Avoid generating machine code repeatly for same basic block #378
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jserv
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| @@ -56,7 +56,8 @@ | |||
| #define JIT_OP_MOD_REG (JIT_CLS_ALU | JIT_SRC_REG | 0x90) | |||
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| #define STACK_SIZE 512 | |||
| #define MAX_INSNS 1024 | |||
| #define MAX_JUMPS 1024 | |||
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Can you show empirical adjustments for both MAX_JUMPS and MAX_INSNS. I wonder how they can be calculated.
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The MAX_JUMPS means the number of host branch instructions within a chained block collection need to be resolved.
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I modified MAX_INSNS into MAX_BLOCKS because it refers to the total number of basic blocks within our code cache. Considering that our block cache size is 4096 and some blocks may be replaced, I set MAX_BLOCKS to 8192.
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Drop the trailing dot in the subject of git commit messages.
See https://cbea.ms/git-commit/
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We set 256 as the threshold because we recorded 16 indirect jumps, and the threshold for launching T1C is 4096. This modification also saves code cache space by avoiding storing the machine code with less usage.
Originally, every execution path had its own machine code. Therefore, even if some basic blocks had been traced in other execution paths, we still generated a new copy of machine code. To use the code cache space more efficiently, we modified the recorded table to be global, allowing every execution path to share the machine code. This modification ensures that every basic block has only one copy of machine code, thus saving code cache space. For example, the code cache stored 1,926,471 (1.9 MB) bytes of machine code for AES previously. After the modification, the code cache stored 182,730 (0.18 MB) bytes of machine code.
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Avoid generating machine code repeatly for same basic block
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Originally, every execution path had its own machine code. Therefore, even if some basic blocks had been traced in other execution paths, we still generated a new copy of machine code. To use the code cache space more efficiently, we modified the recorded table to be global, allowing every execution path to share the machine code. This modification ensures that every basic block has only one copy of machine code, thus saving code cache space.
For example, the code cache stored 1,926,471 (1.9 MB) bytes of machine code for AES previously. After the modification, the code cache stored 182,730 (0.18 MB) bytes of machine code.