diff --git a/tensorflow/compiler/xla/service/memory_space_assignment.cc b/tensorflow/compiler/xla/service/memory_space_assignment.cc
index 10c3d60f202..a0650650f88 100644
--- a/tensorflow/compiler/xla/service/memory_space_assignment.cc
+++ b/tensorflow/compiler/xla/service/memory_space_assignment.cc
@@ -254,12 +254,6 @@ float MemorySpaceAssignmentCostAnalysis::GetInstructionElapsedDueToCompute(
           cost_analysis_.per_second_rate(HloCostAnalysis::kTranscendentalsKey));
 }
 
-float MemorySpaceAssignmentCostAnalysis::
-    GetInstructionElapsedDueToMemorySlowdown(int64 bytes) const {
-  return bytes /
-         cost_analysis_.per_second_rate(HloCostAnalysis::kBytesAccessedKey);
-}
-
 float MemorySpaceAssignmentCostAnalysis::GetInstructionElapsedDueToMemory(
     const HloInstruction& instruction,
     absl::optional<int64> operand_in_alternate_mem,
diff --git a/tensorflow/compiler/xla/service/memory_space_assignment.h b/tensorflow/compiler/xla/service/memory_space_assignment.h
index 7bffcc25523..f6104d6ba98 100644
--- a/tensorflow/compiler/xla/service/memory_space_assignment.h
+++ b/tensorflow/compiler/xla/service/memory_space_assignment.h
@@ -123,12 +123,6 @@ class MemorySpaceAssignmentCostAnalysis {
       absl::optional<int64> operand_in_alternate_mem = absl::nullopt,
       bool output_in_alternate_mem = false) const;
 
-  // Returns the elapsed time in seconds that other BufferIntervals are slowed
-  // down, due to the prefetching of current bytes. Assuming other
-  // BufferIntervals needs default memory bandwidth, and only current
-  // BufferInterval is prefetched.
-  float GetInstructionElapsedDueToMemorySlowdown(int64 bytes) const;
-
   // Returns the estimated elapsed duration of the instruction in seconds.  It
   // assumes all operands and outputs of the instruction are in the default
   // memory.