50 performance optimizations

[EdmondDantes]

No description provided.

[Copilot]

Pull Request Overview

This PR implements "50 performance optimizations" for the async PHP extension, focusing on fiber context management and coroutine switching performance improvements. The changes introduce a fiber context pooling system to reduce allocation overhead, optimize circular buffer operations with inline functions for hot paths, and restructure the scheduler for better performance.

Key changes include:

• Fiber context pooling: Implementation of a reusable fiber context pool with ASYNC_FIBER_POOL_SIZE configuration
• Circular buffer optimizations: Inline specialized versions for pointer operations with bitwise arithmetic
• Scheduler restructuring: Major refactoring of context switching logic and fiber management

Reviewed Changes

Copilot reviewed 17 out of 17 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
scope.c	Replace zend_async_waker_destroy calls with zend_async_waker_clean for optimized cleanup
scheduler.h	Add fiber context pool configuration and new fiber context creation API
scheduler.c	Major refactoring with fiber context pooling, optimized switching logic, and reorganized code structure
run-tests.sh	Add -m flag to test runner for memory leak checking
php_async.h	Add fiber_context_pool to global state
libuv_reactor.c	Optimize reactor execution by skipping uv_run() when no handles are active
internal/circular_buffer.h	Add inline optimized functions for pointer operations with specialized push/pop
internal/circular_buffer.c	Move circular_buffer_is_not_empty to inline implementation
docs/context-switching-flow.puml	Add PlantUML documentation for fiber workflow
coroutine.h	Restructure with new async_fiber_context_t and embedded waker design
coroutine.c	Complete rewrite with embedded wakers, fiber context management, and reorganized structure
benchmarks/*.php	Add comprehensive benchmarking suite for performance testing
async_API.c	Add missing zend_async_waker_clean calls after suspend operations
async.c	Replace zend_async_waker_destroy with zend_async_waker_clean

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[Copilot]

The bitwise AND operation assumes buffer capacity is always a power of 2, but there's no validation to ensure this constraint. If capacity is not a power of 2, the modulo operation will be incorrect and could cause buffer corruption.

[Copilot]

Same issue as above - bitwise AND operation for modulo only works correctly when capacity is a power of 2. This could lead to incorrect tail advancement if capacity is not a power of 2.

Suggested change

	buffer->tail = (buffer->tail + 1) & (buffer->capacity - 1);
	buffer->tail = (buffer->tail + 1) % buffer->capacity;

[Copilot]

ASYNC_FIBER_POOL_SIZE is defined as 4, which is a power of 2, but the circular buffer inline optimizations in circular_buffer.h assume all capacities are powers of 2. If this size is ever changed to a non-power-of-2 value, the bitwise operations will fail.

[Copilot]

[nitpick] The comparison false == circular_buffer_is_full(buffer) uses Yoda condition style inconsistently with the rest of the codebase. Consider using !circular_buffer_is_full(buffer) for better readability and consistency.

Suggested change

	if (buffer->capacity > 0 && false == circular_buffer_is_full(buffer)) {
	if (buffer->capacity > 0 && !circular_buffer_is_full(buffer)) {

[Copilot]

The assertion checks waker status but the embedded waker is initialized in the constructor. If a coroutine is destroyed before being properly dequeued, this assertion will fail. The assertion should handle the case where the waker was never queued.

Suggested change

	ZEND_ASSERT(ZEND_ASYNC_WAKER_NOT_IN_QUEUE(&coroutine->waker) &&
	"Coroutine waker must be dequeued before destruction");
	ZEND_ASSERT((ZEND_ASYNC_WAKER_NOT_IN_QUEUE(&coroutine->waker) || !coroutine->waker.was_ever_queued) &&
	"Coroutine waker must be dequeued before destruction or never queued");