Prevent unnecessary loading of engines

For engines that can be reused, the unloading at the end of a pairing
is in some cases wasteful, as the same engine will be used in the next
pairing as well. In simple gauntlets the gauntlet engine will always
stay first engine, while in multi-gauntlets the oppent engine will stay
the same for an entire round. In these cases unloading is now suppressed.

diff --git a/backend.c b/backend.c
index c54a29b..e669f50 100644 (file)
--- a/backend.c
+++ b/backend.c
@@ -1397,9 +1397,13 @@ ReserveGame (int gameNr, char resChar)
     free(p); appData.results = q;
     if(nextGame <= appData.matchGames && resChar != ' ' && !abortMatch &&
        (gameNr < 0 || nextGame / appData.defaultMatchGames != gameNr / appData.defaultMatchGames)) {
+      int round = appData.defaultMatchGames * appData.tourneyType;
+      if(gameNr < 0 || appData.tourneyType < 1 ||  // gauntlet engine can always stay loaded as first engine
+        appData.tourneyType > 1 && nextGame/round != gameNr/round) // in multi-gauntlet change only after round
        UnloadEngine(&first);  // next game belongs to other pairing;
        UnloadEngine(&second); // already unload the engines, so TwoMachinesEvent will load new ones.
     }
+    if(appData.debugMode) fprintf(debugFP, "Reserved, next=%d, nr=%d, procs=(%x,%x)\n", nextGame, gameNr, first.pr, second.pr);
 }
 
 void
@@ -9954,6 +9958,9 @@ Pairing (int nr, int nPlayers, int *whitePlayer, int *blackPlayer, int *syncInte
            *blackPlayer = curRound + (nPlayers-1)/2 - curPairing;
            if(*blackPlayer >= nPlayers-1+(nPlayers&1)) *blackPlayer -= nPlayers-1+(nPlayers&1);
        }
+    } else if(appData.tourneyType > 1) {
+       *blackPlayer = curPairing; // in multi-gauntlet, assign gauntlet engines to second, so first an be kept loaded during round
+       *whitePlayer = curRound + appData.tourneyType;
     } else if(appData.tourneyType > 0) {
        *whitePlayer = curPairing;
        *blackPlayer = curRound + appData.tourneyType;
@@ -10015,16 +10022,20 @@ NextTourneyGame (int nr, int *swapColors)
        matchGame = 1; roundNr = nr / syncInterval + 1;
     }
 
-    if(first.pr != NoProc || second.pr != NoProc) return 1; // engines already loaded
+    if(first.pr != NoProc && second.pr != NoProc) return 1; // engines already loaded
 
     // redefine engines, engine dir, etc.
     NamesToList(firstChessProgramNames, command, mnemonic); // get mnemonics of installed engines
-    SetPlayer(whitePlayer); // find white player amongst it, and parse its engine line
-    SwapEngines(1);
-    SetPlayer(blackPlayer); // find black player amongst it, and parse its engine line
-    SwapEngines(1);         // and make that valid for second engine by swapping
-    InitEngine(&first, 0);  // initialize ChessProgramStates based on new settings.
-    InitEngine(&second, 1);
+    if(first.pr == NoProc || nr < 0) {
+      SetPlayer(whitePlayer); // find white player amongst it, and parse its engine line
+      InitEngine(&first, 0);  // initialize ChessProgramStates based on new settings.
+    }
+    if(second.pr == NoProc) {
+      SwapEngines(1);
+      SetPlayer(blackPlayer); // find black player amongst it, and parse its engine line
+      SwapEngines(1);         // and make that valid for second engine by swapping
+      InitEngine(&second, 1);
+    }
     CommonEngineInit();     // after this TwoMachinesEvent will create correct engine processes
     UpdateLogos(FALSE);     // leave display to ModeHiglight()
     return 1;