From bd5aa7223d7dc21ca4f5a219bd5ba50aa8b0ac8a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Micha=C5=82=20Chojnowski?= <michal.chojnowski@scylladb.com>
Date: Wed, 18 Dec 2024 14:23:37 +0100
Subject: [PATCH] checkpoint

---
 include/seastar/core/reactor.hh |  3 +++
 include/seastar/util/tracer.hh  | 11 +++++++----
 src/core/fair_queue.cc          |  2 +-
 src/core/io_queue.cc            |  2 +-
 src/core/metrics.cc             |  1 +
 src/core/reactor.cc             | 10 ++++++++++
 6 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/include/seastar/core/reactor.hh b/include/seastar/core/reactor.hh
index 9296ced12b2..a223e5080f7 100644
--- a/include/seastar/core/reactor.hh
+++ b/include/seastar/core/reactor.hh
@@ -68,6 +68,7 @@
 #include <cstring>
 #include <memory>
 #include <string_view>
+#include <map>
 #include <unordered_map>
 #include <vector>
 #include <unistd.h>
@@ -281,6 +282,8 @@ private:
     };
 
     boost::container::static_vector<std::unique_ptr<task_queue>, max_scheduling_groups()> _task_queues;
+public:
+    std::vector<std::tuple<int, std::reference_wrapper<const sstring>, float>> list_groups();
     internal::scheduling_group_specific_thread_local_data _scheduling_group_specific_data;
     int64_t _last_vruntime = 0;
     task_queue_list _active_task_queues;
diff --git a/include/seastar/util/tracer.hh b/include/seastar/util/tracer.hh
index 3fba591ff08..c46b410f2ee 100644
--- a/include/seastar/util/tracer.hh
+++ b/include/seastar/util/tracer.hh
@@ -15,7 +15,7 @@ struct tracer {
     size_t _cur_pos = 0;
 
     tracer() {
-        for (int i = 0; i < 80; ++i) {
+        for (int i = 0; i < 480; ++i) {
             _old.push_back(std::vector<std::byte>());
         }
         _current.resize(buffer_size);
@@ -72,6 +72,7 @@ enum class trace_events {
     IO_QUEUE,
     IO_DISPATCH,
     IO_COMPLETE,
+    MONITORING_SCRAPE,
     COUNT,
 };
 
@@ -164,14 +165,16 @@ inline void tracepoint_replenish(uint64_t new_head) {
 }
 
 inline void tracepoint_dispatch_queue(uint8_t id) {
-    auto p = reinterpret_cast<char*>(g_tracer.write(5));
-    p = seastar::write_le<uint32_t>(p, static_cast<uint32_t>(trace_events::DISPATCH_QUEUE));
-    p = seastar::write_le<uint8_t>(p, id);
+    tracepoint_unary<uint8_t>(trace_events::DISPATCH_QUEUE, id);
 }
 
 inline void tracepoint_dispatch_requests() {
     tracepoint_nullary(trace_events::DISPATCH_REQUESTS);
 }
 
+inline void tracepoint_monitoring_scrape() {
+    tracepoint_nullary(trace_events::MONITORING_SCRAPE);
+}
+
 
 } // namespace seastar
diff --git a/src/core/fair_queue.cc b/src/core/fair_queue.cc
index 309b722e900..2be38e6c32a 100644
--- a/src/core/fair_queue.cc
+++ b/src/core/fair_queue.cc
@@ -340,7 +340,7 @@ void fair_queue::dispatch_requests(std::function<void(fair_queue_entry&)> cb) {
     capacity_t dispatched = 0;
     boost::container::small_vector<priority_class_ptr, 2> preempt;
 
-    tracepoint_dispatch_requests();
+    // tracepoint_dispatch_requests();
     while (!_handles.empty() && (dispatched < _group.per_tick_grab_threshold())) {
         priority_class_data& h = *_handles.top();
         tracepoint_dispatch_queue(h._id);
diff --git a/src/core/io_queue.cc b/src/core/io_queue.cc
index 7bdb44b2bb4..dad0cfd02d2 100644
--- a/src/core/io_queue.cc
+++ b/src/core/io_queue.cc
@@ -236,7 +236,7 @@ class io_desc_read_write final : public io_completion {
         io_log.trace("dev {} : req {} queue  len {} capacity {}", _ioq.dev_id(), fmt::ptr(this), _dnl.length(), _fq_capacity);
         static thread_local uint64_t io_id = 0;
         _io_id = io_id++;
-        tracepoint_io_queue(_fq_capacity, dnl.rw_idx(), _io_id);
+        tracepoint_io_queue(dnl.rw_idx(), _fq_capacity, _io_id);
     }
 
     virtual void set_exception(std::exception_ptr eptr) noexcept override {
diff --git a/src/core/metrics.cc b/src/core/metrics.cc
index 14f1d5a53eb..5e68eb0aeb9 100644
--- a/src/core/metrics.cc
+++ b/src/core/metrics.cc
@@ -375,6 +375,7 @@ const value_map& get_value_map() {
 }
 
 foreign_ptr<values_reference> get_values() {
+    tracepoint_monitoring_scrape();
     shared_ptr<values_copy> res_ref = ::seastar::make_shared<values_copy>();
     auto& res = *(res_ref.get());
     auto& mv = res.values;
diff --git a/src/core/reactor.cc b/src/core/reactor.cc
index 8f8063c2211..cd10eae7292 100644
--- a/src/core/reactor.cc
+++ b/src/core/reactor.cc
@@ -246,6 +246,16 @@ shard_id reactor::cpu_id() const {
     return _id;
 }
 
+std::vector<std::tuple<int, std::reference_wrapper<const sstring>, float>> reactor::list_groups() {
+    std::vector<std::tuple<int, std::reference_wrapper<const sstring>, float>> result;
+    for (int i = 0; i < _task_queues.size(); ++i) {
+        if (_task_queues[i]) {
+            result.emplace_back(i, _task_queues[i]->_name, _task_queues[i]->_shares);
+        }
+    }
+    return result;
+}
+
 void reactor::update_shares_for_queues(internal::priority_class pc, uint32_t shares) {
     for (auto&& q : _io_queues) {
         q.second->update_shares_for_class(pc, shares);