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Stockfish 17062122 - new version!

on
Stockfish, chess engine UCI

Leader rating list JCER = 3372
🔬 Author: Joost VandeVondele

More:
Timestamp: 1498077478 

 Fix four data races. 

 the nodes, tbHits, rootDepth and lastInfoTime variables are read by multiple threads, but not declared atomic, leading to data races as found by -fsanitize=thread. This patch fixes this issue. It is based on top of the CI-threading branch (PR #1129), and should fix the corresponding CI error messages. 

 The patch passed an STC check for no regression: 

 http://tests.stockfishchess.org/tests/view/5925d5590ebc59035df34b9f 
LLR: 2.96 (-2.94,2.94) [-3.00,1.00] 
Total: 169597 W: 29938 L: 30066 D: 109593 

 Whereas rootDepth and lastInfoTime are not performance critical, nodes and tbHits are. Indeed, an earlier version using relaxed atomic updates on the latter two variables failed STC testing (http://tests.stockfishchess.org/tests/view/592001700ebc59035df34924), which can be shown to be due to x86-32 (http://tests.stockfishchess.org/tests/view/592330ac0ebc59035df34a89). Indeed, the latter have no instruction to atomically update a 64bit variable. The proposed solution thus uses a variable in Position that is accessed only by one thread, which is copied every few thousand nodes to the shared variable in Thread. 

 No functional change. 

 Closes #1130 
Closes #1129 


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