Horton

Re: JIT compiling with LLVM v12

Noah Misch <noah@leadboat.com>

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From: Noah Misch <noah@leadboat.com>
To: Andres Freund <andres@anarazel.de>
Cc: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>, pgsql-hackers@postgresql.org
Date: 2018-09-06T02:26:51Z
Lists: pgsql-hackers 
On Wed, Sep 05, 2018 at 11:55:39AM -0700, Andres Freund wrote:
> On 2018-08-22 06:20:21 +0000, Noah Misch wrote:
> > I see jit slows the regression tests considerably:
> 
> Is this with LLVM assertions enabled or not?

Without, I think.  I configured them like this:
cmake -G Ninja -DCMAKE_INSTALL_PREFIX=$HOME/sw/nopath/llvm       -DCMAKE_BUILD_TYPE=MinSizeRel -DLLVM_USE_LINKER=gold -DLLVM_TARGETS_TO_BUILD=X86 ../llvm
cmake -G Ninja -DCMAKE_INSTALL_PREFIX=$HOME/sw/nopath/llvm-el32  -DCMAKE_BUILD_TYPE=MinSizeRel -DLLVM_USE_LINKER=gold -DLLVM_PARALLEL_LINK_JOBS=1 ../llvm

> > # mips32el, assert, w/o llvm (buildfarm member topminnow) [1]
> > 28min install-check-*
> > 35min check-pg_upgrade
> >
> > # mips32el, assert, w/  llvm 6.0.1 [1]
> >  63min install-check-*
> > 166min check-pg_upgrade
> 
> But this seems so absurdly large of a difference that I kinda think LLVM
> assertions (wich are really expensive and add O(N) operations in a bunch
> of places) might be to blame.

The 2018-08-25 and 2018-09-01 published runs were far less bad.  Most of the
blame goes to the reason given in the footnote (competing load on a shared
machine), not to JIT.

Commits

  1. Improve JIT docs.

  2. Add documentation for the JIT feature.

  3. Add EXPLAIN support for JIT.

  4. Add inlining support to LLVM JIT provider.

  5. JIT tuple deforming in LLVM JIT provider.

  6. Add FIELDNO_* macro designating offset into structs required for JIT.

  7. Add expression compilation support to LLVM JIT provider.

  8. Expand list of synchronized types and functions in LLVM JIT provider.

  9. Add helpers for emitting LLVM IR.

  10. Basic planner and executor integration for JIT.

  11. Debugging and profiling support for LLVM JIT provider.

  12. Support for optimizing and emitting code in LLVM JIT provider.

  13. Add file containing extensions of the LLVM C API.

  14. Basic JIT provider and error handling infrastructure.

  15. Add configure infrastructure (--with-llvm) to enable LLVM support.

  16. Add C++ support to configure.

  17. Add PGAC_PROG_VARCC_VARFLAGS_OPT autoconf macro.

  18. Fix VM buffer pin management in heap_lock_updated_tuple_rec().

  19. Allow tupleslots to have a fixed tupledesc, use in executor nodes.

  20. Expression evaluation based aggregate transition invocation.

  21. Perform slot validity checks in a separate pass over expression.

  22. Rely on executor utils to build targetlist for DML RETURNING.

  23. Refer to OS X as "macOS", except for the port name which is still "darwin".