From e3148ea20e02bcb4d0764bfb93dc841938325c7b Mon Sep 17 00:00:00 2001
From: Alejandro Alonso <alejandroalonsofernandez@gmail.com>
Date: Fri, 23 Jan 2026 13:34:19 +0100
Subject: [PATCH] :tada: Adding performance logs flag

---
 common/src/app/common/flags.cljc      |  2 +
 frontend/src/app/main/data/event.cljs | 71 ++++++++++++++-------------
 2 files changed, 39 insertions(+), 34 deletions(-)

diff --git a/common/src/app/common/flags.cljc b/common/src/app/common/flags.cljc
index 8c26778e90..b7b5e18f7c 100644
--- a/common/src/app/common/flags.cljc
+++ b/common/src/app/common/flags.cljc
@@ -134,6 +134,8 @@
     :subscriptions
     :subscriptions-old
     :inspect-styles
+    ;; Enable performance logs in devconsole (disabled by default)
+    :perf-logs
 
     ;; Security layer middleware that filters request by fetch
     ;; metadata headers
diff --git a/frontend/src/app/main/data/event.cljs b/frontend/src/app/main/data/event.cljs
index 41daafdda6..7ee1d63225 100644
--- a/frontend/src/app/main/data/event.cljs
+++ b/frontend/src/app/main/data/event.cljs
@@ -476,23 +476,24 @@
   (when (and (some? (.-PerformanceObserver js/window)) (nil? @longtask-observer*))
     (let [observer (js/PerformanceObserver.
                     (fn [list _]
-                      (doseq [entry (.getEntries list)]
-                        (let [dur (.-duration entry)
-                              start (.-startTime entry)
-                              attrib (.-attribution entry)
-                              attrib-count (when attrib (.-length attrib))
-                              first-attrib (when (and attrib-count (> attrib-count 0)) (aget attrib 0))
-                              attrib-name (when first-attrib (.-name first-attrib))
-                              attrib-ctype (when first-attrib (.-containerType first-attrib))
-                              attrib-cid (when first-attrib (.-containerId first-attrib))
-                              attrib-csrc (when first-attrib (.-containerSrc first-attrib))]
+                      (when (contains? cf/flags :perf-logs)
+                        (doseq [entry (.getEntries list)]
+                          (let [dur (.-duration entry)
+                                start (.-startTime entry)
+                                attrib (.-attribution entry)
+                                attrib-count (when attrib (.-length attrib))
+                                first-attrib (when (and attrib-count (> attrib-count 0)) (aget attrib 0))
+                                attrib-name (when first-attrib (.-name first-attrib))
+                                attrib-ctype (when first-attrib (.-containerType first-attrib))
+                                attrib-cid (when first-attrib (.-containerId first-attrib))
+                                attrib-csrc (when first-attrib (.-containerSrc first-attrib))]
 
-                          (.warn js/console (str "[perf] long task " (Math/round dur) "ms at " (Math/round start) "ms"
-                                                 (when first-attrib
-                                                   (str " attrib:name=" attrib-name
-                                                        " ctype=" attrib-ctype
-                                                        " cid=" attrib-cid
-                                                        " csrc=" attrib-csrc))))))))]
+                            (.warn js/console (str "[perf] long task " (Math/round dur) "ms at " (Math/round start) "ms"
+                                                   (when first-attrib
+                                                     (str " attrib:name=" attrib-name
+                                                          " ctype=" attrib-ctype
+                                                          " cid=" attrib-cid
+                                                          " csrc=" attrib-csrc)))))))))]
       (.observe observer #js{:entryTypes #js["longtask"]})
       (reset! longtask-observer* observer))))
 
@@ -505,28 +506,30 @@
     (let [last (atom (.now js/performance))
           id (js/setInterval
               (fn []
-                (let [now (.now js/performance)
-                      expected (+ @last interval-ms)
-                      drift (- now expected)
-                      current-op @current-op*
-                      measures (.getEntriesByType js/performance "measure")
-                      mlen (.-length measures)
-                      last-measure (when (> mlen 0) (aget measures (dec mlen)))
-                      meas-name (when last-measure (.-name last-measure))
-                      meas-detail (when last-measure (.-detail last-measure))
-                      meas-count (when meas-detail (unchecked-get meas-detail "count"))]
-                  (reset! last now)
-                  (when (> drift threshold-ms)
-                    (.warn js/console
-                           (str "[perf] event loop stall: " (Math/round drift) "ms"
-                                (when current-op (str " op=" current-op))
-                                (when meas-name (str " last=" meas-name))
-                                (when meas-count (str " count=" meas-count)))))))
+                (when (contains? cf/flags :perf-logs)
+                  (let [now (.now js/performance)
+                        expected (+ @last interval-ms)
+                        drift (- now expected)
+                        current-op @current-op*
+                        measures (.getEntriesByType js/performance "measure")
+                        mlen (.-length measures)
+                        last-measure (when (> mlen 0) (aget measures (dec mlen)))
+                        meas-name (when last-measure (.-name last-measure))
+                        meas-detail (when last-measure (.-detail last-measure))
+                        meas-count (when meas-detail (unchecked-get meas-detail "count"))]
+                    (reset! last now)
+                    (when (> drift threshold-ms)
+                      (.warn js/console
+                             (str "[perf] event loop stall: " (Math/round drift) "ms"
+                                  (when current-op (str " op=" current-op))
+                                  (when meas-name (str " last=" meas-name))
+                                  (when meas-count (str " count=" meas-count))))))))
               interval-ms)]
       (reset! stall-timer* id))))
 
 (defn init!
-  "Install perf observers in dev builds. Safe to call multiple times."
+  "Install perf observers in dev builds. Safe to call multiple times.
+  Perf logs are disabled by default. Enable them with the :perf-logs flag in config."
   []
   (when ^boolean js/goog.DEBUG
     (install-long-task-observer!)