saving rewrites [run_process_replay] (tinygrad#6501)

* save rewrites with TRACK_MATCH_STATS=2 [run_process_replay]

* cleaner

tinygrad/ops.py

@@ -720,6 +720,7 @@ def rewrite(self, uop:UOp) -> Optional[UOp]:
 # *** tracking pattern matcher ***
 
 TRACK_MATCH_STATS = getenv("TRACK_MATCH_STATS", 0)
+contexts: List[Tuple[UOp, List[Tuple[UOp, UOp]]]] = []
 match_stats:Dict[UPat, List[Union[int, float]]] = dict()
 class TrackedPattenMatcher(PatternMatcher):
   def __init__(self, patterns:List[Tuple[UPat, Callable]]):
@@ -740,23 +741,27 @@ def rewrite(self, uop:UOp) -> Optional[UOp]:
         match_stats[p][0] += 1
         match_stats[p][2] += (et:=time.perf_counter()-st)
         match_stats[p][3] += et
-        if TRACK_MATCH_STATS >= 2: print(f"{et*1e6:7.2f} us -- ", p.printable())
+        if TRACK_MATCH_STATS >= 3: print(f"{et*1e6:7.2f} us -- ", p.printable())
+        if TRACK_MATCH_STATS >= 2: contexts[-1][1].append((uop, ret))
         return ret # NOTE: if it returns None, we keep trying to match
       match_stats[p][2] += time.perf_counter()-st
     return None
 
 if TRACK_MATCH_STATS:
   PatternMatcher = TrackedPattenMatcher  # type: ignore
-  import atexit
+  import atexit, pickle
   @atexit.register
   def print_match_stats():
     ret = [0,0,0.0,0.0]
     for k,v in sorted(list(match_stats.items()), key=lambda x: x[1][2]):
       loc_str = f"{k.location[0].split('/')[-1]}:{k.location[1]}"
-      if getenv("UPAT_FILE", loc_str) not in loc_str: continue
-      print(f"{v[0]:6d} / {v[1]:7d} -- {v[3]*1000.:9.2f} / {v[2]*1000.:9.2f} ms -- {loc_str:15s}", k.printable())
+      if v[1] != 0: print(f"{v[0]:6d} / {v[1]:7d} -- {v[3]*1000.:9.2f} / {v[2]*1000.:9.2f} ms -- {loc_str:15s}", k.printable())
       ret = [x+y for x,y in zip(ret, v)]
     print(f"{ret[0]:6d} / {ret[1]:7d} -- {ret[3]*1000.:9.2f} / {ret[2]*1000.:9.2f} ms -- TOTAL")
+    if TRACK_MATCH_STATS >= 2:
+      with open("/tmp/rewrites.pkl", "wb") as f:
+        print(f"rewrote {len(contexts)} graphs and applied {sum(len(x[1]) for x in contexts)} rules, saved to /tmp/rewrites.pkl")
+        pickle.dump(contexts, f)
 
 # *** simple graph rewrite engine ***
 
@@ -773,4 +778,6 @@ def rewrite(self, n:UOp) -> UOp:
       x = UOp(*replace_source) if new_src != n.src else n
       self.nodes[replace_source] = self.replace[n] = found = self.rewrite(new_x) if (new_x := self.pm.rewrite(x)) else x
     return found
-def graph_rewrite(sink:UOp, pm:PatternMatcher) -> UOp: return RewriteContext(pm).rewrite(sink)
+def graph_rewrite(sink:UOp, pm:PatternMatcher) -> UOp:
+  if TRACK_MATCH_STATS >= 2: contexts.append((sink, []))
+  return RewriteContext(pm).rewrite(sink)