diff --git a/snappy-test.cc b/snappy-test.cc
index 223cd92..6a0611e 100644
--- a/snappy-test.cc
+++ b/snappy-test.cc
@@ -204,27 +204,32 @@
       benchmark_runs[run].cpu_time_us = benchmark_cpu_time_us;
     }
 
+    string heading = StringPrintf("%s/%d", name_.c_str(), test_case_num);
+    string human_readable_speed;
+
     nth_element(benchmark_runs,
                 benchmark_runs + kMedianPos,
                 benchmark_runs + kNumRuns,
                 BenchmarkCompareCPUTime());
     int64 real_time_us = benchmark_runs[kMedianPos].real_time_us;
     int64 cpu_time_us = benchmark_runs[kMedianPos].cpu_time_us;
-    int64 bytes_per_second = benchmark_bytes_processed * 1000000 / cpu_time_us;
-
-    string heading = StringPrintf("%s/%d", name_.c_str(), test_case_num);
-    string human_readable_speed;
-    if (bytes_per_second < 1024) {
-      human_readable_speed = StringPrintf("%dB/s", bytes_per_second);
-    } else if (bytes_per_second < 1024 * 1024) {
-      human_readable_speed = StringPrintf(
-          "%.1fkB/s", bytes_per_second / 1024.0f);
-    } else if (bytes_per_second < 1024 * 1024 * 1024) {
-      human_readable_speed = StringPrintf(
-          "%.1fMB/s", bytes_per_second / (1024.0f * 1024.0f));
+    if (cpu_time_us <= 0) {
+      human_readable_speed = "?";
     } else {
-      human_readable_speed = StringPrintf(
-          "%.1fGB/s", bytes_per_second / (1024.0f * 1024.0f * 1024.0f));
+      int64 bytes_per_second =
+          benchmark_bytes_processed * 1000000 / cpu_time_us;
+      if (bytes_per_second < 1024) {
+        human_readable_speed = StringPrintf("%dB/s", bytes_per_second);
+      } else if (bytes_per_second < 1024 * 1024) {
+        human_readable_speed = StringPrintf(
+            "%.1fkB/s", bytes_per_second / 1024.0f);
+      } else if (bytes_per_second < 1024 * 1024 * 1024) {
+        human_readable_speed = StringPrintf(
+            "%.1fMB/s", bytes_per_second / (1024.0f * 1024.0f));
+      } else {
+        human_readable_speed = StringPrintf(
+            "%.1fGB/s", bytes_per_second / (1024.0f * 1024.0f * 1024.0f));
+      }
     }
 
     fprintf(stderr,