From: Xuehan Xu <xxhdx1985126@gmail.com>
Date: Mon, 20 Feb 2023 08:44:29 +0000 (+0000)
Subject: crimson/os/seastore: count transactions pending on seastore's throttler
X-Git-Tag: v18.1.0~305^2
X-Git-Url: http://git-server-git.apps.pok.os.sepia.ceph.com/?a=commitdiff_plain;h=refs%2Fpull%2F50176%2Fhead;p=ceph.git

crimson/os/seastore: count transactions pending on seastore's throttler

Signed-off-by: Xuehan Xu <xxhdx1985126@gmail.com>
---

diff --git a/src/crimson/common/throttle.cc b/src/crimson/common/throttle.cc
index 8aeaa1fdd7d9..88d1859f32f5 100644
--- a/src/crimson/common/throttle.cc
+++ b/src/crimson/common/throttle.cc
@@ -1,3 +1,6 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:nil -*-
+// vim: ts=8 sw=2 smarttab
+
 #include "throttle.h"
 
 namespace crimson::common {
@@ -29,9 +32,11 @@ seastar::future<> Throttle::get(size_t c)
   if (max == 0u) {
     return seastar::make_ready_future<>();
   }
+  pending++;
   return on_free_slots.wait([this, c] {
     return !_should_wait(c);
   }).then([this, c] {
+    pending--;
     count += c;
     return seastar::make_ready_future<>();
   });
diff --git a/src/crimson/common/throttle.h b/src/crimson/common/throttle.h
index fea471c8d61f..2998cb5f8431 100644
--- a/src/crimson/common/throttle.h
+++ b/src/crimson/common/throttle.h
@@ -15,6 +15,7 @@ namespace crimson::common {
 class Throttle final : public ThrottleInterface {
   size_t max = 0;
   size_t count = 0;
+  size_t pending = 0;
   // we cannot change the "count" of seastar::semaphore after it is created,
   // so use condition_variable instead.
   seastar::condition_variable on_free_slots;
@@ -31,6 +32,9 @@ public:
   size_t get_max() const {
     return max;
   }
+  size_t get_pending() const {
+    return pending;
+  }
   void reset_max(size_t m);
 private:
   bool _should_wait(size_t c) const;
diff --git a/src/crimson/os/seastore/seastore.cc b/src/crimson/os/seastore/seastore.cc
index 6680f52a80a6..04522f1e7ad7 100644
--- a/src/crimson/os/seastore/seastore.cc
+++ b/src/crimson/os/seastore/seastore.cc
@@ -173,6 +173,14 @@ void SeaStore::register_metrics()
 	  return throttler.get_current();
 	},
 	sm::description("transactions that are running inside seastore")
+      ),
+      sm::make_gauge(
+	"pending_transactions",
+	[this] {
+	  return throttler.get_pending();
+	},
+	sm::description("transactions waiting to get "
+		        "through seastore's throttler")
       )
     }
   );