[llvm-exegesis][NFC] Add more comments.

llvm-svn: 334811

llvm/tools/llvm-exegesis/lib/BenchmarkResult.h

@@ -51,7 +51,10 @@ struct InstructionBenchmark {
   ModeE Mode;
   std::string CpuName;
   std::string LLVMTriple;
+  // The number of instructions inside the repeated snippet. For example, if a
+  // snippet of 3 instructions is repeated 4 times, this is 12.
   int NumRepetitions = 0;
+  // Note that measurements are per instruction.
   std::vector<BenchmarkMeasure> Measurements;
   std::string Error;
   std::string Info;