[pypy-commit] pypy stm-thread-2: Tweak tweak

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: stm-thread-2
Changeset: r61438:cadf477fe482
Date: 2013-02-19 08:35 +0100
http://bitbucket.org/pypy/pypy/changeset/cadf477fe482/

Log:	Tweak tweak

diff --git a/rpython/translator/stm/src_stm/lists.c b/rpython/translator/stm/src_stm/lists.c
--- a/rpython/translator/stm/src_stm/lists.c
+++ b/rpython/translator/stm/src_stm/lists.c
@@ -261,24 +261,20 @@
    of collisions, old items are discarded.  The eviction logic is a bit
    too simple for now. */
 
-#define FX_ENTRIES    8192
-#define FX_ASSOC      1
-#define FX_SIZE       (FX_ENTRIES * FX_ASSOC * sizeof(revision_t))
+#define FX_ENTRIES   8192
 
 struct FXCache {
   char *cache_start;
-#if FX_ASSOC > 1
   revision_t nextadd;
-#endif
   revision_t shift;
-  revision_t cache[FX_ENTRIES * FX_ASSOC * 2];
+  revision_t cache[FX_ENTRIES * 2 * 2];
 };
 
 static void fxcache_clear(struct FXCache *fxcache)
 {
-  fxcache->shift += FX_ASSOC;
-  if (fxcache->shift > (FX_ENTRIES - 1) * FX_ASSOC) {
-    memset(fxcache->cache, 0, 2 * FX_SIZE);
+  fxcache->shift += 2;
+  if (fxcache->shift > FX_ENTRIES - 2) {
+    memset(fxcache->cache, 0, sizeof(fxcache->cache));
     fxcache->shift = 0;
   }
   fxcache->cache_start = (char *)(fxcache->cache + fxcache->shift);
@@ -291,37 +287,27 @@
      */
   revision_t uitem = (revision_t)item;
   revision_t *entry = (revision_t *)
-    (fxcache->cache_start + (uitem & (FX_SIZE-sizeof(revision_t))));
+    (fxcache->cache_start + (uitem & ((FX_ENTRIES-1) * sizeof(revision_t))));
+  revision_t current, *entry2;
 
-  if (entry[0] == uitem
-#if FX_ASSOC >= 2
-      || entry[1] == uitem
-#if FX_ASSOC >= 4
-      || entry[2] == uitem || entry[3] == uitem
-#if FX_ASSOC >= 8
-      || entry[4] == uitem || entry[5] == uitem
-      || entry[6] == uitem || entry[7] == uitem
-#if FX_ASSOC >= 16
-      || entry[8] == uitem || entry[9] == uitem
-      || entry[10]== uitem || entry[11]== uitem
-      || entry[12]== uitem || entry[13]== uitem
-      || entry[14]== uitem || entry[15]== uitem
-#if FX_ASSOC >= 32
-#error "FX_ASSOC is too large"
-#endif /* 32 */
-#endif /* 16 */
-#endif /* 8 */
-#endif /* 4 */
-#endif /* 2 */
-      )
+  current = entry[0];
+  if (current == uitem)
     return 1;
 
-#if FX_ASSOC > 1
-  entry[fxcache->nextadd] = uitem;
-  fxcache->nextadd = (fxcache->nextadd + 1) & (FX_ASSOC-1);
-#else
-  entry[0] = uitem;
-#endif
+  entry2 = entry + FX_ENTRIES;
+  if (entry2[0] == uitem) {
+    entry2[0] = current;
+    entry[0] = uitem;
+    return 1;
+  }
+  if (entry2[1] == uitem) {
+    entry2[1] = current;
+    entry[0] = uitem;
+    return 1;
+  }
+
+  entry2[fxcache->nextadd] = uitem;
+  fxcache->nextadd = (fxcache->nextadd + 1) & 1;
   return 0;
 }