fix typo and refine

test=develop

paddle/fluid/framework/ir/seqpool_concat_fuse_pass.cc

@@ -50,7 +50,7 @@ PDNode* BuildSeqPoolConcatPattern(PDPattern* pattern,
       // the other one should be unused empty var.
       if (is_nth_input_var_of_concat(x->outputs[0], idx)) {
         satisfied_all = satisfied_all && x->outputs[1]->IsVar() &&
-                        x->outputs[1]->outputs.size() == 0;
+                        x->outputs[1]->outputs.empty();
       } else {
         satisfied_all =
             satisfied_all && is_nth_input_var_of_concat(x->outputs[1], idx) &&

paddle/fluid/operators/jit/benchmark.cc

@@ -52,11 +52,11 @@ struct BenchFunc {
     for (int i = 0; i < FLAGS_burning; ++i) {
       tgt(args...);
     }
-    auto start = paddle::platform::PosixInNsec() / 1e-3;
+    auto start = paddle::platform::PosixInNsec() * 1e-3;
     for (int i = 0; i < FLAGS_repeat; ++i) {
       tgt(args...);
     }
-    auto end = paddle::platform::PosixInNsec() / 1e-3;
+    auto end = paddle::platform::PosixInNsec() * 1e-3;
     return static_cast<double>(end - start) / FLAGS_repeat;
   }
 };