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bpo-29585: optimize site.py startup time by methane · Pull Request #136 · python/cpython

Hum, did I miss something? sysconfig is still imported by the site module on macOS by getsitepackages():

        if sys.platform == "darwin":
            # for framework builds *only* we add the standard Apple
            # locations.
            from sysconfig import get_config_var
            framework = get_config_var("PYTHONFRAMEWORK")
            if framework:
                sitepackages.append(
                        os.path.join("/Library", framework,
                            '%d.%d' % sys.version_info[:2], "site-packages"))

macbook:master haypo$ ./python.exe -c 'import sys; print("sysconfig" in sys.modules)'
True

I suggest this additionnal change:

diff --git a/Lib/site.py b/Lib/site.py
index 500c59b..929252d 100644
--- a/Lib/site.py
+++ b/Lib/site.py
@@ -334,15 +334,12 @@ def getsitepackages(prefixes=None):
         else:
             sitepackages.append(prefix)
             sitepackages.append(os.path.join(prefix, "lib", "site-packages"))
-        if sys.platform == "darwin":
-            # for framework builds *only* we add the standard Apple
-            # locations.
-            from sysconfig import get_config_var
-            framework = get_config_var("PYTHONFRAMEWORK")
-            if framework:
-                sitepackages.append(
-                        os.path.join("/Library", framework,
-                            '%d.%d' % sys.version_info[:2], "site-packages"))
+        # for framework builds *only* we add the standard Apple
+        # locations.
+        if sys.platform == "darwin" and sys._framework:
+            sitepackages.append(
+                    os.path.join("/Library", sys._framework,
+                        '%d.%d' % sys.version_info[:2], "site-packages"))
     return sitepackages
 
 def addsitepackages(known_paths, prefixes=None):

With this additionnal change, the speedup on macOS is quite significant: -13.4 ms (1.61x faster)!

macbook:master haypo$ ./python.exe -m perf command --inherit=PYTHONPATH -v -o ref.json -- ./python.exe -c pass 
...
macbook:master haypo$ ./python.exe -m perf command --inherit=PYTHONPATH -v -o pr136.json -- ./python.exe -c pass
...
macbook:master haypo$ ./python.exe -m perf compare_to ref.json pr136.json 
Mean +- std dev: [ref] 35.4 ms +- 1.7 ms -> [pr136] 22.0 ms +- 1.9 ms: 1.61x faster (-38%)

cc @1st1: Yury, since you use macOS, you probably want to see this change merged :-)