Add cache hit rate to cache debugging

1 files changed, 14 insertions, 0 deletions

diff --git a/src/engine/SCons/CacheDir.py b/src/engine/SCons/CacheDir.py
index 0a378c2..704b9a5 100644
--- a/src/engine/SCons/CacheDir.py
+++ b/src/engine/SCons/CacheDir.py
@@ -47,10 +47,12 @@ def CacheRetrieveFunc(target, source, env):
     t = target[0]
     fs = t.fs
     cd = env.get_CacheDir()
+    cd.requests += 1
     cachedir, cachefile = cd.cachepath(t)
     if not fs.exists(cachefile):
         cd.CacheDebug('CacheRetrieve(%s):  %s not in cache\n', t, cachefile)
         return 1
+    cd.hits += 1
     cd.CacheDebug('CacheRetrieve(%s):  retrieving from %s\n', t, cachefile)
     if SCons.Action.execute_actions:
         if fs.islink(cachefile):
@@ -148,6 +150,8 @@ class CacheDir(object):
         one exists,  if not the config file is created and
         the default config is written, as well as saved in the object.
         """
+        self.requests = 0
+        self.hits = 0
         self.path = path
         self.current_cache_debug = None
         self.debugFP = None
@@ -269,6 +273,16 @@ class CacheDir(object):
             self.current_cache_debug = cache_debug
         if self.debugFP:
             self.debugFP.write(fmt % (target, os.path.split(cachefile)[1]))
+            self.debugFP.write("requests: %d, hits: %d, misses: %d, hit rate: %.2f%%\n" %
+                               (self.requests, self.hits, self.misses, self.hit_ratio))
+
+    @property
+    def hit_ratio(self):
+        return (100.0 * self.hits / self.requests if self.requests > 0 else 100)
+
+    @property
+    def misses(self):
+        return self.requests - self.hits
 
     def is_enabled(self):
         return cache_enabled and self.path is not None