Horton

Re: JIT compiling with LLVM v11

Andres Freund <andres@anarazel.de>

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From: Andres Freund <andres@anarazel.de>
To: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Cc: Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2018-03-06T20:29:15Z
Lists: pgsql-hackers 
On 2018-03-06 12:16:01 -0800, Andres Freund wrote:
> > I ran some performance assessments:
> >
> > merge base (0b1d1a038babff4aadf0862c28e7b667f1b12a30)
> >
> > make installcheck  3.14s user 3.34s system 17% cpu 37.954 total
> >
> > jit branch default settings
> >
> > make installcheck  3.17s user 3.30s system 13% cpu 46.596 total
> >
> > jit_above_cost=0
> >
> > make installcheck  3.30s user 3.53s system 5% cpu 1:59.89 total
> >
> > jit_optimize_above_cost=0 (and jit_above_cost=0)
> >
> > make installcheck  3.44s user 3.76s system 1% cpu 8:12.42 total
> >
> > jit_inline_above_cost=0 (and jit_above_cost=0)
> >
> > make installcheck  3.32s user 3.62s system 2% cpu 5:35.58 total
> >
> > One can see the CPU savings quite nicely.
> 
> I'm not quite sure what you mean by that.
> 
> 
> > One obvious problem is that with the default settings, the test suite
> > run gets about 15% slower.  (These figures are reproducible over several
> > runs.)  Is there some debugging stuff turned on that would explain this?
> >  Or would just loading the jit module in each session cause this?
> 
> I suspect it's loading the module.

There's also another issue: For a lot queries in the tests the stats are
way way way off because the relevant tables have never been analyzed.
There's a few cases where costs are off by like 5-7 orders of
magnitude...

Greetings,

Andres Freund

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".