From: Jaya Prakash <jayaprakash@ibm.com>
Date: Wed, 1 Jul 2026 13:22:48 +0000 (+0000)
Subject: os/bluestore: add fast-path allocation latency perf counter for Allocator
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=b883573faabca54109a2ddf6556f4be49ebbfc6f;p=ceph.git

os/bluestore: add fast-path allocation latency perf counter for Allocator

Fixes: https://tracker.ceph.com/issues/76936

Signed-off-by: Jaya Prakash <jayaprakash@ibm.com>
---

diff --git a/src/os/bluestore/AllocatorBase.cc b/src/os/bluestore/AllocatorBase.cc
index a7c068dcfeb..3f0a78bfceb 100644
--- a/src/os/bluestore/AllocatorBase.cc
+++ b/src/os/bluestore/AllocatorBase.cc
@@ -215,7 +215,7 @@ void AllocatorPerf::_init_logger(std::string_view name) {
 
   b.add_time_avg(l_bluestore_allocator_alloc_process_lat,
     "alloc_process_lat",
-    "Allocator processing latency",
+    "Allocator processing latency while holding lock",
     "apl",
     PerfCountersBuilder::PRIO_USEFUL);
   b.add_time_avg(l_bluestore_allocator_lock_wait_lat,
@@ -223,6 +223,11 @@ void AllocatorPerf::_init_logger(std::string_view name) {
     "Allocator lock wait latency",
     "lwl",
     PerfCountersBuilder::PRIO_USEFUL);
+  b.add_time_avg(l_bluestore_allocator_nolock_process_lat,
+    "nolock_process_lat",
+    "Allocator lockless fast-path allocation latency",
+    "fpl",
+    PerfCountersBuilder::PRIO_USEFUL);
 
   logger = b.create_perf_counters();
 
diff --git a/src/os/bluestore/AllocatorBase.h b/src/os/bluestore/AllocatorBase.h
index dc567c3c2c9..3db35466007 100644
--- a/src/os/bluestore/AllocatorBase.h
+++ b/src/os/bluestore/AllocatorBase.h
@@ -26,6 +26,7 @@ enum {
   l_bluestore_allocator_first = 732300,
   l_bluestore_allocator_alloc_process_lat,
   l_bluestore_allocator_lock_wait_lat,
+  l_bluestore_allocator_nolock_process_lat,
   l_bluestore_allocator_last
 };
 
diff --git a/src/os/bluestore/Btree2Allocator.cc b/src/os/bluestore/Btree2Allocator.cc
index 7531f059852..d01839d3518 100644
--- a/src/os/bluestore/Btree2Allocator.cc
+++ b/src/os/bluestore/Btree2Allocator.cc
@@ -86,9 +86,13 @@ int64_t Btree2Allocator::allocate(
     max_alloc_size = p2align(uint64_t(cap), (uint64_t)block_size);
   }
   uint64_t cached_chunk_offs = 0;
+  auto fast_alloc_start = mono_clock::now();
   if (cache && cache->try_get(&cached_chunk_offs, want)) {
     num_free -= want;
     extents->emplace_back(cached_chunk_offs, want);
+    logger->tinc_with_max(
+        l_bluestore_allocator_nolock_process_lat,
+        mono_clock::now() - fast_alloc_start);
     return want;
   }
   auto lock_wait_start = mono_clock::now();