JIT: preliminary version of profile-based inline policy #44427
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Add a new inline policy that can be used when a method has profile data. It uses the call site frequency to boost profitability. Size and per-call benefit are currently using the estimates done by the model policy. Not on by default. Set COMPlus_JitInlinePolicyProfile=1 to enable. Add testing to weekly experimental runs.
Dotnet-GitSync-Bot added the area-CodeGen-coreclr 
| cc @dotnet/jit-contrib |
| So it fixes #41923 (I've just checked) 🎉 Also, is it expected that it's now able to inline methods with more than string Foo() => "hello"; [MethodImpl(MethodImplOptions.NoInlining)] bool DoWork() { return Foo() == "hello"; }Currently, inliner gives up here because G_M53056_IG01: sub rsp, 40 ;; bbWeight=1 PerfScore 0.25 G_M53056_IG02: mov rcx, 0xD1FFAB1E mov rdx, gword ptr [rcx] mov rcx, rdx call System.String:Equals(System.String,System.String):bool nop ;; bbWeight=1 PerfScore 3.75 G_M53056_IG03: add rsp, 40 retYour branch (with profile): G_M53056_IG01: ;; offset=0000H ;; bbWeight=1 PerfScore 0.00 G_M53056_IG02: ;; offset=0000H B801000000 mov eax, 1 ;; bbWeight=1 PerfScore 0.25 G_M53056_IG03: ;; offset=0005H C3 ret(basically, fixes #33338) |
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One fix needed in config value string, otherwise LGTM
src/coreclr/src/jit/inlinepolicy.h Outdated
| class ProfilePolicy : public DiscretionaryPolicy | ||
| { | ||
| public: | ||
| // Construct a ModelPolicy |
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nit: copy-paste comment
| | ||
| CONFIG_INTEGER(JitInlinePolicyModel, W("JitInlinePolicyModel"), 0) | ||
| CONFIG_INTEGER(JitInlinePolicyProfile, W("JitInlinePolicyProfile"), 0) | ||
| CONFIG_INTEGER(JitInlinePolicyProfileThreshold, W("JitInlinePolicyProfile"), 40) |
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String is wrong here: JitInlinePolicyProfile => JitInlinePolicyProfileThreshold
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Thanks for spotting this.
Yes. I'm aiming to have very few arbitrary early limits on what might be inlined, to let the profile data and heuristics determine what's best. We will need to have some limit on the max IL size we'll consider so that we don't spend time analyzing large methods that can't possibly be good inlines. Not sure what the right value for that limit is just yet; I have it set to 1000 bytes here. |
| Failure seems unrelated; none of this code should be enabled by default. |
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Add a new inline policy that can be used when a method has profile data.
It uses the call site frequency to boost profitability. Size and per-call
benefit are currently using the estimates done by the model policy.
Not on by default. Set COMPlus_JitInlinePolicyProfile=1 to enable.
Add testing to weekly experimental runs.