Optimize sbp equality (#4435)

Co-authored-by: Noneflow-ci-bot <69100618+oneflow-ci-bot@users.noreply.github.com>

oneflow/core/job/sbp_parallel.cpp

@@ -18,7 +18,17 @@ limitations under the License.
 
 namespace oneflow {
 
-bool operator==(const SbpParallel& lhs, const SbpParallel& rhs) { return PbMd().Equals(lhs, rhs); }
+bool operator==(const SbpParallel& lhs, const SbpParallel& rhs) {
+  if (lhs.parallel_type_case() == rhs.parallel_type_case()) {
+    if (lhs.has_split_parallel()) {
+      return lhs.split_parallel().axis() == rhs.split_parallel().axis();
+    } else {
+      return true;
+    }
+  } else {
+    return false;
+  }
+}
 
 bool operator!=(const SbpParallel& lhs, const SbpParallel& rhs) { return !(lhs == rhs); }
 
@@ -46,7 +56,11 @@ SbpParallel GetDualSbpParallel(const SbpParallel& sbp_parallel) {
 }
 
 bool operator==(const ParallelDistribution& lhs, const ParallelDistribution& rhs) {
-  return PbMd().Equals(lhs, rhs);
+  if (lhs.sbp_parallel().size() != rhs.sbp_parallel().size()) { return false; }
+  for (int i = 0; i < lhs.sbp_parallel().size(); ++i) {
+    if (lhs.sbp_parallel().Get(i) != rhs.sbp_parallel().Get(i)) { return false; }
+  }
+  return true;
 }
 
 bool operator!=(const ParallelDistribution& lhs, const ParallelDistribution& rhs) {