resource_mgmt: add option to filter out results collected before a gi…

…ven timepoint
ballard26 · Nov 7, 2023 · e83cae6 · e83cae6
1 parent 8e377a9
commit e83cae6
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Showing 2 changed files with 21 additions and 8 deletions.
diff --git a/src/v/resource_mgmt/cpu_profiler.cc b/src/v/resource_mgmt/cpu_profiler.cc
@@ -51,8 +51,9 @@ ss::future<> cpu_profiler::stop() {
     ss::engine().set_cpu_profiler_enabled(false);
 }
 
-ss::future<std::vector<cpu_profiler::shard_samples>>
-cpu_profiler::results(std::optional<ss::shard_id> shard_id) {
+ss::future<std::vector<cpu_profiler::shard_samples>> cpu_profiler::results(
+  std::optional<ss::shard_id> shard_id,
+  std::optional<ss::lowres_clock::time_point> filter_before) {
     if (_gate.is_closed()) {
         co_return std::vector<shard_samples>{};
     }
@@ -84,10 +85,15 @@ cpu_profiler::results(std::optional<ss::shard_id> shard_id) {
     co_return results;
 }
 
-cpu_profiler::shard_samples cpu_profiler::shard_results() const {
+cpu_profiler::shard_samples cpu_profiler::shard_results(
+  std::optional<ss::lowres_clock::time_point> filter_before) const {
     size_t dropped_samples = 0;
     absl::node_hash_map<ss::simple_backtrace, size_t> backtraces;
     for (auto& results_buffer : _results_buffers) {
+        if (filter_before && results_buffer.polled_time < *filter_before) {
+            continue;
+        }
+
         dropped_samples += results_buffer.dropped_samples;
         for (auto& result : results_buffer.samples) {
             backtraces[result.user_backtrace]++;
@@ -120,7 +126,8 @@ void cpu_profiler::poll_samples() {
     resourceslog.trace(
       "Polled {} samples from the CPU profiler", results_buffer.size());
 
-    _results_buffers.emplace_front(dropped_samples, std::move(results_buffer));
+    _results_buffers.emplace_front(
+      dropped_samples, std::move(results_buffer), ss::lowres_clock::now());
 }
 
 bool cpu_profiler::is_enabled() const {
@@ -178,6 +185,8 @@ cpu_profiler::override_and_get_results(
     // enable the profiler if disabled pre-override.
     on_enabled_change();
 
+    auto polling_start_time = ss::lowres_clock::now();
+
     try {
         co_await ss::sleep_abortable(timeout, _as);
     } catch (const ss::sleep_aborted&) {
@@ -188,7 +197,7 @@ cpu_profiler::override_and_get_results(
     // check if profiler should be disabled post-override.
     on_enabled_change();
 
-    co_return co_await results(shard_id);
+    co_return co_await results(shard_id, polling_start_time);
 }
 
 } // namespace resources
diff --git a/src/v/resource_mgmt/cpu_profiler.h b/src/v/resource_mgmt/cpu_profiler.h
@@ -70,12 +70,15 @@ class cpu_profiler : public ss::peering_sharded_service<cpu_profiler> {
 
     // Collects `shard_results()` for each shard in a node and returns
     // them as a vector.
-    ss::future<std::vector<shard_samples>>
-    results(std::optional<ss::shard_id> shard_id);
+    ss::future<std::vector<shard_samples>> results(
+      std::optional<ss::shard_id> shard_id,
+      std::optional<ss::lowres_clock::time_point> filter_before = std::nullopt);
 
     // Returns the samples and dropped samples from the shard this function
     // is called on.
-    shard_samples shard_results() const;
+    shard_samples shard_results(
+      std::optional<ss::lowres_clock::time_point> filter_before
+      = std::nullopt) const;
 
     // Enables the profiler for `timeout` milliseconds, then returns samples
     // collected during that time period.
@@ -99,6 +102,7 @@ class cpu_profiler : public ss::peering_sharded_service<cpu_profiler> {
     struct profiler_result {
         size_t dropped_samples;
         std::vector<seastar::cpu_profiler_trace> samples;
+        ss::lowres_clock::time_point polled_time;
     };
 
     // Buffers to copy sampled traces from seastar into so