Update Dec 2022: sir-mirjit-base and sir-mirjit branches were merged with Dec 2022 ruby trunk.

What's the branch about

• The branch sir-mirjit is used for development of specialized VM insns (specialized IR or SIR in brief), faster CRuby interpreter and MIR-based JIT (MIRJIT in brief) based on SIR

• The last branch merge point with the trunk is always the head of the branch sir-mirjit-base

  • The branch sir-mirjit will be merged with the trunk from time to time and correspondingly the head of the branch sir-mirjit-base will be the last merge point with the trunk

Specialized VM insns

• Specialized VM insns are generated dynamically in a lazy way and on VM insns BB level only. They consist of
  • hybrid stack-RTL insns:

        sir_{plus,minus,mult,div,mod,or,and,eq,neq,lt,gt,le,ge,aref,aset}s{s,v,i}{s,v,i}

where suffix `s` means value on stack, `v` means local variable value, `i` means immediate value.
Some sufix combinations (like `vii`, `sii`, `sss`) are not permitted.

• type-specialized insns:

        sir_i{plus,minus,mult,div,mod,or,and,eq,neq,lt,gt,le,ge,aref,aset}{s,v}{s,v,i}{s,v,i}
        sir_f{plus,minus,mult,div,mod,eq,neq,lt,gt,le,ge}s{s,v,i}{s,v,i}
        sir_ib{eq,neq,lt,gt,le,ge}{s,v,i}{s,v,i}

where `i` after prefix `sir_` means fixnum insns, and `f` means flonum insns

• speculatively type-specialized insns (with guards):

        sir_si{plus,minus,mult,div,mod,or,and,eq,neq,lt,gt,le,ge,aref,aset}s{s,v,i}{s,v,i}
        sir_sf{plus,minus,mult,div,mod,eq,neq,lt,gt,le,ge}s{s,v,i}{s,v,i}

where `i` after prefix `sir_` means fixnum insns, and `f` means flonum insns

• insns for profiling (e.g. sir_inspect_type or sir_inspect_fixnum)
• different specialized insns for calls (e.g. sir_iseq_send_without_block or sir_cfunc_send)
• attribute manipulation (e.g. sir_send_ivget or sir_send_ivset)
• iterators (sir_iter_{start,body,cont})
• different rarely executed insns to start generation of the specialized IR (e.g sir_make_bbv) or jitting (e.g. sir_bbv_jit_call).
• More details about specialized insns can be found at the end of file insns.def

Project related files

• SIR generation related code can be found in file sir_gen.c
• SIR execution related code can be found in file sir_exec.c and insns.def
• MIRJIT code generation is in file mirjit.c
  • to build MIRJIT you need to build and install MIR-library from branch bbv of MIR project (https://github.com/vnmakarov/mir)

SIR flow

• Normal IR execution flow:
  • Start execution of BB with a stub
  • Stub execution generates hybrid stack-based RTL insns and type-specialized insns with profiling insns
    • Type specialized insns here are generated by basic block versioning (see article by Maxime Chevalier-Boisvert)
  • Several executions of type-specialized insns results in type- and profile- specialized insns
  • Type- and profile-specialized insns are a source of MIRJIT
• Exception IR execution flow:
  • Switching to non-type specialized stack-based RTL

Current state of the project

• The code is made public only for introducing CRuby developers to the project
• The code is only good enough to run optcarrot and micro-benchmarks from directory sir-bench
  • To run benchmarks:
    • optional (for x86-64 mirjit): build and install MIR bbv branch with default install prefix (/usr/local)
      • if you have already installed MIR in /usr/local and want build ruby w/o mirjit, use option --without-mir for ruby configure
    • build ruby from this branch
    • run microbenchmarks:

      cd sir-bench
      ruby compare.rb "<list ruby benchmarks from sir-bench>" base:../miniruby sir:'../miniruby --sir' yjit:'../miniruby --yjit-call-threshold=1' ...

* clone [optcarrot](https://github.com/mame/optcarrot) from github and run it:

      cd sir-bench
      ../miniruby [--sir|--yjit-call-threshold=1|...]  -v -Ilib -r<path-to-optcarrot>/tools/shim <path-to-optcarrot>/bin/optcarrot --benchmark [--opt] -f=3000 <path-to-optcarrot>/examples/Lan_Master.nes

• The status will be changed to reflect the project progress

The current performance SIR interpreter and MIRJIT

• All measurements are done on Intel i7-9700K with 16GB memory under x86-64 Fedora Core32

• I compared the following:

  • base - the base interpreter (miniruby)
  • sir - the interpreter with specialized (miniruby --sir)
  • yjit - YJIT (miniruby --yjit-call-threshold=1)
  • mjit - MJIT (ruby --mit-call-threshold=2)
  • mir - MIR-based JIT (miniruby --mirjit)

• I used the following micro-benchmarks (see MJIT-benchmarks directory):

  • aread - reading an instance variable through attr_reader
  • aref - reading an array element
  • aset - assignment to an array element
  • awrite - assignment to an instance variable through attr_writer
  • bench - rendering
  • call - empty method calls
  • complex-mandelbrot - complex mandelbrot
  • const2 - reading Class::Const
  • const - reading Const
  • fannk - fannkuch
  • fib - fibonacci
  • ivread - reading an instance variable (@var)
  • ivwrite - assignment to an instance variable
  • mandelbrot - (non-complex) mandelbrot as CRuby v2 does not support complex numbers
  • meteor - meteor puzzle
  • nbody - modeling planet orbits
  • nest-ntimes - nested ntimes loops (6 levels)
  • nest-while - nested while loops (6 levels)
  • norm - spectral norm
  • pent - pentamino puzzle
  • red-black - Red Black trees
  • sieve - Eratosthenes sieve
  • trees - binary trees
  • while - while loop

• Each benchmark ran 3 times and minimal time (or smallest maximum resident memory) was chosen

• I also used optcarrot for more serious program performance comparison

  • I used 3000 frames to run optcarrot

Microbenchmark results (Nov. 10, 2022)

• Wall time speedup:

Elapsed time:

	base	sir	mjit	yjit	mir
aread.rb	1.0	4.35	2.02	4.62	6.1
aref.rb	1.0	3.92	3.54	4.06	6.05
aset.rb	1.0	3.11	2.22	2.37	4.76
awrite.rb	1.0	3.51	1.95	2.16	4.55
bench.rb	1.0	1.34	1.04	1.62	1.33
call.rb	1.0	2.24	5.75	3.71	3.34
complex-mandelbrot.rb	1.0	1.15	1.11	1.39	1.15
const2.rb	1.0	2.82	6.34	3.75	3.02
const.rb	1.0	2.83	6.34	3.75	3.02
fannk.rb	1.0	1.18	0.88	1.0	1.19
fib.rb	1.0	2.15	2.52	3.98	2.77
ivread.rb	1.0	1.83	3.61	3.16	3.08
ivwrite.rb	1.0	3.41	4.58	3.47	3.79
mandelbrot.rb	1.0	1.56	1.17	1.6	1.59
meteor.rb	1.0	1.28	1.04	1.33	1.25
nbody.rb	1.0	1.47	1.24	1.51	1.45
nest-ntimes.rb	1.0	2.03	1.29	1.21	2.4
nest-while.rb	1.0	4.92	3.22	4.27	9.51
norm.rb	1.0	1.44	1.56	1.58	1.69
pent.rb	1.0	1.06	1.01	1.04	0.89
red-black.rb	1.0	1.67	0.87	3.07	1.9
sieve.rb	1.0	2.46	2.0	2.36	2.79
trees.rb	1.0	1.26	1.14	1.77	1.35
while.rb	1.0	4.27	4.93	2.78	5.55
GeoMean.	1.0	2.14	2.05	2.3	2.55

---

• CPU time improvements is aprroximately the same except MJIT which has lower CPU time improvement

---

• Geomean max resident memory increase relative to the base interpreter:

	base	sir	mjit	yjit	mir
GeoMean.	1.0	1.16	3.61	1.03	2.18

---

Optcarrot results

• Frame per seconds (more is better):

	base	sir	yjit	mjit	mir
optcarrot	49.5	73.0	89.5	119.3	77.2
optcarrot --opt	159.4	240.5	22.2	164.1	263.1