kth Coflow flow contains W k subflows, and w represents the wth flow of Coflow k. flow.
4.根据权利要求3所述的基于瓶颈感知的多级反馈队列Coflow调度方法,其特征在于,通过Lagrange对偶优化Coflow调度问题建模,增加Coflow流速和吞吐量的过程包括以下步骤:4. the multi-level feedback queue Coflow scheduling method based on bottleneck perception according to claim 3, is characterized in that, by Lagrange dual optimization Coflow scheduling problem modeling, the process that increases Coflow flow velocity and throughput may further comprise the steps: 将Coflow调度问题模型转变为:Transform the Coflow scheduling problem model into:
Figure FDA0003305372230000016
Figure FDA0003305372230000016
对于(r,λ,v)三元组,r表示Coflow流的流速,D表示流速r的取值范围,通过求解流速r得到
Figure FDA0003305372230000021
以使对偶函数取得最小,
Figure FDA0003305372230000022
表示Coflow调度问题中等式的取值;
Figure FDA0003305372230000023
为Lagrange对偶优化中的不等式约束;
Figure FDA0003305372230000024
为Lagrange对偶优化中的等式约束;(λ,v)则是Lagrange对偶参数,g(λ,v)为原Coflow调度问题的对偶问题;(λi,vj)分别为不等式约束
Figure FDA0003305372230000025
等式约束
Figure FDA0003305372230000026
的对偶参数;L表示链路总数,j表示第j条链路,Bj表示第j条链路的带宽,pkl表示流k是否占用链路l,pkl∈{0,1};df(t)表示时间t内流f的剩余数据量;
For the (r,λ,v) triplet, r represents the flow velocity of the Coflow flow, and D represents the value range of the flow velocity r, which can be obtained by solving the flow velocity r
Figure FDA0003305372230000021
to minimize the dual function,
Figure FDA0003305372230000022
Represents the value of the equation in the Coflow scheduling problem;
Figure FDA0003305372230000023
Inequality constraints in Lagrange dual optimization;
Figure FDA0003305372230000024
is the equality constraint in Lagrange dual optimization; (λ, v) is the Lagrange dual parameter, g(λ, v) is the dual problem of the original Coflow scheduling problem; (λ i , v j ) are inequality constraints, respectively
Figure FDA0003305372230000025
equality constraints
Figure FDA0003305372230000026
The dual parameter of ; L represents the total number of links, j represents the jth link, B j represents the bandwidth of the jth link, p kl represents whether flow k occupies link l, p kl ∈ {0,1}; d f (t) represents the remaining data amount of stream f in time t;
通过梯度下降求解(r,λ,v),令
Figure FDA0003305372230000027
和(λ*,v*)分别是原问题和对偶问题的某对最优解,对偶间隙为零;
Solve (r,λ,v) by gradient descent, let
Figure FDA0003305372230000027
and (λ * , v * ) are a pair of optimal solutions of the original problem and the dual problem, respectively, and the dual gap is zero;
通过Lagrange优化求解Coflow调度问题,将原Coflow调度问题转换为凸问题,求解出Coflow的最大流速。The Coflow scheduling problem is solved by Lagrange optimization, the original Coflow scheduling problem is converted into a convex problem, and the maximum flow rate of Coflow is solved.
5.根据权利要求3所述的基于瓶颈感知的多级反馈队列Coflow调度方法,其特征在于,步骤S2中,以最小化Coflow完成时间为优化目标,通过Lyapunov优化,根据瓶颈因子大小动态调整多级反馈队列的优先级的过程包括以下步骤:5. the multi-level feedback queue Coflow scheduling method based on bottleneck perception according to claim 3, is characterized in that, in step S2, with minimizing Coflow completion time as optimization target, by Lyapunov optimization, according to bottleneck factor size dynamic adjustment multi-level. The process of prioritizing feedback queues includes the following steps: 建立发送队列模型如下:Create a send queue model as follows:
Figure FDA0003305372230000028
Figure FDA0003305372230000028
Figure FDA0003305372230000029
Figure FDA0003305372230000029
Figure FDA00033053722300000210
Figure FDA00033053722300000210
Figure FDA00033053722300000211
Figure FDA00033053722300000211
式中,
Figure FDA00033053722300000212
是流最大流速,
Figure FDA00033053722300000213
是严格的凸函数,
Figure FDA00033053722300000214
是时间t内Coflow等待队列的瓶颈因子;β表示Coflow流已发送大小与宽度的比值,虚拟队列中Coflow流的优先级与β相关,Coflow流已发送的数据越大,其数据本身大小也就越大,并且其宽度越小时,优先级越高;
Figure FDA00033053722300000215
是时间t内链路l中流f分配的带宽速率,
Figure FDA00033053722300000216
表示最大化Coflow效益;
In the formula,
Figure FDA00033053722300000212
is the maximum flow velocity,
Figure FDA00033053722300000213
is a strictly convex function,
Figure FDA00033053722300000214
is the bottleneck factor of the Coflow waiting queue in time t; β represents the ratio of the sent size to the width of the Coflow flow. The priority of the Coflow flow in the virtual queue is related to β. The larger the data sent by the Coflow flow, the larger the size of the data itself. The larger, and the smaller its width, the higher the priority;
Figure FDA00033053722300000215
is the bandwidth rate allocated by flow f in link l at time t,
Figure FDA00033053722300000216
Represents maximizing the Coflow benefit;
虚拟队列为:The virtual queue is:
Figure FDA00033053722300000217
Figure FDA00033053722300000217
式中,Ql(t)表示时间t内虚拟队列的长度,其与分配Coflow流的流速
Figure FDA00033053722300000218
以及链路带宽Bl直接相关,l表示第l条链路,L(l)表示总链路集合;
In the formula, Q l (t) represents the length of the virtual queue in time t, which is related to the flow rate of the allocated Coflow flow
Figure FDA00033053722300000218
And the link bandwidth B l is directly related, l represents the lth link, and L(l) represents the total link set;
采用Lyapunov漂移求解队列稳定性,得到期望流速如下:Using Lyapunov drift to solve the queue stability, the expected flow rate is obtained as follows:
Figure FDA0003305372230000031
Figure FDA0003305372230000031
求解出每条链路的最优解
Figure FDA0003305372230000032
以使Coflow完成时间取到最小;其中Ul(t)表示时间t内虚拟队列的总长度,rmax表示Lagrange优化取得的最大流速,其中V是一个非负参数,表示惩罚因子,会影响到最优目标函数值和满足期望约束所需的收敛时间之间的性能权衡。
Find the optimal solution for each link
Figure FDA0003305372230000032
In order to minimize the completion time of Coflow; where U l (t) represents the total length of the virtual queue in time t, r max represents the maximum flow rate obtained by Lagrange optimization, where V is a non-negative parameter, which represents the penalty factor, which will affect the A performance trade-off between optimal objective function value and convergence time required to satisfy desired constraints.
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Publication number Priority date Publication date Assignee Title
CN114666283A (en) * 2022-03-07 2022-06-24 国家电网有限公司信息通信分公司 An application-aware multi-tenant Coflow scheduling method and system
CN117221126A (en) * 2023-11-09 2023-12-12 之江实验室 Network collaboration flow-oriented route scheduling method and system

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN114666283A (en) * 2022-03-07 2022-06-24 国家电网有限公司信息通信分公司 An application-aware multi-tenant Coflow scheduling method and system
CN114666283B (en) * 2022-03-07 2023-11-24 国家电网有限公司信息通信分公司 An application-aware multi-tenant Coflow scheduling method and system
CN117221126A (en) * 2023-11-09 2023-12-12 之江实验室 Network collaboration flow-oriented route scheduling method and system
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