JPS6034144B2 - Locking method for storage device access - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for accessing a common area in a storage device from multiple processing devices, and in particular, when a specific processing device is accessing the common area using a lock function, other processing devices may access the common area. The present invention relates to a method for minimizing interruptions in access to a storage device by a specific processing device when the common area is accessed by a specific processing device using a lock function.

In the conventional method, when processing device 1 uses a lock instruction to access a common area in main memory, when another processing device wants to access the common area using the lock function, the lock instruction is used to access the common area. When the recognition word in memory is read and its contents are decoded and it is learned that the processing device 1 is in use, branch instructions and lock instructions are executed until the processing device 1 rewrites the recognition word and releases the lock function. It was running a loop.

However, with this method, each time another processing device issues a lock command, the main memory suspends access from processing device 1 and accepts access to send the recognition word to the other processing device. , there is a drawback that access of the processing device 1 is interrupted each time. The purpose of the present invention is to
The purpose of this is to minimize access interruptions due to lock commands issued by programs of other CPUs when a program of CPU-1 uses the lock function to access a common area on main memory. This technology takes advantage of the characteristics of a store-through type buffer storage device.

The purpose of this is to provide an information processing system consisting of a plurality of processing units each having a store-through type buffer storage device, in which a common area commonly used by the plurality of processing units exists in the main storage unit, and in which a specific processing When the device locks and uses a common area on the main storage device, reads the recognition word in the main storage device using a lock access instruction and confirms that it is not locked by another processing device;
Rewriting the recognition word to a locked state - In a locking method for accessing a storage device, each processing unit is provided with a storage means for storing that a lock access is in progress, and when the recognition word is issued when the lock access command is issued, ,
When indicating that the recognition word or the memory block containing the recognition word is locked by another processing device, the recognition word or the memory block containing the recognition word is stored in a buffer storage device, and the recognition word or the memory block containing the recognition word is stored from the other processing device. This is achieved by a storage device access locking method characterized in that when the invalidation is notified, a lock access command is issued again based on the contents of the storage means. Here, to help understand the present invention, a store-through type buffer storage device will be explained.

Multiple processing units serve as main memory (some common areas may be used)
are used in common, and each processing device has a buffer storage device, and when a specific processing device rewrites the contents of the main storage device, the other processing device writes the contents of the storage location (memory block) to be rewritten. If the data is being imported into its own buffer storage device, the specific processing device notifies the other processing device of the invalidation of the memory location (memory block) to be rewritten, and the other processing device shares the buffer storage device with the main one. This prevents discrepancies in the contents of the storage device. This is called matching processing in a store-through type buffer storage device. The present invention takes advantage of the characteristics of this store-through type buffer storage device, and stores a recognition word or a memory file containing the recognition word when lock accessing a common area.

When it is found by the lock that another processing device is locking and using the common area, the recognition word (memory block containing the recognition word) is stored in the buffer storage device,
By issuing a lock access command again upon receiving invalidation notification of the recognition word (or memory block) from another processing device, the lock access command in use can be canceled without the loop of lock access commands and branch commands in the conventional method. Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is a block diagram of the present invention.

In the figure, 11 is CPU-1, 12 is buffer storage 1
, 13 is the CPU-2, 14 is the buffer storage device 2, 15
is BIC (buffer invalidation mechanism), 16 is recognition word,
17 is a main memory, 18 is a common area, 19 is stored address information, and 11 is a buffer invalidation signal. FIG. 2 is a diagram showing an operation time chart of the present invention.

In the figure, 21 is ACLOOK (lock access instruction), 22 is BR (branch instruction), and 24 is LO
OK (lock request), 25 is a virtual lock (not actually locked), 26 is LKMSR (fetch from main memory by lock access, that is, access from other CPUs is prohibited during this period), 27 is BSR (data fetch from buffer storage), 28 is MOV (data fetch from main memory), and 29 is UNS (indicates that the lock request was not successful).

) 21 indicates BSW (timing to store data from the main memory to the buffer memory), 211 indicates INTLK (sets information to the flip-flop circuit), and 212 indicates prohibition of access to the main memory. The operation will be explained below using the embodiment shown in FIG.

Now, when the program of the processing unit (hereinafter abbreviated as CPU) 1 1 accesses the common area 18 in the main storage device 17 using a lock instruction, this indicates that the common area 18 is being used. "1" is set in the recognition word 16.

Next, the program of the CPU 13 makes a lock request to use the common area 18 using the lock function and reads the recognition word, but the request is not successful because the CPU II is using it. When the lock request is not accepted, this information is set in a flip-flop circuit which is a storage means called INTLK211, and the second time the CPU1
In the lock access command issued from 3, no lock request is issued, and the corresponding data is transferred onto the buffer memory 14 in the same way as normal fetching of data from the main memory 17. Thereafter, the recognition word 16 is fetched from the buffer storage 14 without issuing a lock request until the CPU I releases the lock. When CPUII releases the lock,
The content of "0" is stored in the recognition word 16 on the main memory 17 by the CPU II. At this time, the stored address is also sent to the CPU 18, and the CPU 13
IC 15 invalidates the contents of buffer storage 14 corresponding to that address. Since the corresponding content on the buffer memory 14 has been invalidated, the next time the recognition word 16 is fetched from the CPU 13, the data will be transferred from the main memory 17; Since the content of is already “0”, CP
At U13, it is determined that the lock request is successful. So C
The PU 13 issues a lock request again and locks the buffer memory 14.
By fetching the recognition word 16 from the main memory 17 without using the lock, confirming that it is "0", and setting "1" in the recognition word 16 to indicate that the lock has been obtained, other CPII Minimize access interruption from. In other words, access to the main memory 17 of the CPU I is
Access to the main memory 17 of the CPU II is interrupted only twice, the first time and the last time the lock request is issued again, so that access to the main memory 17 of the CPU II is interrupted to a minimum. Although the present embodiment has been described using the present PU configuration, the method of the present invention can be similarly applied even if the CPU configuration becomes more multiplexed.

Also, when storing in a buffer storage device, recognition word 1
6 may be considered to be a memory block that includes the recognition word 16 as usual, but even in that case, when the processing unit notifies the invalidation of the memory block, there is a high probability that the recognition word is being rewritten, and access during locking. The effect of the present invention in reducing interruptions is not compromised.

As described above, according to the present invention, interruption of access to a locked processing device can be reduced by a simple method, and the effect is significant.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the present invention. FIG. 2 is a diagram showing an operation time chart of the present invention.
Explanation of symbols, 11... CPU-1, 12... Buffer storage 1, 13... CPU-2, 14...
... Buffer memory 2, 15 ... Buffer invalidation mechanism, 16 ... Recognition word, 17 ... Main storage device, 18 ... Common area, 19 ...・・・・・・
Stored address information, 110...BIC (
buffer invalidation signal), 21... ACLOCK
(Instruction by lock access), 22...BR
(branch instruction), 24...LOCK (lock request), 25...virtual lock (not actually locked), 26...LKMSR (fetch from main memory using lock access, i.e. , access from other CPUs is prohibited during this period), 27...BS
R (data fetch from buffer storage), 28...
...MOV (data fetch from main memory), 29.
...UNS (indicates that the lock request was not successful) 210.・・・・・・Already W (timing to store data from main memory in buffer memo), 211...
. . . INTLK (sets information in the flip-flop circuit), 212 . . . Symbol indicating main memory access prohibition. Tsutomu's lacquer Z map

Claims (1)

[Claims] 1 An information processing system consisting of a plurality of processing devices each having a store-through type buffer storage device, in which a common area commonly used by the plurality of processing devices exists in the main storage device, wherein a specific processing device is When locking and using a common area on the main memory, use a lock access command to continue the recognition word in the main memory, confirm that it has not been locked by another processing device, and then lock the recognition word. In a locking method for storage device access that is used by rewriting the state, each processing device is provided with a storage means for storing the fact that the lock is being accessed, and when the lock access command is issued, the recognition word is locked by another processing device. When indicating that the recognition word or the memory block containing the recognition word is stored in the buffer storage device, the ineffectiveness of the recognition word or the memory block containing the recognition word is notified from another processing device. A locking method for accessing a storage device, characterized in that a lock access command is issued again based on the contents of the storage means.