CN1900878A - Computer distribution type system time synchronous method - Google Patents

Abstract

A kind of computer distribution type system time synchronous method, comprising steps of calculating the delay time of computer A to B using the method that closed loop samples ; The delay time of computer A to B is calculated using the method that closed loop samples ; Calculate network delay

; And calculate the time TBi at the i moment of B. The advantage of the invention is that it is based on software realization, it is at low cost; Using the method for feedback sample, precision is high; Using computer temporal, realize simple.

Description

A kind of computer distribution type system time synchronous method

Invention field

The invention belongs to computer realm, relate generally to computer distribution type system time synchronous method etc.This technology mainly utilize the method for reaction type closed loop sampling realize with the school computer-chronograph time be benchmark, by network system when being undertaken, finally make by the time of school computer-chronograph and school computer-chronograph on the Millisecond precision, to reach consistent by the school computer-chronograph.

Background of invention

Since the nineties in 20th century, the development of computer hardware technology and software engineering, and the development of high performance computer network, cause the Distributed Calculation machine technology to develop rapidly, change the computed mode of people, made people that the pursuit of transparent access, high-performance and the high reliability target of computing power as much as possible, data is no longer a dream simultaneously.

In distributed computing system (abbreviation distributed system), many computing machines constitute a complete system, the similar one-of-a-kind system of its behavior.Be that how many platform machines the user needn't have in the understanding system, their position where, and what their function is, file where, and operation is in the details of the first-class any relevant hardware physical distribution of which platform machine.Wherein distributed operating system is to realize the core of distributed computing system.The characteristics of distributed computing system are as follows:

(1) system is made up of a plurality of processors or computer system;

(2) these computational resources can be physically adjacent, by the processor that machine intimate bus or switch connect, communicate by sharing main memory; These computational resources also can be separate geographically, by the computer system that computer communication network (telenet or LAN (Local Area Network)) connects, use message (Message) to communicate;

(3) these resources form a whole, and are transparent to the user, all where needn't know these resources when promptly the user uses any resource;

(4) programs can be distributed on each computational resource and move;

(5) each computer system is equal, except being subjected to system-wide operating system control, does not exist the principal and subordinate to control and the centralized control link.

Distributed computing system belongs to instruction stream multiple data stream (MIMD) structure.

The development of distributed computing system has also caused chronometer time, and the synchronous demand of split-second precision between system.Because chronometer time is the basic physical parameter of scientific research, scientific experiment and engineering aspects.Basis coordinates when measurement of its program process during for all and quantitative examination provide requisite.Its perfect linearity and continuity have shown the time of day of objective things.Its application is extensive, as information network, Aero-Space, navigation communication, electric power transfer and Scientific Measurement or the like numerous areas.

Method for synchronizing time commonly used is a clock synchronization, also is " to clock ", is meant that method is exactly a clock transportation the most intuitively the clock alignment (synchronously) that is distributed in various places, and an available standard clock is made clock transportation, and the clock of various places is aimed at standard clock.Clock transportation is at first aimed at the standard time clock of system, made other clock and comparison in the system then, other clock of realization system and systematic unity standard time clock are synchronous.Each clock is synchronous in the so-called system, and do not require that each clock is complete and the clock of seeking unity of standard is become a partner together, only require and know that each clock gets final product in comparison clock correction and its relative drift correction parameter to standard clock of comparison back constantly with the system standard clock, must not dial clock.The another kind of method of time synchronized is to use the radio wave propagation temporal information, promptly utilize radiowave to come the passing time standard, recover the corresponding time signal contrast of time signal by the time service type receiver then with local clock, deduct its time delay on travel path and the influence of various error components, realize the synchronous of clock.Along with improving constantly that clock synchronization accuracy is required, begin because the shortwave propagation path is subjected to the influence of ionosphere variation, to make time service precision only can reach the ms level with shortwave time service (ms) class precision with the method for radiowave time service.Developed into afterwards with myriameter waves and promptly use the time service of Omega platform, its time service precision is about about 10 microseconds, is that Loran-C station is taken into account time service with long wave again afterwards, and its time service precision can reach microsecond, but can't cover in the whole world.Developed into satellite clock again afterwards and did clock transportation, used the ultrashort wave propagation time signal, and received by the user and look certain satellite altogether, and made its time service precision can reach 10ns.Utilize the satellite time service can realize that the global range clock is synchronously accurate.

In addition, for computer network system, also has time system method at present based on Internet, it mainly is to use the main frame of " time service server ", produce precise time, generally produce by atomic clock, and use Internet internet, according to certain communication protocol, agreement commonly used has DayTime, Time and Simple Network Time agreement etc., need to insert the internet but have, and shortcoming, inapplicable security and the high distributed computing system of time precision requirement of precision low (generally can only arrive a second level).

For distributed computing system, split-second precision is its basal needs, also require high precision time unified simultaneously between each system of distributed computing system, therefore Time synchronization technique there is higher requirement, adoptable method has the gps clock method for synchronous in the clock synchronization mentioned above, this method has the characteristics strongly professional, that precision is high, but owing to need to be equipped with the GPS hardware device, also need rent gps satellite simultaneously, therefore this method is fit to have the catenet system of professional application background, and is not suitable for general distributed computing system.

Summary of the invention

In order to solve above-mentioned traditional problem, so one object of the present invention has proposed a kind of computer distribution type system time synchronous method exactly.

In one aspect of the invention, this computer distribution type system time synchronous method comprises step: (1) uses the method for closed loop sampling to calculate the delay time of computer A to B (2) use the method for closed loop sampling to calculate the delay time of computer A to B (3) computational grid time-delay D; And (4) calculate the i time T constantly of B _Bi

According to this aspect, the wherein said closed loop method of sampling is meant when computing machine B receives computer A behind the turnkey that sampling immediately deposits in the sampling buffer memory, and calculates turnkey when sending to A simultaneously, also does the same sampling operation of B after A receives.

According to this aspect, in step (1), $\stackrel{\‾}{D_A}=\frac{D_{A0}+D_{A1}+D_{A2}+\mathrm{\Λ}{+D}_{A(n-1)}}{n}$

According to this aspect, in step (2), $\stackrel{\&OverBar;}{D_B}=\frac{D_{B0}+{\mathrm{<figure-callout\; id="1"\; label="D\; B"\; filenames="A20061009069900071.png,A20061009069900072.png"\; state="\{\{state\}\}">D</figure-callout>}}_B+D_{B2}+\mathrm{\&Lambda;}+D_{B(n-1)}}{n}$

According to this aspect, in step (3), $\stackrel{\&OverBar;}{D}=\frac{\stackrel{\&OverBar;}{D_A}+\stackrel{\&OverBar;}{D_B}}{2}$

According to this aspect, in step (4), T _Bi=T _B0+ D+ Δ _Bi

Proposed by the invention during based on feedback principle soft the characteristics of system technology be: realize that based on software cost is low; Use the method for feedback sample, the precision height; Utilize computing machine self time, realize simple.

Description of drawings

In conjunction with accompanying drawing subsequently, what may be obvious that from following detailed description draws above-mentioned and other purpose of the present invention, feature and advantage.In the accompanying drawings:

Fig. 1 has provided according to closed loop sampling synoptic diagram of the present invention;

Fig. 2 has provided the work synoptic diagram according to computer distribution type system time synchronous method of the present invention;

Fig. 3 has provided according to time error curve of the present invention.

Embodiment

Split-second precision in the computer-chronograph of school is obtained in employing, calibrates the time that other needs the school computer-chronograph.The principle of close-loop feedback sampling realized the precise synchronization of time during this method utilization control was learned, and was implemented as follows:

1) A-time system service computer (school computer-chronograph);

System computing machine (by the school computer-chronograph) when 2) B-asks;

3) D _Ai-computer A is to the i of B delay time (comprise the time difference+i network delay constantly) constantly;

4) D _Bi-computing machine B is to the i of A delay time (comprise the time difference+i network delay constantly) constantly;

5)

-computer A is to the average delay time (comprising the time difference+A to the time-delay of B averaging network) of B;

6) -computing machine B is to the average delay time (comprising the time difference+B to the time-delay of A averaging network) of A;

7) the average delay time of D-computer A and B;

8) T _B0Zero moment of-computing machine B;

9) Δ _Bi-T _B0The time increment in the moment to the moment;

10) T _Bi-B computing machine i the time constantly;

11) a closed loop sampling: as mistake! Do not find Reference source.Shown in, refer to when computing machine B receives computer A behind the turnkey, immediately

Sampling (D that calculates this t moment comes) deposits in the sampling buffer memory, and while turnkey when A calculates transmission, also does the same sampling operation of B after A receives.

Below with reference to Fig. 2, the workflow according to computer distribution type system time synchronous method of the present invention is described in detail.

As mistake! Do not find Reference source.Shown in, use the method for closed loop sampling to calculate the delay time of computer A to B:

$\stackrel{\&OverBar;}{D_A}=\frac{D_{A0}+D_{A1}+D_{A2}+\mathrm{\&Lambda;}+D_{A(n-1)}}{n}$

Next, use the method for closed loop sampling to calculate the delay time of computer A to B:

$\stackrel{\&OverBar;}{D_B}=\frac{D_{B0}+D_{B1}+D_{B2}+\mathrm{\&Lambda;}+D_{B(n-1)}}{n}$

After this, computational grid time-delay D:

$\stackrel{\&OverBar;}{D}=\frac{\stackrel{\&OverBar;}{D_A}+\stackrel{\&OverBar;}{D_B}}{2}$

At last, calculate the i time T constantly of B _Bi:

T _Bi＝T _B0+ D+Δ _Bi

Utilize method as shown in Figure 2, the time when write down two computing machines behind the system, the time of record is carried out Error Calculation, and draw out graph of errors, analyze the precision of uniting when of the present invention.The time difference of record is drawn the time error curve, as mistake! Do not find Reference source.Shown in.

Two computers is behind out-of-date system as can be known by the time error curve, and two system time synchronization accuracies can reach hundred microsecond precision.

What may be obvious that for the person of ordinary skill of the art draws other advantages and modification.Therefore, the present invention with wider aspect is not limited to shown and described specifying and exemplary embodiment here.Therefore, under situation about not breaking away from, can make various modifications to it by the spirit and scope of claim and the defined general inventive concept of equivalents thereof subsequently.

Claims (6)

1, a kind of computer distribution type system time synchronous method comprises step:

(1) use the method for closed loop sampling to calculate the delay time of computer A to B

(2) use the method for closed loop sampling to calculate the delay time of computer A to B

(3) computational grid time-delay D; And

(4) the i time T constantly of calculating B _Bi

2, according to the process of claim 1 wherein that the described closed loop method of sampling is meant when computing machine B receives computer A behind the turnkey, sampling immediately deposits in the sampling buffer memory, and turnkey when A calculates transmission simultaneously, also does the same sampling operation of B after A receives.

3, according to the process of claim 1 wherein in step (1):

$\stackrel{\&OverBar;}{D_A}=\frac{D_{A0}+D_{A1}+D_{A2}+\mathrm{\&Lambda;}+D_{A(n-1)}}{n}.$

4, according to the process of claim 1 wherein in step (2):

$\stackrel{\&OverBar;}{D_B}=\frac{D_{B0}+D_{B1}+D_{B2}+\mathrm{\&Lambda;}+D_{B(n-1)}}{n}.$

5, according to the process of claim 1 wherein in step (3):

$\stackrel{\&OverBar;}{D}=\frac{\stackrel{\&OverBar;}{D_A}+\stackrel{\&OverBar;}{D_B}}{2}.$

6, according to the process of claim 1 wherein in step (4):

T _Bi＝T _B0+ D+Δ _Bi。

Images