JP3233073B2 - Disk access method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a disk access system, and more particularly to an access system suitable for use in multimedia data disk access.

[0002]

2. Description of the Related Art In a conventional disk access system, a disk driver sequentially processes an I / O request (input / output request) from an application (referred to as an "AP"). That is, as shown in FIG. 3, an I / O request from the AP 1 is placed in an I / O request queue 2-2 in the disk driver 2-1.

The disk driver 2-1 fetches one head of the I / O request stored in the I / O request queue 2-2 and, based on the content of the fetched I / O request, writes the head of the I / O request to the disk 3-1. , Issues an I / O request in I / O block units.

When the I / O operation is completed, the disk driver 2-1 notifies the AP 1 of the completion of the I / O, and the next I / O queue queued in the I / O request queue 2-2. The O request is taken out and the processing is performed.

[0005]

In the above-described conventional disk access method, the problem that the I / O block length cannot be increased even when a large amount of data such as moving image data is stored on the disk. Have a point.

The reason is that, for sequential I / O processing, if the I / O block length is increased, a later incoming high priority I / O request will wait for a long time. . That is, I / O of high bit rate data such as moving image data on a disk
In the processing, if the I / O block length is increased, the I / O efficiency increases, but when a high-priority I / O request occurs,
Waiting is completed until I / O of a long block length currently being processed is completed, and the response characteristics are degraded.

Accordingly, the present invention has been made in view of the above-mentioned problems, and has as its object to improve the I / O performance even when the I / O block length is increased. An object of the present invention is to provide a disk access method that can process an I / O request by interrupting the I / O request in the middle of a normal I / O request.

[0008]

Means for Solving the Problems] To achieve the above object, a disk access method of the present invention, a disk dry
When processing a normal priority I / O request,
I / O request unit from application (AP)
I / O block of disk, not unit of O block
In the unit of the I / O sub-block which is a unit obtained by dividing
Issue an I / O to the disk and request the high priority I / O request
I / O is a length composed of a plurality of the I / O sub-blocks.
Performed sequentially in I / O block units
And the disk driver normally receives the priority I / O request .
During processing, if a high priority I / O request occurs,
A means for interrupting the high-priority I / O request at a break of the O sub-block and processing the interrupt first is provided .

Further, the disk access method of the present invention
Preferably, an I / O for queuing input / output requests (referred to as "I / O requests") from an application (AP)
The request queue includes a normal priority I / O request queue and a high priority I / O request queue.
The disk I / O request from P is queued in an I / O request queue according to the priority of the I / O request, and the disk driver sends a request to the high priority I / O request queue and the normal priority I / O request queue. I in order
If a high priority I / O request occurs while processing an I / O request and processing an I / O request in the normal priority I / O request queue, the normal priority I / O
The I / O sub-block, which is a unit obtained by dividing the requested I / O block, is interrupted and processed first.

[0010]

Embodiments of the present invention will be described below. In a preferred embodiment of the present invention, the disk driver (2-1 in FIG. 1) has an I / O request queue for queuing I / O requests from the application (AP) (1 in FIG. 1). It has a normal priority I / O request queue (2-2 in FIG. 1) and a high priority I / O request queue (2-3 in FIG. 1). The disk I / O request from the AP is queued in an I / O request queue according to the priority of the I / O request.

The disk driver has a high priority,
I / O requests are processed in the order of the normal priority I / O request queue. If a high-priority I / O request occurs while processing an I / O request in the normal priority I / O request queue, the normal priority I / O request queue is processed. An I / O sub-block which is a unit obtained by dividing the I / O block of the O request (FIG. 1)
The interrupt is processed at the break in 3-3).

According to the embodiment of the present invention, even when the I / O block length is increased to improve the I / O performance,
A high-priority I / O request can be processed by being interrupted in the middle of a normal I / O request. Therefore, when a large amount of data such as moving image data is stored on a disk, the I / O request is processed. Since the block length can be increased, an effect of improving the I / O throughput can be obtained.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention;

FIG. 1 is a block diagram showing one embodiment of the disk access system of the present invention. The disk access method according to the present embodiment uses an application (referred to as “AP”).
1, a disk driver 2-1 and a disk device 3-1. The disk driver 2-1 has a normal priority I
An I / O request queue 2-1 and a high priority I / O request queue 2-2 are provided.
-2, an I / O sub-block 3-3.

FIG. 2 is a flowchart showing the operation of the disk driver 2-1 according to one embodiment of the present invention.

The AP 1 requests I / O processing of the disk 3-1 through the disk driver 2-1. This I / O
In the case of a request, a normal priority or a high priority is specified as an I / O priority.

The disk driver 2-1 queues an I / O request from the AP 1 in an I / O request queue according to the priority, that is, a normal priority I / O request queue and a high priority I / O request queue.

The disk driver 2-1 has a disk 3-
If there is no I / O request to the I / O request 1, there is no unprocessed I / O request in the order of the high priority I / O request queue 2-3 and the normal priority I / O request queue 2-2. Is checked (step S).

High priority I / O request queue 2-3
If there is an unprocessed I / O request (YES branch of step S2 in FIG. 2), the I / O request corresponding to this I / O request
/ O is issued to the disk 3-1 (step S3). In this case, the unit of the I / O is the I / O block 3-2 (see FIG. 1) requested by the AP1.

When the I / O is completed on the disk 3-1, the disk driver 2-1 removes the I / O request from the high priority I / O request queue 2-3 and sends the I / O request to the AP1.
It is notified as / O completion (step S4 in FIG. 2).

When there is no I / O request in the high priority I / O request queue 2-3, the disk driver 2-1 sends the normal priority I / O request queue 2-2.
If the I / O request exists in the normal priority I / O request queue 2-2 (YE in step S5 in FIG. 2)
(S branch), and issues an I / O corresponding to the I / O request to the disk 3-1. In this case, the I / O issuance to the disk 3-1 is not performed in the unit of the I / O block 3-2, which is the unit of the I / O request from the AP1, but in the unit of the divided I / O sub-block 3-3. (Step S6).

I / O of first I / O sub-block 3-3
Is completed, the disk driver 2-1 checks the high-priority I / O request queue 2-3, and if no I / O request is queued here, the immediately following I / O request is continued.
I / O is issued for the / O sub-block 3-3 (step S9 in FIG. 2).

Since the I / O sub-block 3-3 is physically continuous with the previously completed I / O sub-block 3-3, no I / O activation wait due to the seek operation of the disk 3-1 occurs. .

When data is read from the disk 3-1, the disk 3-1 normally pre-reads in a built-in cache memory, so that there is no waiting for I / O activation due to the rotation of the disk 3-1. That is, data reading of the physically continuous I / O sub-block 3-3 waits for a seek operation and disk rotation unless another I / O request is received between I / O sub-blocks. Instead of being executed immediately.

When the I / O of all the I / O sub-blocks 3-3 constituting the I / O block 3-2 is completed, the disk driver 2-1 sends the normal priority I / O request queue 2 -2, remove I / O request,
Notify AP1 as I / O completion (Step S in FIG. 2)
10).

On the other hand, while the disk driver 2-1 is executing the normal priority I / O in units of the I / O sub-block 3-3, the high priority I / O request queue 2-3
When an I / O request is received from the AP 1 (YES branch of step S8 in FIG. 2), the disk driver 2-1
Processes I / O requests of normal priority,
Processing is interrupted at a break in the sub-block 3-3, and a high priority I / O request is processed first (steps S11 and S1).
2).

When the high-priority I / O is completed, the I / O is interrupted in the interrupted I / O sub-block unit 3-3.
O is maintained (step S9 in FIG. 2).

[0028]

As described above, according to the present invention,
For example, when a large amount of data such as moving image data is stored on a disk, the I / O block length can be increased, so that the I / O throughput can be increased.

The reason is that, in the present invention, even if the I / O block length is set to be large, the high priority I / O block is used.
When a request occurs, I / O processing can be executed by interrupting this high-priority I / O at a break of an I / O sub-block which is a unit of dividing the I / O block.
It depends on what you do.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of the disk driver according to one embodiment of the present invention.

FIG. 3 is a block diagram showing an example of a configuration of a conventional disk access method.

[Explanation of symbols]

1 AP (Application Program) 2-1 Disk Driver 2-2 Normal Priority I / O Request Queue, I / O
Request queue 2-3 High priority I / O request queue 3-1 Disk 3-2 I / O block 3-3 I / O sub-block

Claims (3)

(57) [Claims] 1. A disk driver usually has a priority I / O request.
In processing the request, from the application (AP)
It is not a unit of I / O block which is a unit of I / O request.
In addition, I, which is a unit obtained by dividing an I / O block of a disk,
Issue I / O to the disk in units of / O sub-blocks
And the I / O of the high priority I / O request comprises a plurality of I / Os.
I / O block unit having a length composed of sub-blocks
The disk driver processes a normal priority I / O request .
When a high-priority I / O request is generated, a means is provided for interrupting the high-priority I / O request at a break between I / O sub-blocks and performing processing first.
That, the disk access method, characterized in that. 2. A disk driver receives an input / output request ("I / O request") from an application ("AP").
) As an I / O request queue for queuing
A normal priority I / O request queue and a high priority I / O request queue are provided, and the disk I / O request from the AP responds to the priority of the I / O request in accordance with the normal priority I / O request.
Queued in a queue or a high priority I / O request queue, wherein the disk driver
The I / O request is processed in the order of the request queue and the normal priority I / O request queue, and the disk driver processes the normal priority I / O request.
Issue I / O to disk corresponding to I / O request of request queue
When executing, it is a unit of I / O request from the AP
Divide I / O block instead of I / O block unit
The I / O sub-block is a unit of I / O
Issue an O and send a normal priority I / O request to the I / O sub-block.
Running the unit, the high priority I / O request queue
When an I / O request is received from the AP,
Processing of priority I / O requests is handled by the I / O sub-block.
I / O requests with high priority
The by interrupting the process before, I of the high priority
When I / O is completed, the suspended I / O sub-block
A disk access method comprising means for issuing I / Os at different levels. 3. The normal driver according to claim 1 , wherein
For processing I / O requests in the priority I / O request queue
When the I / O of the I / O sub-block is completed,
Examine the priority I / O request queue and find the I / O
If the request is not queued, continue immediately
Issue I / Os for I / O sub-blocks and
I of all I / O sub-blocks constituting the I / O block
When / O is completed, the normal priority I / O request
Remove the I / O request from the queue and send the I / O completion to the AP.
Means for performing control for notifying that the
3. The disk access method according to claim 2, wherein