From b587042215dc3ff7312674eff681617a45c514b5 Mon Sep 17 00:00:00 2001
From: Marcus Holland-Moritz <github@mhxnet.de>
Date: Thu, 22 May 2025 13:54:17 +0200
Subject: [PATCH] chore(segmenter): add debug logging with memory usage
 information

---
 src/writer/segmenter.cpp | 36 +++++++++++++++++++++++++++++++-----
 1 file changed, 31 insertions(+), 5 deletions(-)

diff --git a/src/writer/segmenter.cpp b/src/writer/segmenter.cpp
index 1cc6523a..a3215e47 100644
--- a/src/writer/segmenter.cpp
+++ b/src/writer/segmenter.cpp
@@ -149,16 +149,28 @@ class fast_multimap {
     return false;
   }
 
-  void clear() {
-    values_.clear();
-    collisions_.clear();
-  }
-
   DWARFS_FORCE_INLINE blockhash_t const& values() const { return values_; };
   DWARFS_FORCE_INLINE collision_t const& collisions() const {
     return collisions_;
   };
 
+  size_t memory_usage() const {
+    auto phmap_mem = []<typename T>(T const& m) {
+      return m.capacity() * sizeof(typename T::slot_type) + m.capacity() + 1;
+    };
+
+    auto mem = phmap_mem(values_) + phmap_mem(collisions_);
+
+    for (auto const& c : collisions_) {
+      if (c.second.size() > MaxCollInline) {
+        mem +=
+            c.second.capacity() * sizeof(typename collision_vector::value_type);
+      }
+    }
+
+    return mem;
+  }
+
  private:
   blockhash_t values_;
   collision_t collisions_;
@@ -245,6 +257,8 @@ class alignas(64) bloom_filter {
     std::transform(cbegin(), cend(), other.cbegin(), begin(), std::bit_or<>{});
   }
 
+  size_t memory_usage() const { return size_ / 8; }
+
  private:
   DWARFS_FORCE_INLINE bits_type const* cbegin() const { return bits_; }
   DWARFS_FORCE_INLINE bits_type const* cend() const {
@@ -592,6 +606,18 @@ class active_block : private GranularityPolicy {
     data_.reserve(this->frames_to_bytes(capacity_in_frames_));
   }
 
+  ~active_block() {
+    LOG_DEBUG << "block " << num_ << " destroyed, "
+              << size_with_unit(offsets_.memory_usage()) << " offset memory ("
+              << fmt::format("{:.1f}",
+                             static_cast<double>(offsets_.memory_usage()) /
+                                 offsets_.values().size())
+              << " bytes per offset, " << offsets_.values().size()
+              << " offsets, " << offsets_.collisions().size()
+              << " collisions), " << size_with_unit(filter_.memory_usage())
+              << " bloom filter";
+  }
+
   DWARFS_FORCE_INLINE size_t num() const { return num_; }
 
   DWARFS_FORCE_INLINE size_t size_in_frames() const {