Avoid negative values in eval metrics (#1533)

optimum/habana/transformers/trainer.py

@@ -1766,6 +1766,14 @@ def evaluate(
         num_samples = output.num_samples - self.args.throughput_warmup_steps * total_batch_size
         num_steps = math.ceil(output.num_samples / total_batch_size) - self.args.throughput_warmup_steps
 
+        eval_steps = math.ceil(output.num_samples / total_batch_size)
+        if eval_steps <= self.args.throughput_warmup_steps:
+            logger.warning(
+                f" Warmup steps are taken into account for the throughput calculation because the number of evaluation steps ({eval_steps}) is smaller than the number of warmup steps ({self.args.throughput_warmup_steps})"
+            )
+            num_samples = output.num_samples
+            num_steps = eval_steps
+
         output.metrics.update(
             speed_metrics(
                 metric_key_prefix,