diff --git a/pytential/linalg/hmatrix.py b/pytential/linalg/hmatrix.py
index ee9f47fc5..cd32ad379 100644
--- a/pytential/linalg/hmatrix.py
+++ b/pytential/linalg/hmatrix.py
@@ -42,6 +42,9 @@
     class LinearOperator:
         pass
 
+import logging
+logger = logging.getLogger(__name__)
+
 
 __doc__ = """
 Hierarical Matrix Construction
@@ -518,6 +521,10 @@ def P2PClusterMatrixBuilderWithDiagonal(*args, **kwargs):
         tree_kind=_tree_kind,
         max_particles_in_box=_max_particles_in_box)
 
+    logger.info("tree levels: %d", ctree.nlevels)
+    logger.info("cluster count: %d", cluster_index.nclusters)
+    logger.info("root cluster sizes: %s", list(np.diff(cluster_index.starts)))
+
     from pytential.linalg.utils import TargetAndSourceClusterList
     tgt_src_index = TargetAndSourceClusterList(
         targets=cluster_index, sources=cluster_index)