Understanding the Problem
In multi-core debugging with IAR C-SPY, synchronization issues often stem from cores not being properly aligned during execution. This misalignment can cause one core to run ahead or lag behind others, leading to unpredictable results in interdependent processes. Identifying the exact cause requires a systematic approach to ensure all aspects of the debugging environment are considered.
Configuration and Environment Checks
Ensure that each core’s clock settings are correctly configured in the project options. Mismatched clock speeds can cause cores to desynchronize.
Verify the linker script and memory mappings to ensure that there are no overlaps or incorrect configurations causing interference between cores.
Double-check that each core is using the latest build of the application to prevent discrepancies due to outdated code.
Use Breakpoints for Synchronization
Strategically place breakpoints in both cores at points where synchronization is crucial. This allows you to step through the code and ensure both cores are executing the expected instructions.
Use conditional breakpoints to freeze execution when specific conditions are met, such as reaching a certain memory address or variable state.
Example:
// Place a conditional breakpoint here to activate only when sharedVar matches a condition.
if (sharedVar == expectedValue) {
__breakpoint(0);
}
Inter-Core Communication
Use semaphores or mutexes for inter-core communication. This ensures that only one core accesses a shared resource at a time.
Inspect the interrupt configuration to ensure no interrupt service routines (ISRs) are causing contention between cores.
Example:
// Basic semaphore implementation for inter-core communication
void acquire_semaphore() {
while (__atomic_test_and_set(&semaphore, __ATOMIC_ACQUIRE));
}
void release_semaphore() {
__atomic_clear(&semaphore, __ATOMIC_RELEASE);
}
Analyze Debugging Output
Review the debug console logs for inconsistencies or errors. Pay attention to any warnings about data races, resource contention, or memory access violations.
Ensure that the IAR C-SPY debug trace is enabled and properly configured to monitor core execution timelines.
Utilize Core-Specific Configuration
Configure core-specific options. IAR C-SPY allows fine-tuning individual core settings, such as enabling or disabling interrupts or configuring specific startup code for each core.
Use the core selector in the C-SPY debugger to view and control specific cores individually, allowing you to isolate issues related to a particular core.
Embedded System-Specific Solutions
If your application runs on an embedded system with hardware-specific synchronization features, ensure that they are properly utilized. This could be hardware semaphores, spinning locks, or other mechanisms supported by your CPU architecture.
Check if your device manufacturer provides special libraries or APIs for multi-core synchronization and integrate them into your debugging strategy.
Conclusion
Debugging synchronization issues in multi-core systems using IAR C-SPY demands a combination of strategic breakpoints, take careful consideration of inter-core communications, and rigorous configuration checks. By ensuring that each core execution path and resource management strategy is correctly set up, developers can systematically eliminate issues and achieve stable multi-core operation.
