diff --git a/.bazelrc b/.bazelrc
index 3eb4b1c36462..5b02ced73e1a 100644
--- a/.bazelrc
+++ b/.bazelrc
@@ -27,8 +27,12 @@ build:windows --remote_download_all
 # consider moving more flags out to separate files.
 import %workspace%/build/ci.bazelrc
 
-# Enable webgpu
-build --//src/workerd/io:enable_experimental_webgpu=True
+# Enable webgpu. Merely fetching the required Dawn library and computing the repo mapping based on
+# it slows down the Windows build significantly, so only enable this on Unix and for Windows release
+# builds. This is mostly motivated by compile time constraints, we hope to lift this limitation
+# again if this Windows performance bottleneck gets fixed within Bazel.
+build:unix --//src/workerd/io:enable_experimental_webgpu=True
+build:release_windows --//src/workerd/io:enable_experimental_webgpu=True
 
 # Avoid generating duplicate runfile trees. This will become the default in a future bazel version.
 build --nolegacy_external_runfiles
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index fdfb596693b5..5edf4a935a00 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -207,6 +207,14 @@ jobs:
           else
             echo "Disk cache does not exist: ~/bazel-disk-cache"
           fi
+      - name: Upload build statistics
+        if: always()
+        uses: actions/upload-artifact@v4
+        with:
+          name: ${{ matrix.os.name }}${{ matrix.config.suffix }}-bazel-profile
+          path: |
+            build.bazel-profile
+            test.bazel-profile
       - name: Bazel shutdown
         # Check that there are no .bazelrc issues that prevent shutdown.
         run: bazel shutdown
diff --git a/build/BUILD.wpt b/build/BUILD.wpt
index 757b227041c7..99e2f95515b1 100644
--- a/build/BUILD.wpt
+++ b/build/BUILD.wpt
@@ -2,16 +2,7 @@
 # Licensed under the Apache 2.0 license found in the LICENSE file or at:
 #     https://opensource.org/licenses/Apache-2.0
 
-directories = glob(
-    ["*"],
-    exclude = glob(
-        ["*"],
-        exclude_directories = 1,
-    ) + [
-        ".*",
-    ],
-    exclude_directories = 0,
-)
+directories = ["url"]
 
 [filegroup(
     name = dir,
diff --git a/build/ci.bazelrc b/build/ci.bazelrc
index 939875a9715a..4cd17c029df4 100644
--- a/build/ci.bazelrc
+++ b/build/ci.bazelrc
@@ -18,3 +18,7 @@ build:ci --show_progress_rate_limit=1
 build:ci --color=yes
 # Indicate support for more terminal columns, 100 is the line length recommended by KJ style.
 build:ci --terminal_columns=100
+
+# Emit build profile so that slow builds can be investigated
+build:ci --profile build.bazel-profile
+test:ci --profile test.bazel-profile
diff --git a/src/wpt/BUILD.bazel b/src/wpt/BUILD.bazel
index 4eda7837a58b..f8ad536a57f8 100644
--- a/src/wpt/BUILD.bazel
+++ b/src/wpt/BUILD.bazel
@@ -1,8 +1,7 @@
 filegroup(
     name = "wpt-test-harness",
     srcs = glob(
-        include = ["**/*"],
-        allow_empty = True,
+        include = ["*.js"],
     ),
     visibility = ["//visibility:public"],
 )