JP7265403B2 - NETWORK DELAY MEASUREMENT METHOD AND APPARATUS AND PROGRAM - Google Patents

Description

The present invention relates to network delay measurement, and more particularly to technology for measuring packet processing delay in a computer.

Conventionally, with regard to techniques for measuring network delays, active and passive network delay measurement techniques have been proposed as techniques that can be used even in non-virtualized environments (see Patent Literatures 1 and 2).

The technique described in Patent Document 1 is an active network delay measurement technique. In Patent Document 1, as shown in FIG. 5A, a test packet generation device 1 generates test packets separately from packets related to main signals, and applies them to a network 2 . For example, PING can be used as a test packet protocol. The test packet reaches the test packet receiving device 3 via the network, that is, via the packet transfer device 2 that constitutes the network. The test packet generation device 1 and the test packet reception device 3 record a time stamp at the time of transmission or reception of the test packet, and transmit it to the delay calculation device 4 as quality information. The delay calculator 5 estimates the network delay based on the time stamp difference or the like.

The technique described in Patent Document 2 is a passive network delay measurement technique. In Patent Document 2, as shown in FIG. 5(b), a delay estimating device 11 collects specific information (eg, 5-tuple, etc.) of a packet related to a main signal from each packet transfer device 12. , determine the cause of quality deterioration such as delay from the obtained statistical information.

JP 2002-118586 A JP 2006-246118 A

However, the methods described in Patent Documents 1 and 2 measure the transfer delay of packets in a network. In other words, it measures the packet transfer delay between packet transfer devices.

On the other hand, as network delay measurement, there is a demand to grasp not only the delay occurring between packet transfer devices but also where the delay occurs within the packet transfer device. In particular, in recent years, it has become common to virtualize packet transfer equipment due to the development of server virtualization technology. There is a desire to understand in detail the On the other hand, as described above, the devices described in Patent Documents 1 and 2 have the problem that such delay measurement within the packet transfer device cannot be performed.

In addition, the technique described in Patent Document 1 has the problem of unnecessarily consuming network resources because test packets are applied to the network.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and its first object is to measure the delay in packet processing within a computer without imposing a load on the network. A second object is to measure packet processing delays in a computer in which a virtual environment is built.

In order to achieve the above object, the present invention comprises a virtual environment building unit that is connected to a network and builds a virtual environment on hardware, and a virtual computer built by the virtual environment building unit . a network delay measurement method for measuring a delay due to packet processing in a computer in which the virtual environment construction unit and the virtual computer each have a packet processing function unit and a timer function unit , wherein the virtual environment construction unit storing the time information measured by the clock function unit of the virtual environment construction unit in a memory that can be referenced from the virtual computer; and the time synchronization provided in the virtual computer. a functional unit synchronizing the clock function unit of the virtual computer with the clock function unit of the virtual environment construction unit by referring to the time information in the memory; Each of the processing function unit and the packet processing function unit of the virtual computer includes identification information of the packet and identification information of the delay measurement point when a packet processing event occurs at a plurality of predetermined delay measurement points within itself . a step of generating event information; and event information generated by the packet processing function unit provided in the virtual environment construction unit and the time stamp addition function unit provided in the virtual computer, respectively. a step of giving a time stamp based on time information clocked by the clock function unit of itself , and a delay calculation function unit provided in the virtual environment construction unit or the virtual computer , the virtual environment construction unit and calculating a delay time between delay measurement points based on a plurality of event information about the same packet to which a time stamp has been added by the time stamping function unit of and the time stamping function unit of the virtual computer. characterized by

Further, the present invention is connected to a network and includes a virtual environment construction unit that constructs a virtual environment on hardware; and a virtual computer constructed by the virtual environment construction unit. The environment construction unit and the virtual computer are network delay measurement devices for measuring delay due to packet processing in a computer having a packet processing function unit and a timer function unit, respectively. a time synchronization function unit that stores time information clocked by the clock function unit of the virtual environment construction unit on a memory that can be referenced from a computer; and a time synchronization function unit for synchronizing the time measurement function unit of the virtual computer and the time measurement function unit of the virtual environment construction unit, and the packet processing function unit of the virtual environment construction unit and the virtual computer When a packet processing event occurs at a plurality of predetermined delay measurement points within each of the packet processing function units, the packet processing function unit generates event information including identification information of the packet and identification information of the delay measurement points, and the network The delay measurement device is further provided in the virtual environment construction unit and the virtual computer, and measures time information measured by the timer function unit of the event information generated by the packet processing function unit of the respective devices. and a time stamping function unit provided in the virtual environment building unit or the virtual computer, the time stamping function unit of the virtual environment building unit and the time stamping of the virtual computer and a delay calculation function unit that calculates a delay time between delay measurement points based on a plurality of event information about the same packet to which the time stamp is added by the function unit.

According to the present invention, the delay time between a plurality of delay measurement points set in the computer can be calculated, so the packet processing delay in the computer can be measured without imposing a load on the network. Also, even in a virtual environment, it is possible to calculate a delay in each of the virtual environment construction unit and the virtual computer and a delay time between them. Here, since the time is synchronized between the virtual environment building unit and the virtual computer, it is possible to accurately measure the delay in the virtual environment.

Diagram explaining the outline of the network delay measurement method Functional block diagram of network delay measurement device Flowchart for explaining delay measurement processing of the network delay measurement device Functional block diagram of a network delay measurement device according to another example Diagram explaining conventional network delay measurement

First, an overview of a network delay measurement device and method according to an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram explaining an outline of a network delay measurement method according to one embodiment of the present invention.

As shown on the left side of FIG. 1, the present invention captures the occurrence of a packet processing event in the kernel or the like of a computer with a virtualized environment, records the time stamp of each packet when the event occurs, and measures the delay. The time stamp difference between points calculates the network delay in the computer.

In addition, as shown on the right side of FIG. 1, the present invention provides high-speed Host/Guest communication via a shared memory between Host/Guest in order to accurately measure network delay in a packet processing route section that straddles Host/Guest. Synchronize time between

Next, details of a network delay measuring device and method according to an embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a functional block diagram of the network delay measuring device.

As shown in FIG. 2, the network delay measurement device 100 has a virtual environment configured as a virtual machine (VM) on a computer, which is physical hardware. First, as a premise of the present invention, the configuration of the network delay measurement device 100 and the configuration of the virtual environment will be described. Note that only the configuration related to the gist of the present invention will be described here.

The physical hardware 110 of the network delay measurement device 100 includes at least one physical network interface unit, NIC 111, and a physical timekeeping function unit 112, which is clock-related physical hardware such as hwclock and TSC (Time Stamp Counter). and

A HostOS 120 is installed in the physical hardware 110 . The type of HostOS is irrelevant. In this embodiment, Linux (registered trademark) is used as the HostOS 120 . As standard functions, the HostOS 120 refers to a packet processing function unit 121 that provides packet transmission or reception processing via the NIC 111 to an application on the HostOS 120, and a physical timer function unit 112, or resets the clock by interrupt processing. It has a host system clock 122 which is a clocking function unit. In Linux (registered trademark) used in this embodiment, the standard function of the packet processing function unit 121 and the function of the host system clock 122 are implemented in the kernel.

A Hypervisor 130 that is application software for building a virtual environment is installed on the HostOS 120 . Hypervisor 130 builds one or more VMs 140 . FIG. 2 shows an example in which two VMs 140 are constructed. VM140 constructed|assembled by Hypervisor130 is provided with vNIC141 which is one or more virtual network interface parts at least.

A GuestOS 150 is installed in the VM 140 . The GuestOS 150 may be of the same type as the HostOS 120, or may be of a different type. In this embodiment, the GuestOS 150 is the same Linux (registered trademark) as the HostOS 120 .

The GuestOS 150 has, as standard functions, a packet processing function unit 151 that provides packet transmission or reception processing via the vNIC 141 to the application 200 on the GuestOS 150, and a Guest system clock 152 that is a timing function unit that keeps a clock by interrupt processing. It has In Linux (registered trademark) used in this embodiment, the standard function of the packet processing function unit 151 and the function of the host system clock 152 are implemented in the kernel.

As described above, the network delay measurement device 100 includes the HostOS 120 and the Hypervisor 130 as virtual environment construction units on the physical hardware 110, and the VM 140 and GuestOS 150 as virtual computers constructed by the virtual environment construction unit. . The network delay measurement device 100 according to the present embodiment has the following features on the premise of such a virtualized environment.

In addition to the above-described standard packet transmission/reception processing function, the Host packet processing function unit 121 of the HostOS 120, when a packet processing event occurs (eg, arrival of a packet, etc.) at a preset delay measurement point within itself, , acquires the identification information of the packet (eg, 5-tuple), generates event information including the identification information of the packet and the identification information of the delay measurement point (eg, the name of the delay measurement point), Host It has a function of notifying the time stamp adding function unit 123 .

Similarly, the Guest packet processing function unit 151 of the Guest OS 150, in addition to the standard packet transmission/reception processing function described above, generates a packet processing event (eg, arrival of a packet, etc.) at a preset delay measurement point within itself. At that time, obtain the identification information of the packet, generate the event information including the identification information of the packet (e.g. 5-tuple) and the identification information of the delay measurement point (e.g. delay measurement point name), It has a function of notifying the Guest time stamp adding function unit 153, which will be described later.

Here, the host packet processing function unit 121 and the guest packet processing function unit 151 may detect the occurrence of a packet processing event in either or both of the ingress and egress directions. Also, the target packets may be all packets, or may be limited to those satisfying a predetermined condition. Here, the predetermined conditions are, for example, packet destination or source address or address range, destination or source port number or port number range, upper layer information (for example, information indicating type such as TCP or UDP), any of these A combination of

Various means can be used as a method for detecting the occurrence of a packet processing event in the Host packet processing function unit 121 and the Guest packet processing function unit 151 . For example, for Linux (registered trademark), kprobe can be used.

At least two delay measurement points are set in the HostOS 120 and the GuestOS 150 in the entire network delay measurement device 100 . By setting a plurality of delay measurement points inside the Host packet processing function unit 121 or the Guest packet processing function unit 151 , it is possible to measure the processing delay inside the Host OS 120 or Guest OS 150 . Also, by setting delay measurement points in both the Host packet processing function unit 121 and the Guest packet processing function unit 151, the processing delay between the HostOS 120 and the Guest OS 150 can be measured. Also, when a plurality of VMs 140 and GuestOS 150 are built in the network delay measurement device 100, the processing delay between each GuestOS 150 can be measured. In this manner, by setting the delay measurement point at an appropriate position according to the purpose of delay measurement, etc., the delay can be measured at any position within the network delay measurement device 100 .

As a policy for setting the delay measurement points, it is preferable to set the intervals between the delay measurement points to be as wide as possible from when the packet enters the HostOS 120 or GuestOS 150 until it leaves, because the delay can be measured comprehensively. . That is, the closer the delay measurement point is to the entrance and the closer to the exit, the better.

By the way, the Host packet processing function unit 121 and the Guest packet processing function unit 151 are generally configured to be processed by a series of processing units through which packets are distributed. It is preferable to set the delay measurement point at a point between these processing units. This is because even if a plurality of delay measurement points are provided within the same processing unit, the delay does not occur much and the measurement is not meaningful in many cases.

In this embodiment, two delay measurement points are set for the Host packet processing function unit 121 and two points for the Guest packet processing function unit 151 in the ingress direction (direction from outside the network delay measurement device 100 toward the application 200). bottom. In the ingress direction (the direction from the application 200 to the outside of the network delay measurement device 100), three delay measurement points are set for the Host packet processing function unit 121 and three points for the Guest packet processing function unit 151. FIG.

The HostOS 120 includes a Host time stamping function unit 123, as shown in FIG. When acquiring event information from the host packet processing function unit 121, the host time stamping function unit 123 acquires clock information from the host system clock 122 as a time stamp (for example, in the case of Linux (registered trademark), CLOCK_MONOTONIC, etc.). The information and the time stamp are linked, and the information consisting of [packet identification information, time stamp, measurement point identification information] is held and notified to the delay calculation function unit 124, which will be described later.

Similarly, the GuestOS 150 has a Guest timestamp addition function unit 153 . When acquiring event information from the Guest packet processing function unit 151, the Guest time stamping function unit 153 acquires clock information (for example, CLOCK_MONOTONIC in the case of Linux (registered trademark)) from the host system clock 122 as a time stamp, and processes the event. The information and the time stamp are linked, and the information consisting of [packet identification information, time stamp, measurement point identification information] is held and notified to the delay calculation function unit 124, which will be described later.

In the case of Linux (registered trademark), event occurrence capture and event information generation processing in the packet processing function unit 121 of the HostOS 120, and processing in the timestamp addition function unit 123 are implemented as eBPF (extended Berkeley Packet Filter) bytecode. Then, it can be executed without rebuilding the kernel. The same applies to the GuestOS 150 as well.

The HostOS 120 further has a delay calculation function unit 124 . The delay calculation function unit 124 converts information consisting of [packet identification information, time stamp, measurement point identification information] received from the Host timestamp addition function unit 123 and the Guest timestamp addition function unit 123 into an information group in the form of an array or the like. is stored in a predetermined storage means. As storage means, it is desirable to store in a memory space or the like because of high speed. The delay calculation function unit 124 calculates the network delay between the delay measurement points by calculating the time difference of the time stamps between the delay measurement points for the same packet identification information based on the information group. The calculated network delay can be stored in a predetermined storage means or transmitted to another device.

Delay measurement processing of the network delay measurement device 100 according to this embodiment will be described with reference to the flowchart of FIG.

When the host packet processing function unit 121 and the guest packet processing function unit 151 respectively detect the occurrence of packet processing at a delay measurement point (step S101), they generate event information including identification information of the packet and identification information of the delay measurement point. (step S102). The Host time stamp adding function unit 123 and the Guest time stamp adding function unit 123 add time stamps to each piece of event information (Step S103). Then, the delay calculation function unit 124 calculates the delay between the delay measurement points for the same packet based on multiple pieces of event information (step S104).

In the present invention, it is preferable that the timestamp added by the Host timestamp adding function unit 123 and the timestamp added by the Guest timestamp adding function unit 153 are synchronized with high accuracy.

Therefore, in the network delay measuring device 100 according to the present embodiment, as shown in FIG. 2, the Host OS 120 is provided with the Host time synchronization function unit 125 and the Guest OS 150 is provided with the Guest time synchronization function unit 155 .

The host time synchronization function unit 125 saves clock information kept by the host system clock 122 on shared memory that can be referenced from the VM 140 . The Guest time synchronization function unit 155 refers to the clock information saved by the Host time synchronization function unit 125 from the shared memory. Then, the Guest time synchronization function unit 155 notifies the Guest system clock 152 of the synchronization time. Thereby, the Host system clock 122 of the HostOS 120 and the Guest system clock 152 of the GuestOS 150 are synchronized with high precision. Thus, in this embodiment, unlike time synchronization via a network such as ntp, synchronization processing is performed via a shared memory, so high-speed time synchronization is possible.

As described in detail above, the network delay measurement device 100 according to the present embodiment makes it possible to measure the network delay within a computer in a virtualized environment. In particular, this delay measurement can be performed by communication of the main signal without impressing the test packet, so unnecessary consumption of network resources can be suppressed. In addition, according to the network delay measurement device 100 according to the present embodiment, the network delay is measured for each packet, and it is possible to measure the network delay for all packets. It becomes possible.

Moreover, according to the network delay measuring device 100 according to the present embodiment, it is possible to measure the network delay in the section where the Host/Guest straddles with high accuracy. Further, according to the network delay measurement device 100 according to the present embodiment, it is possible to measure the network delay within the Host and within the Guest with high accuracy.

Although one embodiment of the present invention has been described in detail above, the present invention is not limited to the above-described embodiment, and various improvements and modifications may be made without departing from the gist of the present invention. .

For example, in the above embodiment, the delay calculation function unit 124 is provided in the HostOS 120, but the mounting position is irrelevant. For example, it may be provided in the GuestOS 150 or may be provided in another device.

Further, in the above-described embodiment, the host OS type is exemplified as a mode for constructing a VM-configured virtualization environment, but a hypervisor type virtualization environment that does not require a host OS may also be used. In this case, we install the hypervisor application directly on the physical hardware. Then, the hypervisor application may be configured with a packet processing function unit, a time stamping function unit, and a time synchronization unit similar to those in the above embodiment.

In addition, in the above-described embodiment, a VM-configured virtualization environment was constructed, but the present invention can also be implemented in a container-type virtualization environment. In this case, although the packet delay cannot be measured within the container, the same packet delay measurement technique as in the above embodiment can be applied to the HostOS. However, since Guest OS does not exist, the time synchronization function is unnecessary. FIG. 4 shows a functional block diagram of the network delay measurement device 100' in the case of a container type virtual environment. As shown in FIG. 4, the configuration below the HostOS 120 is the same as in the above embodiment. The HostOS 120 is installed with a container engine 160, which is a container environment construction unit. A container 170 is formed on the container engine 160, and the application 200 in the container 170 operates. Note that since FIG. 4 is a functional block diagram focusing on the hierarchical structure, the application 200 is shown outside (above) the container 170 .

Further, in the above embodiments, the virtual environment was constructed on the computer, but the present invention can be implemented even if the virtual environment is not constructed. In this case, an OS having packet delay measurement technology similar to the HostOS in the above embodiment should be installed in the computer. However, since Guest OS does not exist, the time synchronization function is unnecessary.

DESCRIPTION OF SYMBOLS 100... Network delay measuring device 110... Physical hardware 111... NIC
112... Physical clock function unit 120... Host OS
121 Host packet processing function unit 122 Host system clock
123 Host timestamp addition function unit 124 Delay calculation function unit 125 Host time synchronization function unit 150 Guest OS
151 Guest packet processing function unit 152 Guest system clock
153 Guest timestamp addition function unit 155 Guest time synchronization function unit 200 Application

Claims (6)

a virtual environment construction unit connected to a network and constructing a virtual environment on hardware; and a virtual computer constructed by the virtual environment construction unit. A network delay measurement method for measuring a delay due to packet processing in a computer each having a packet processing function unit and a timer function unit ,
a step in which the time synchronization function unit provided in the virtual environment construction unit saves time information clocked by the clock function unit of the virtual environment construction unit in a memory that can be referenced from the virtual computer;
a step in which the time synchronization function unit provided in the virtual computer synchronizes the time measurement function unit of the virtual computer with the time measurement function unit of the virtual environment construction unit by referring to the time information in the memory;
Identification information of the packet when the packet processing function unit of the virtual environment construction unit and the packet processing function unit of the virtual computer each generate a packet processing event at a plurality of predetermined delay measurement points within itself and generating event information including identification information of the delay measurement point;
The time-stamping function unit provided in the virtualization environment building unit and the time-stamping function unit provided in the virtual computer have their own time-counting functions for the event information generated by their respective packet processing function units. a step of adding a time stamp based on the time information clocked by the unit ;
The delay calculation function unit provided in the virtual environment construction unit or the virtual computer is provided with a time stamp by the time stamp addition function unit of the virtual environment construction unit and the time stamp addition function unit of the virtual computer. and calculating a delay time between delay measurement points based on a plurality of event information for the same packet. 2. The network delay measurement method according to claim 1, wherein said delay calculation function unit is provided in said virtual environment construction unit. 2. The network delay measuring method according to claim 1 , wherein said packet processing function unit is provided inside a kernel of said virtual environment construction unit, and said packet processing function unit is provided inside said kernel of said virtual computer. The packet processing function unit is configured to be processed by a series of processing units through which packets are distributed,
4. The network delay measurement method according to claim 1, wherein said delay measurement point is set between said plurality of processing units. a virtual environment construction unit connected to a network and constructing a virtual environment on hardware; and a virtual computer constructed by the virtual environment construction unit. The computer is a network delay measuring device for measuring delay due to packet processing in a computer having a packet processing function unit and a timer function unit ,
a time synchronization function unit that is provided in the virtual environment construction unit and saves time information clocked by the clock function unit of the virtual environment construction unit in a memory that can be referenced from the virtual computer;
a time synchronization function unit provided in the virtual computer and synchronizing the time function unit of the virtual computer and the time function unit of the virtual environment building unit by referring to the time information in the memory;
The packet processing function unit of the virtual environment construction unit and the packet processing function unit of the virtual computer each generate identification information of the packet when a packet processing event occurs at a plurality of predetermined delay measurement points within itself. and generate event information including identification information of the delay measurement point,
The network delay measurement device further
Provided in the virtual environment construction unit and the virtual computer, and giving a time stamp to the event information generated by the packet processing function unit thereof, based on the time information clocked by the clock function unit thereof. a time stamping function unit;
About the same packet provided in the virtual environment building unit or the virtual computer and given a time stamp by the time stamping function unit of the virtual environment building unit and the time stamping function unit of the virtual computer A network delay measurement device, comprising: a delay calculation function unit that calculates a delay time between delay measurement points based on a plurality of event information. A program that causes a computer to function as each part of the network delay measurement device according to claim 5 .

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