Synchronization method, multi-core processor system, and synchronization system
A synchronization method is executed by a multi-core processor system. The synchronization method includes registering based on a synchronous command issued from a first CPU, CPUs to be synchronized and a count of the CPUs into a specific table; counting by each of the CPUs and based on a synchronous signal from the first CPU, an arrival count for a synchronous point, and creating by each of the CPUs, a second shared memory area that is a duplication of a first shared memory area accessed by processes executed by the CPUs; and comparing the first shared memory area and the second shared memory area when the arrival count becomes equal to the count of the CPUs, and based on a result of the comparison, judging the processes executed by the CPUs.
1. A synchronization method executed by a multi-processor system, the synchronization method comprising:
sending, by a first CPU among a plurality of CPUs, a synchronous signal that is issued based on a synchronous command included in a synchronization processing to the plurality of CPUs excluding the first CPU, the plurality of CPUs accessing a first shared memory area to execute the synchronization processing;
increasing, by a second CPU among the plurality of CPUs and different from the first CPU and based on receiving the synchronous signal from the first CPU, an arrival count for a synchronous point by one, the synchronous point indicating a position of the synchronous command in the synchronization processing and the arrival count indicating a number of CPUs arriving at the synchronous point among the plurality of CPUs;
sending, by the second CPU, a ready signal indicating an arrival to the synchronous point, to the plurality of CPUs excluding the first CPU and the second CPU as a result of increasing the arrival count by one;
creating, by the second CPU, a second shared memory area and a third shared memory area that are a duplication of the first shared memory area and accessing, by the second CPU, data stored only in the second shared memory area to execute a subsequent processing subsequent to the synchronization processing when the arrival count is not equal to count of the CPUs excluding the first CPU as a result of increasing the arrival count by one;
when the arrival count is equal to the count of the CPUs excluding the first CPU as a result of receiving the ready signal from a CPU different from the second CPU and the first CPU:
first comparing, by the second CPU, the second shared memory area and the third shared memory area,
when a first comparing result indicates a coincidence, second comparing, by the second CPU, the first shared memory area and the second shared memory area,
when a second comparing result indicates a coincidence, the CPUs excluding the first CPU are synchronized and the synchronization processing is complete,
when the first comparing result or the second comparing result indicates a non-coincidence, interrupting and re-executing the subsequent processing.
2. A multi-processor system comprising:
a first CPU, among a plurality of CPUs, that is configured to send a synchronous signal that is issued based on a synchronous command included in a synchronization processing to the plurality of CPUs excluding the first CPU, the plurality of CPUs accessing a first shared memory area to execute the synchronization processing; and
a second CPU among the plurality of CPUs that is different from the first CPU and is configured to:
increase, based on receiving the synchronous signal from the first CPU, an arrival count for a synchronous point by one, the synchronous point indicating a position of the synchronous command in the synchronization processing and the arrival count indicating a number of CPUs arriving at the synchronous point among the plurality of CPUs;
send a ready signal indicating an arrival to the synchronous point to the plurality of CPUs excluding the first CPU and the second CPU as a result of increasing the arrival count by one;
create a second shared memory area and a third shared memory area by duplicating the first shared memory area and access data stored only in the second shared memory area to execute a subsequent processing subsequent to the synchronization processing when the arrival count is not equal to count of the CPUs excluding the first CPU as a result of increasing the arrival count by one;
when the arrival count is equal to the count of the CPUs excluding the first CPU as a result of receiving the ready signal from a CPU different from the second CPU and the first CPU:
first compare, by the second CPU, the second shared memory area and the third shared memory area,
when a first comparing result indicates a coincidence, second comparing, by the second CPU, the first shared memory area and the second shared memory area,
when a second comparing result indicates a coincidence, the CPUs excluding the first CPU are synchronized and the synchronization processing is complete,
when the first comparing result or the second comparing result indicates a non-coincidence, interrupting and re-executing the subsequent processing.
3. The multi-processor system according to claim 2 , wherein the second CPU is further configured to
deactivate reception of the synchronous signal when the first comparing result or the second comparing result indicates the non-coincidence.
4. A synchronization system comprising:
a plurality of CPUs including at least a first CPU, the first CPU accessing a first shared memory area to execute synchronization processing, the first CPU being configured to send a synchronous signal that is issued based on a synchronous command included in a synchronization processing to the plurality of CPUs excluding the first CPU; and
a second CPU among the plurality of CPUs and different from the first CPU configured to:
increase, based on receiving the synchronous signal from the first CPU, an arrival count for a synchronous point by one, the synchronous point indicating a position of the synchronous command in the synchronization processing and the arrival count indicating a number of CPUs arriving at the synchronous point among the plurality of CPUs,
send a ready signal indicating an arrival to the synchronous point to the plurality of CPUs excluding the first CPU and the second CPU as a result of increasing the arrival count by one,
create a second shared memory area and a third shared memory area by duplicating the first shared memory area and access data stored only in the second shared memory area to execute a subsequent processing subsequent to the synchronization processing when the arrival count is not equal to count of the CPUs excluding the first CPU as a result of increasing the arrival count by one,
when the arrival count is equal to the count of the CPUs excluding the first CPU as a result of receiving the ready signal from a CPU different from the second CPU and the first CPU:
first compare, by the second CPU, the second shared memory area and the third shared memory area,
when a first comparing result indicates a coincidence, second compare, by the second CPU, the first shared memory area and the second shared memory area,
when a second comparing result indicates a coincidence, the CPUs excluding the first CPU are synchronized and the synchronization processing is complete,
when the first comparing result or the second comparing result indicates a non-coincidence, interrupt and re-execute the subsequent processing.