Changeset 27699

Timestamp:

Jun 14, 2023, 9:44:23 AM (14 months ago)

Author:

wraitii

Message:

Turn off SPECTRE mitigation in jit code

SPECTRE attacks mitigations were added to SpiderMonkey's JIT output in version 57. Turning these off is a very large speedup, around 10-20% wall time (on my computer) depending on the map and the situation.
For the most part, from profiling on my machine, this is from memory fences after JIT -> C++ calls. 0 A.D. does a lot of these.

The SPECTRE class of attack is a timing attack based on speculative execution to leak sensitive information, and it seems extraordinarily unlikely that something like this could be successfully mounted using 0 A.D.

Differential Revision: ​https://code.wildfiregames.com/D5014

File:

• ps/trunk/source/scriptinterface/ScriptContext.cpp (modified) (1 diff)

ps/trunk/source/scriptinterface/ScriptContext.cpp

@@ -121 +121 @@
     JS_SetGlobalJitCompilerOption(m_cx, JSJITCOMPILER_BASELINE_ENABLE, 1);
 
+
+
+
+
+
+
+
     JS::ContextOptionsRef(m_cx).setStrictMode(true);