Usermode busy waiting for performance gains #56
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Replaces blocking WaitForSingleObject calls with busy-wait polling in SendReadRequest and SendWriteRequest. Reads use a sentinel value on the destination buffer to detect completion as soon as MmCopyVirtualMemory overwrites it, before the kernel even signals KmEvent. Writes spin-poll the event with zero timeout to avoid thread scheduler wake-up latency.
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Currently, I am still debating whether or not I want #38 implemented or not, since it obviously spikes CPU core usage due to the busy-waiting. I am not sure whether this trade off is worth it for roprw. perhaps we could consider some toggle setting for usage/when compiling the project? |
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Summary
WaitForSingleObject(INFINITE)with busy-wait polling inSendReadRequestandSendWriteRequest0xC0FEBABEC0FEBABE) written to the destination buffer, detecting completion as soon asMmCopyVirtualMemoryoverwrites it before the kernel even signalsKmEventCloses #38
Test plan