Communication-inter-cores.md

 ## Liens sur les interruptions
+
+
+- [Simple Multicore Core to Core Communication Using FreeRTOS Message
+Buffers -
+FreeRTOS](https://www.freertos.org/2020/02/simple-multicore-core-to-core-communication-using-freertos-message-buffers.html
+)
+
+- [How do interrupts work on multicore ARM cpu - Stack
+Overflow](https://stackoverflow.com/questions/11811276/how-do-interrupts-work-on-multicore-arm-cpu
+)
+
+- [ARM CoreLink GIC-500 Generic Interrupt Controller Technical Reference
+Manual
+r1p1](https://developer.arm.com/documentation/ddi0516/e/functional-description/operation/interrupt-types
+)
+
+## Une introduction fournie par ChatGPT
+
+```
+In ARM architectures, such as ARMv8-A, which is commonly used in modern
+smartphones, tablets, and other devices, communication between cores
+typically occurs through shared memory and synchronization mechanisms.
+These architectures often consist of multiple cores (usually two or
+more) that can work together to perform parallel processing tasks.
+Here's a high-level overview of how communication between cores in ARM
+architecture can be achieved:
+
+1. Shared Memory:
+ARM cores can access a shared region of memory. This shared memory can
+be used to exchange data and communicate between different cores. It is
+essential to ensure that data consistency is maintained during
+communication, especially when multiple cores can read and write to the
+shared memory concurrently.
+
+2. Synchronization Mechanisms:
+To avoid data races and ensure proper coordination between cores,
+synchronization mechanisms are used. Common synchronization primitives
+in ARM architectures include:
+
+   - Spin Locks: Spin locks are used to protect critical sections of
+code that can be executed by only one core at a time. If a core
+attempts to acquire a spin lock that is already held by another core,
+it will repeatedly check (spin) until the lock is released.
+   
+   - Semaphores: Semaphores are used to control access to shared
+resources. A semaphore is a variable that keeps track of the number of
+available resources. When a core wants to access a resource, it checks
+the semaphore, and if the resource is available, the core decrements
+the semaphore count and proceeds. Otherwise, it waits until the
+resource becomes available.
+
+   - Barrier: Barriers are used to ensure that all cores have reached a
+certain point in the code before proceeding further. This is helpful
+when you want to synchronize the execution of specific tasks across
+multiple cores.
+
+   - Mutexes: Mutexes (short for "mutual exclusion") are similar to
+spin locks but are typically more efficient in cases where waiting for
+the lock is expected to be a relatively long-duration event.
+
+3. Inter-Processor Interrupts (IPIs):
+Inter-processor interrupts are used to signal events or trigger actions
+on other cores. One core can send an interrupt signal to another core,
+and the receiving core can handle the interrupt by executing a specific
+interrupt handler.
+
+It's important to note that the exact communication methods and
+synchronization primitives available might vary depending on the
+specific ARM architecture and the operating system running on the
+device.
+
+When developing parallel code for ARM architectures, it's crucial to
+ensure proper synchronization and avoid data hazards and race
+conditions to achieve correct and efficient multi-core processing. It's
+often helpful to use high-level synchronization libraries or APIs
+provided by the operating system to handle core communication and
+synchronization tasks effectively.
+```
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