[PHP web] Lower initial memory allocation for PHP instances#3192
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[PHP web] Lower initial memory allocation for PHP instances#3192
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adamziel
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[Type] Enhancement
adamziel
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Summary
Reduces the initial memory allocation from 1024MB to 256MB per PHP instance. The PHP runtime still has room to grow when needed through Emscripten's memory growth mechanism, but starts with a much smaller footprint. Testing shows this reduces peak memory usage by approximately 40% and idle memory consumption by 3x. In Safari Technology Preview, peak usage dropped from over 2GB to around 1.26GB.
Rationale
WordPress Playground has been allocating 1GB of memory upfront for each PHP instance. When the Playground boots multiple instances to handle concurrent operations during startup, this creates memory spikes exceeding 3GB. On memory-constrained devices like older iPhones or budget Android phones, these spikes can cause crashes or severe performance degradation.
The lower memory floor makes WordPress Playground more accessible across a wider range of devices while maintaining full functionality. PHP instances can still allocate additional memory as WordPress runs more complex operations, but typical workflows can now stay within the reduced limits.
Test plan