diff --git a/kernel_perf_agent/__init__.py b/kernel_perf_agent/__init__.py
index 1f49766..47bb96e 100644
--- a/kernel_perf_agent/__init__.py
+++ b/kernel_perf_agent/__init__.py
@@ -14,5 +14,4 @@
 
 """Kernel Performance Agent package."""
 
-# "Kernel Performance Agent package
 __all__ = []
diff --git a/kernel_perf_agent/kernel_opt/profiler/__init__.py b/kernel_perf_agent/kernel_opt/profiler/__init__.py
index d177194..d0a028c 100644
--- a/kernel_perf_agent/kernel_opt/profiler/__init__.py
+++ b/kernel_perf_agent/kernel_opt/profiler/__init__.py
@@ -12,7 +12,6 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-"""kernel_perf_agent package."""
+"""NCU profiling module for kernel performance analysis."""
 
-# Kernel Perf Agent package
 __all__ = []
diff --git a/kernel_perf_agent/kernel_opt/profiler/ncu_profiler.py b/kernel_perf_agent/kernel_opt/profiler/ncu_profiler.py
index 4b1bf83..cac9907 100644
--- a/kernel_perf_agent/kernel_opt/profiler/ncu_profiler.py
+++ b/kernel_perf_agent/kernel_opt/profiler/ncu_profiler.py
@@ -67,6 +67,9 @@
         "smsp__warp_issue_stalled_barrier_per_warp_active.pct",
         "smsp__warp_issue_stalled_branch_resolving_per_warp_active.pct",
         "smsp__sass_average_branch_targets_threads_uniform.pct",
+        # new metrics for SOL
+        "sm__throughput.avg.pct_of_peak_sustained_elapsed",
+        "gpu__compute_memory_throughput.avg.pct_of_peak_sustained_elapsed",
     ]
 )
 
diff --git a/kernel_perf_agent/kernel_opt/roofline/__init__.py b/kernel_perf_agent/kernel_opt/roofline/__init__.py
new file mode 100644
index 0000000..f3d8afe
--- /dev/null
+++ b/kernel_perf_agent/kernel_opt/roofline/__init__.py
@@ -0,0 +1,17 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Roofline analysis module for kernel performance optimization."""
+
+__all__ = []
diff --git a/kernel_perf_agent/kernel_opt/roofline/ncu_roofline.py b/kernel_perf_agent/kernel_opt/roofline/ncu_roofline.py
new file mode 100644
index 0000000..c7d6c39
--- /dev/null
+++ b/kernel_perf_agent/kernel_opt/roofline/ncu_roofline.py
@@ -0,0 +1,255 @@
+# Copyright (c) Meta Platforms, Inc. and affiliates.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""
+Roofline Analysis Module using NCU SOL (Speed of Light) Metrics.
+
+This module uses NCU's built-in SOL metrics to determine kernel efficiency
+relative to hardware limits
+
+NCU SOL metrics directly measure how close performance is to peak:
+- Compute SOL: SM throughput as % of peak
+- Memory SOL: DRAM throughput as % of peak
+
+Updated in January 2026
+"""
+
+import logging
+from dataclasses import asdict, dataclass, field
+from typing import Any
+
+
+# NCU metrics needed for roofline analysis
+# Note: The profiler (ncu_profiler.py) collects these and more metrics.
+# This list documents the minimum required for roofline decisions.
+
+NCU_ROOFLINE_METRICS = [
+    # Primary SOL metrics (Speed of Light)
+    "gpu__compute_memory_throughput.avg.pct_of_peak_sustained_elapsed",  # Memory SOL
+    "sm__throughput.avg.pct_of_peak_sustained_elapsed",  # Compute SOL
+    # Tensor core detection
+    "sm__pipe_tensor_cycles_active.avg.pct_of_peak_sustained_active",
+]
+
+
+@dataclass
+class RooflineConfig:
+    """Configuration for roofline analysis."""
+
+    threshold_pct: float = 95.0  # SOL % to consider at roofline
+    early_stop: bool = True  # Stop optimization when at roofline
+    convergence_rounds: int = 5  # Rounds without improvement to trigger stop
+    min_improvement_pct: float = 0.1  # Minimum improvement to continue
+    tensor_core_threshold: float = 5.0  # Min TC activity % to consider TC usage
+    underutilized_threshold: float = 60.0  # Both SOL < this % = underutilized
+
+
+@dataclass
+class RooflineResult:
+    """Result of roofline analysis using NCU SOL metrics."""
+
+    # SOL metrics from NCU (primary)
+    compute_sol_pct: float  # SM throughput as % of peak
+    memory_sol_pct: float  # DRAM throughput as % of peak
+
+    # Derived efficiency (max of compute/memory SOL)
+    efficiency_pct: float  # Primary efficiency metric for decisions
+    at_roofline: bool  # True if efficiency >= threshold_pct
+    headroom_pct: float  # 100 - efficiency
+
+    # Classification
+    bottleneck: str  # "memory" | "compute" | "underutilized"
+    uses_tensor_cores: bool  # Whether TC is active
+
+    # Data quality
+    warnings: list[str] = field(default_factory=list)
+
+    def to_dict(self) -> dict[str, Any]:
+        """Convert to dictionary for serialization."""
+        return asdict(self)
+
+
+class RooflineAnalyzer:
+    """Analyzes kernel performance using NCU SOL metrics."""
+
+    def __init__(
+        self,
+        config: RooflineConfig | None = None,
+        logger: logging.Logger | None = None,
+    ):
+        """
+        Initialize the roofline analyzer.
+
+        Args:
+            config: Roofline configuration (defaults to RooflineConfig())
+            logger: Logger instance
+        """
+        self.config = config or RooflineConfig()
+        self.logger = logger or logging.getLogger(__name__)
+        self._efficiency_history: list[float] = []
+
+    def _is_using_tensor_cores(self, ncu_metrics: dict[str, Any]) -> bool:
+        """Detect tensor core usage from NCU metrics."""
+        tc_cycles = ncu_metrics.get(
+            "sm__pipe_tensor_cycles_active.avg.pct_of_peak_sustained_active", 0
+        )
+        return tc_cycles > self.config.tensor_core_threshold
+
+    def _classify_bottleneck(self, compute_sol: float, memory_sol: float) -> str:
+        """
+        Classify bottleneck based on SOL metrics.
+
+        The LOWER SOL value indicates the bottleneck.
+        If both are lower than threshold, the kernel is underutilized (could be occupancy,
+        instruction mix, launch config, dependency stalls, etc.).
+        """
+        threshold = self.config.underutilized_threshold
+
+        # Both low = underutilized (neither resource is saturated)
+        if memory_sol < threshold and compute_sol < threshold:
+            return "underutilized"
+
+        # Return whichever is lower
+        if memory_sol <= compute_sol:
+            return "memory"
+        else:
+            return "compute"
+
+    def analyze(
+        self,
+        ncu_metrics: dict[str, Any],
+    ) -> RooflineResult:
+        """
+        Analyze kernel performance using NCU SOL metrics.
+
+        Args:
+            ncu_metrics: NCU profiling metrics dictionary
+
+        Returns:
+            RooflineResult with SOL-based efficiency analysis
+        """
+        warnings: list[str] = []
+
+        # Extract SOL metrics with missing-key detection
+        compute_key = "sm__throughput.avg.pct_of_peak_sustained_elapsed"
+        memory_key = "gpu__compute_memory_throughput.avg.pct_of_peak_sustained_elapsed"
+
+        compute_missing = compute_key not in ncu_metrics
+        memory_missing = memory_key not in ncu_metrics
+
+        if compute_missing:
+            self.logger.warning("Compute SOL metric missing from NCU data")
+            warnings.append("Compute SOL metric missing")
+        if memory_missing:
+            self.logger.warning("Memory SOL metric missing from NCU data")
+            warnings.append("Memory SOL metric missing")
+
+        # Fail only if both keys are absent
+        if compute_missing and memory_missing:
+            return RooflineResult(
+                compute_sol_pct=0,
+                memory_sol_pct=0,
+                efficiency_pct=0,
+                at_roofline=False,
+                headroom_pct=100,
+                bottleneck="unknown",
+                uses_tensor_cores=False,
+                warnings=["Analysis failed - no SOL metrics in NCU data"],
+            )
+
+        compute_sol = ncu_metrics.get(compute_key, 0)
+        memory_sol = ncu_metrics.get(memory_key, 0)
+
+        # Primary efficiency: use max of compute/memory
+        efficiency = max(compute_sol, memory_sol)
+
+        # Tensor core detection
+        uses_tc = self._is_using_tensor_cores(ncu_metrics)
+
+        # Classify bottleneck
+        bottleneck = self._classify_bottleneck(compute_sol, memory_sol)
+
+        # Check if at roofline
+        at_roofline = efficiency >= self.config.threshold_pct
+
+        return RooflineResult(
+            compute_sol_pct=compute_sol,
+            memory_sol_pct=memory_sol,
+            efficiency_pct=efficiency,
+            at_roofline=at_roofline,
+            headroom_pct=max(0, 100 - efficiency),
+            bottleneck=bottleneck,
+            uses_tensor_cores=uses_tc,
+            warnings=warnings,
+        )
+
+    def should_stop(self, result: RooflineResult) -> tuple[bool, str]:
+        """
+        Check if optimization should stop based on SOL efficiency and convergence.
+
+        Args:
+            result: RooflineResult from analyze()
+
+        Returns:
+            Tuple of (should_stop, reason)
+        """
+        self._efficiency_history.append(result.efficiency_pct)
+
+        # Condition 1: At roofline threshold (if early_stop enabled)
+        if self.config.early_stop and result.at_roofline:
+            return (
+                True,
+                f"At roofline ({result.efficiency_pct:.1f}% SOL >= "
+                f"{self.config.threshold_pct}%)",
+            )
+
+        # Condition 2: Efficiency converged (no improvement for N rounds)
+        if len(self._efficiency_history) >= self.config.convergence_rounds:
+            recent = self._efficiency_history[-self.config.convergence_rounds :]
+            improvement = max(recent) - min(recent)
+            if improvement < self.config.min_improvement_pct:
+                return (
+                    True,
+                    f"Converged (improvement {improvement:.2f}% < "
+                    f"{self.config.min_improvement_pct}%)",
+                )
+
+        return False, ""
+
+    def reset_history(self) -> None:
+        """Reset efficiency history for a new optimization run."""
+        self._efficiency_history = []
+
+
+def format_roofline_summary(result: RooflineResult) -> str:
+    """Format a human-readable summary of roofline analysis."""
+    lines = [
+        "=== Roofline Analysis ===",
+        f"SOL Efficiency: {result.efficiency_pct:.1f}%",
+        f"  Compute SOL: {result.compute_sol_pct:.1f}%",
+        f"  Memory SOL:  {result.memory_sol_pct:.1f}%",
+        f"  Bottleneck:  {result.bottleneck}",
+        f"  Tensor Cores: {'Yes' if result.uses_tensor_cores else 'No'}",
+        "",
+    ]
+
+    if result.at_roofline:
+        lines.append("Status: AT ROOFLINE")
+    else:
+        lines.append(f"Headroom: {result.headroom_pct:.1f}%")
+
+    if result.warnings:
+        lines.append(f"Warnings: {'; '.join(result.warnings)}")
+
+    return "\n".join(lines)