Deoptimizing Ruby

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| Deop@mizing Ruby JRuby+Truﬄe and the an@dote to JITs Chris Seaton @ChrisGSeaton Oracle Labs John Tenniel illustra@ons public domain in the UK and US

| Safe Harbor Statement The following is intended to provide some insight into a line of research in Oracle Labs. It is intended for informa@on purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or func@onality, and should not be relied upon in making purchasing decisions. Oracle reserves the right to alter its development plans and prac@ces at any @me, and the development, release, and @ming of any features or func@onality described in connec@on with any Oracle product or service remains at the sole discre@on of Oracle. Any views expressed in this presenta@on are my own and do not necessarily reﬂect the views of Oracle. 3

| chrisseaton.com/rubytruﬄe/deop@mizing 4

| 5 A new open source implementa@on of Ruby by Oracle Labs with a JIT using next-‐gen JVM technology and par6al evalua6on, now part of JRuby JRuby+Truﬄe

| 6 codon.com/compilers-‐for-‐free Presenta@on, by Tom Stuart , licensed under a Crea@ve Commons A\ribu@on ShareAlike 3.0

| Why is Ruby hard to op@mize? 7

| Fixnum to Bignum promo@on Monkey patching methods #binding ObjectSpace set_trace_func Thread#raise 8

| 9 Deop@miza@on elegantly solves all these problems

| 10 Slow interpreter Fast JITed code

| 11 Slow interpreter Fast JITed code

| Illustra@ng Deop@miza@on 12

| 13 John Tenniel illustra@ons public domain in the UK and US

| 16 John Tenniel illustra@ons public domain in the UK and US Ruby Door to utopia of high performance

| 17 John Tenniel illustra@ons public domain in the UK and US Just-‐in-‐@me compiler Leh something behind when we compiled

| 18 John Tenniel illustra@ons public domain in the UK and US Deop@miza@on reverses the eﬀects of the JIT

| What does deop@miza@on do for Ruby? 19

| Fixnum to Bignum promo@on 20

| 21 a + b + c We’ll assume we already know these are Fixnums

| 22 t1 = Fixnum(a) + Fixnum(b) if t1.overflowed? t1 = Bignum(a) + Bignum(b) t2 = Bignum(t1) + Bignum(c) else t2 = Fixnum(t1) + Fixnum(c) if t2.overflowed? t2 = Bignum(t1) + Bignum(c) end end

| 23 t1 = Fixnum(a) + Fixnum(b) deoptimize! if t1.overflowed? t2 = Fixnum(t1) + Fixnum(c) deoptimize! if t2.overflowed?

| 24 t1 = Fixnum(a) + Fixnum(b) if t1.overflowed? t1 = Bignum(a) + Bignum(b) t2 = Bignum(t1) + Bignum(c) else t2 = Fixnum(t1) + Fixnum(c) deoptimize! if t2.overflowed? end

| Monkey patching methods 25

| 26 my_object.my_method(x, y)

| 27 lookup my_method in my_object call it with (x, y)

| 28 if my_object.changed? lookup my_method in my_object call it with (x, y) else use cached my_method call it with (x, y) end

| 29 if my_object.changed? deoptimize! else use cached my_method call it with (x, y) end

| 30 use cached my_method call it with (x, y)

| #binding 31

| 32 a = 14 b = [8.2, 3.4]

| 33 … a: 14 Array 0: 1: 8.2 3.4 b: …

| 34 … a: 14 b[0]: 8.2 … b[1]: 3.4

| 35 14 Array 0: 1: 8.2 3.4 … … a: 14 b[0]: 8.2 b[1]: 3.4

| ObjectSpace set_trace_func 36

| How JRuby+Truﬄe Deop@mizes 37

| 38 1.  Recreate the interpreter stack frame 2.  Jump from the JITed code into the interpreter 3.  Allow us to force threads to do this

| 39 loop do a = 14 b = 2 a + b end

| 40 loop do a = 14 b = 2 a + b deoptimize! if should_deoptimize? end

| 41 loop do a = 14 b = 2 a + b read the safepoint page end

| JRuby+Truﬄe Performance 42

| 86% RubySpec language specs rubyspec.org, Brian Shirai et al 43

| 44 Fixnum to Bignum promo@on #eval #binding Proc#binding #send ObjectSpace set_trace_func Thread#raise Float Closures C extensions Threads Concurrency Frame-‐local variables Encodings Debugging Method invalida@on Constant invalida@on Regexp

| 45 Fixnum to Bignum promo@on #eval #binding Proc#binding #send ObjectSpace set_trace_func Thread#raise Float Closures C extensions Threads Concurrency Frame-‐local variables Encodings Debugging Method invalida@on Constant invalida@on Regexp

| 46 No, we can’t run Rails yet but we’re working towards it

| 47

| 48 chunky_png and psd.rb Willem van Bergen, Ryan LeFevre, Kelly Su\on, Layer Vault, Floorplanner et al Ruby logo copyright (c) 2006, Yukihiro Matsumoto, licensed under the terms of the Crea@ve Commons A\ribu@on-‐ShareAlike 2.5 agreement

| 49

| 50

| Conclusions 51

| Building on other projects 52 JRuby logo copyright (c) Tony Price 2011, licensed under the terms of the Crea@ve Commons A\ribu@on-‐NoDerivs 3.0 Unported (CC BY-‐ND 3.0) Ruby logo copyright (c) 2006, Yukihiro Matsumoto, licensed under the terms of the Crea@ve Commons A\ribu@on-‐ShareAlike 2.5 agreement Rubinius logo licensed under the terms of the Crea@ve Commons A\ribu@on-‐NoDerivs 3.0 Unported

| 53

| @ChrisGSeaton chrisseaton.com/rubytruﬄe/deop@mizing 54

| Safe Harbor Statement The preceding is intended to provide some insight into a line of research in Oracle Labs. It is intended for informa@on purposes only, and may not be incorporated into any contract. It is not a commitment to deliver any material, code, or func@onality, and should not be relied upon in making purchasing decisions. Oracle reserves the right to alter its development plans and prac@ces at any @me, and the development, release, and @ming of any features or func@onality described in connec@on with any Oracle product or service remains at the sole discre@on of Oracle. Any views expressed in this presenta@on are my own and do not necessarily reﬂect the views of Oracle. 55

| 56

Deoptimizing Ruby

Deoptimizing Ruby

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