Feature/diff replay reset

docs/usage/cli.md

@@ -196,9 +196,10 @@ When omitted, all values default to those recorded during execution.
 
 ### Execution Options
 
-| Option                | Description                                                           |
-| --------------------- | --------------------------------------------------------------------- |
+| Option         | Description                                                           |
+| -------------- | --------------------------------------------------------------------- |
 | `--iterations`, `-it` | Number of iterations to execute the kernel for statistical evaluation |
+| `--reset-mode` | Memory reset mode between iterations: `bytes` or `diff` |
 
 
 ### Examples

docs/usage/replay.md

@@ -21,3 +21,27 @@ optimization pipelines or launch configurations.
 For a detailed explanation of the annotation API, metadata fields,
 threshold semantics, and a complete example, see
 **[Usage → Verification](verification.md)**.
+
+## Reset mode
+
+Replay restores the recorded prologue before each measured kernel run.
+When the recording has a diff epilogue, Mneme can avoid copying the
+entire prologue by restoring only the prologue byte ranges that differ
+in the epilogue:
+
+```bash
+mneme replay ... --reset-mode diff "default<O3>"
+```
+
+Supported modes are:
+
+| Mode | Behavior |
+| ---- | -------- |
+| `bytes` | Always use the original full prologue reset. |
+| `diff` | Require diff reset and fail if the epilogue is not a valid diff snapshot. Diff reset restores ranges with one device scatter kernel per warm reset. |
+
+When no reset mode is supplied, Mneme selects `diff` for diff epilogue
+snapshots and `bytes` otherwise. Diff reset uses raw ranges by default;
+tune optional coalescing with
+`MNEME_REPLAY_DIFF_SCATTER_MAX_GAP_BYTES` and chunk size with
+`MNEME_REPLAY_DIFF_SCATTER_TASK_BYTES`.

include/mneme/MnemeDeviceKernels.hpp

@@ -0,0 +1,21 @@
+#pragma once
+
+#include <cstddef>
+#include <cstdint>
+
+#include "mneme/DeviceTraits.hpp"
+
+namespace mneme {
+
+struct DiffResetScatterTask {
+  uint8_t *Dst = nullptr;
+  const uint8_t *Src = nullptr;
+  size_t Size = 0;
+};
+
+template <DeviceVendors VendorTypes>
+typename DeviceTraits<VendorTypes>::DeviceError_t launchDiffResetScatterKernel(
+    const DiffResetScatterTask *Tasks, size_t NumTasks,
+    typename DeviceTraits<VendorTypes>::DeviceStream_t Stream);
+
+} // namespace mneme