Kestrelhttpserver: Kestrel Dasm

[benaadams]

Produced this while looking at something else; might be interesting

Its ngen'd so caveats apply; Vector paths aren't taken and readonly statics aren't consts etc...
https://aoa.blob.core.windows.net/aspnet/Microsoft.AspNetCore.Server.Kestrel.dasm.txt

But should give flavour for what's inlined what's not, how things expand, what is converted to registers what not and why etc...

/cc @davidfowl @halter73 @cesarbs

[halter73]

Cool. How did you create the ngen dasm?

[benaadams]

Twist on https://github.com/dotnet/coreclr/pull/6634#issuecomment-238048694

_Prep_

1. Build coreclr Checked
2. Build jitutils https://github.com/dotnet/jitutils
3. Build standalone app and publish (So it has all the dlls)
4. Copy clrjit.dll from coreclr Checked (coreclr\bin\Product\Windows_NT.x64.Checked) over the one in publish dir

_Iterations_

1. Build app, or lib (e.g. Kestrel)
2. Copy dlls you want to examine over the ones in app publish dir
3. at cmd set set COMPlus_JitPrintInlinedMethods=1
4. run jit-dasm on publish directory (see below)
5. Check the output text file

The command:

jit-dasm --platform MyAppbinReleasenetcoreapp1.0win7-x64publish --base MyAppbinReleasenetcoreapp1.0win7-x64publishcrossgen.exe --output M:outputKDNEW MyAppbinReleasenetcoreapp1.0win7-x64publishMicrosoft.AspNetCore.Server.Kestrel.dll

Would create a dasm file for Microsoft.AspNetCore.Server.Kestrel in M:\output\KDNEW\base

[benaadams]

New info... so if you do the standalone app + publish, then copy the checked clrjit.dll over (Prep)

Then you can just set the set COMPlus_JitPrintInlinedMethods=1 flag and it will output all the inlines when you run it (won't do the dasm though).

Since its actually running it will take the vectors paths etc...

[benaadams]

Also if you set set COMPlus_JitDisasm=* it will dump out all the jitted code when you run normally (using the checked clrjit.dll and everything else from clr Release)

[benaadams]

Ok simplest path... Build coreclr checked and release (can keep using these till you want an new update of coreclr)

coreclr> build all x64 Checked Release skiptests

Build test app as win7-x64 standalone and publish

Copy all files from coreclr\bin\Product\Windows_NT.x64.Release and pdb to your standalone publish directory e.g. bin\Release\netcoreapp1.0\win7-x64\publish

Copy clrjit.dll over from checked coreclr\bin\Product\Windows_NT.x64.Checked into the same publish directory.

Set the enviorment vars
set COMPlus_JitPrintInlinedMethods=1
set COMPlus_JitDisasm=*

Run your standalone exe from the publish directory probably piping its output to a file > dasm.txt

You can also get the jit to only output a certain disassembly e.g. set COMPlus_JitDisasm=System.Generic.*

The jit will work in parallel, so wait for start up to complete before you try loading a page or the output will get interleaved.