diff --git a/build/build-clang/Remove-FlushViewOfFile-when-unmaping-gcda-files-clang-15.patch b/build/build-clang/Remove-FlushViewOfFile-when-unmaping-gcda-files-clang-15.patch
new file mode 100644
index 000000000000..4b0edbe4714f
--- /dev/null
+++ b/build/build-clang/Remove-FlushViewOfFile-when-unmaping-gcda-files-clang-15.patch
@@ -0,0 +1,30 @@
+From 78a6bcfed4b73f13b9973afd69b76067dd4a5dde Mon Sep 17 00:00:00 2001
+From: Calixte Denizet <calixte.denizet@gmail.com>
+Date: Mon, 4 Oct 2021 11:07:56 +0200
+Subject: [PATCH] Remove FlushViewOfFile when unmaping gcda files   - it can
+ causes bad performances with slow disks;   - MS docs say that it's mainly
+ useful in case of hard failures (OS crash, electrical failure, ...): so it's
+ useless to call this function when ccov builds run on CI.
+
+---
+ compiler-rt/lib/profile/GCDAProfiling.c | 5 -----
+ 1 file changed, 5 deletions(-)
+
+diff --git a/compiler-rt/lib/profile/GCDAProfiling.c b/compiler-rt/lib/profile/GCDAProfiling.c
+index 4293e8f7b5bf..83650d33c95d 100644
+--- a/compiler-rt/lib/profile/GCDAProfiling.c
++++ b/compiler-rt/lib/profile/GCDAProfiling.c
+@@ -286,11 +286,6 @@ static int map_file() {
+
+ static void unmap_file(void) {
+ #if defined(_WIN32)
+-  if (!FlushViewOfFile(write_buffer, file_size)) {
+-    fprintf(stderr, "profiling: %s: cannot flush mapped view: %lu\n", filename,
+-            GetLastError());
+-  }
+-
+   if (!UnmapViewOfFile(write_buffer)) {
+     fprintf(stderr, "profiling: %s: cannot unmap mapped view: %lu\n", filename,
+             GetLastError());
+--
+2.33.0
diff --git a/build/build-clang/clang-trunk.json b/build/build-clang/clang-trunk.json
index b05667dfff7b..b435d2244a68 100644
--- a/build/build-clang/clang-trunk.json
+++ b/build/build-clang/clang-trunk.json
@@ -6,7 +6,7 @@
     "unpoison-thread-stacks_clang_10.patch",
     "downgrade-mangling-error_clang_12.patch",
     "bug47258-extract-symbols-mbcs.patch",
-    "Remove-FlushViewOfFile-when-unmaping-gcda-files.patch",
+    "build/build-clang/Remove-FlushViewOfFile-when-unmaping-gcda-files-clang-15.patch",
     "fuzzing_ccov_build_clang_12.patch"
   ]
 }