Make EntryPointInfo::callsCount usable by redeferral heuristic. #1757
Make EntryPointInfo::callsCount usable by redeferral heuristic. #1757pleath wants to merge 1 commit intochakra-core:masterfrom
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…e the uint8's toi uint32's, which in turn allows us to dispense with the full-JIT code that saturates these values at 255.
| return callCount == 0 ? | ||
| static_cast<uint16>(simpleJitLimit) : | ||
| static_cast<uint16>(simpleJitLimit) - callCount - 1; | ||
| static_cast<uint16>(simpleJitLimit) - static_cast<uint8>(callCount) - 1; |
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static_cast(callCount) [](start = 50, length = 29)
won't this give wrong values for callCount>255?
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The call count can't be > 255 while we're decrementing from the simple JIT limit toward zero. We could probably do without the static cast, but I didn't want any static tools complaining about overflow.
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IIRC, the reason for saturating the call count at 255 was that if it were allowed to grow to uin32_max, and we started bailing out, it will take a long time for the call count to get to 0 and, in turn, for us to rejit the function. Is that not a concern anymore? |
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I think @LouisLaf had an idea for mitigating this. Should be easy to add it later. |
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| // bcs $overflow | ||
| Lowerer::InsertBranch(Js::OpCode::BrLt_A, true, overflowLabel, overflowLabel); | ||
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With int32, I think we don't even care about the overflow. Plus, with saturation, it doesn't fix the retiring problem, it just delays it.
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| Js::FunctionEntryPointInfo *entryPointInfo = function->GetFunctionEntryPointInfo(); | ||
| uint8 callsCount = entryPointInfo->callsCount; | ||
| uint32 callsCount = entryPointInfo->callsCount; |
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You can just change this to:
uint32 callsCount = MIN(entryPointInfo->callsCount, 255);
to retain the previous bailout behavior we had with saturation.
| entryPointInfo->totalJittedLoopIterations = UINT8_MAX; | ||
| } | ||
| uint8 totalJittedLoopIterations = (uint8)entryPointInfo->totalJittedLoopIterations; | ||
| uint32 totalJittedLoopIterations = entryPointInfo->totalJittedLoopIterations; |
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uint32 totalJittedLoopIterations = entryPointInfo->totalJittedLoopIterations; [](start = 4, length = 77)
In keeping with @LouisLaf 's suggestion in ScheduleFunctionCodeGen, we should retain the existing code here.
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Change the uint8's toi uint32's, which in turn allows us to dispense with the full-JIT code that saturates these values at 255.