Upgrade to Pro
— share decks privately, control downloads, hide ads and more …
Speaker Deck
Features
Speaker Deck
PRO
Sign in
Sign up for free
Search
Search
Server Memory - Chernivtsi JS 2019
Search
Андрей Листочкин (Andrey Listochkin)
June 22, 2019
Programming
1
150
Server Memory - Chernivtsi JS 2019
Андрей Листочкин (Andrey Listochkin)
June 22, 2019
Tweet
Share
More Decks by Андрей Листочкин (Andrey Listochkin)
See All by Андрей Листочкин (Andrey Listochkin)
Everybody Stand Back! I Know Regular Expressions
listochkin
0
170
Command-line scripting with Rust. Wait, what?!
listochkin
0
350
Server Memory - BuildStuff Ukraine 2019
listochkin
0
38
10 Years Later
listochkin
0
360
Managing Managers - DevTalks iHUB
listochkin
0
54
Time, Numbers, Text
listochkin
1
580
Software Licensing: A Minefield Guide
listochkin
0
140
We Make Bots. For Real
listochkin
0
420
Devops for A Busy Developer - XP Days 2016
listochkin
0
180
Other Decks in Programming
See All in Programming
WebViewの現在地 - SwiftUI時代のWebKit - / The Current State Of WebView
marcy731
0
110
Google Agent Development Kit でLINE Botを作ってみた
ymd65536
2
220
ふつうの技術スタックでアート作品を作ってみる
akira888
0
440
5つのアンチパターンから学ぶLT設計
narihara
1
160
Team topologies and the microservice architecture: a synergistic relationship
cer
PRO
0
1.2k
A full stack side project webapp all in Kotlin (KotlinConf 2025)
dankim
0
100
PostgreSQLのRow Level SecurityをPHPのORMで扱う Eloquent vs Doctrine #phpcon #track2
77web
2
500
AIエージェントはこう育てる - GitHub Copilot Agentとチームの共進化サイクル
koboriakira
0
500
Kotlin エンジニアへ送る:Swift 案件に参加させられる日に備えて~似てるけど色々違う Swift の仕様 / from Kotlin to Swift
lovee
1
260
既存デザインを変更せずにタップ領域を広げる方法
tahia910
1
280
ruby.wasmで多人数リアルタイム通信ゲームを作ろう
lnit
3
440
CursorはMCPを使った方が良いぞ
taigakono
1
240
Featured
See All Featured
Stop Working from a Prison Cell
hatefulcrawdad
270
21k
A Modern Web Designer's Workflow
chriscoyier
694
190k
Bash Introduction
62gerente
614
210k
Visualization
eitanlees
146
16k
JavaScript: Past, Present, and Future - NDC Porto 2020
reverentgeek
48
5.4k
Building Applications with DynamoDB
mza
95
6.5k
Adopting Sorbet at Scale
ufuk
77
9.4k
Visualizing Your Data: Incorporating Mongo into Loggly Infrastructure
mongodb
46
9.6k
Distributed Sagas: A Protocol for Coordinating Microservices
caitiem20
331
22k
ReactJS: Keep Simple. Everything can be a component!
pedronauck
667
120k
It's Worth the Effort
3n
185
28k
A designer walks into a library…
pauljervisheath
207
24k
Transcript
None
@listochkin fb.com/tektonna
Not a JavaScript talk
No CSS No frameworks No Node
A bit deeper than most talks on similar subject
None
How programming languages work
Just-in-time compilers Garbage Collection
Memory Management
Server runs our programs
CPU Caches RAM Swap Disk Network
Operating System
None
Pages
4k
Virtual
2 processes [0 … ∞]
Oh, I got a pointer at 4096 What’s at 4095?
Page fault
Allocate page But not really
Once you start writing to it
not 4k?
None
None
malloc
None
malloc me some memory
a pointer
free(pointer)
malloc malloc malloc free malloc free free
Forget to free Free the wrong pointer Read from unallocated
memory
Can we do better?
Reference Counting
None
const players = [ … ] players.forEach(p => makeMove(p))
a = … doX(a) yield a
scope
if ( … ) { let a = … …
}
None
C++: std::shared_ptr
None
Optimizations
Delayed Counting
Don’t count local references
function (user) { let email = user.email; … … }
Delayed deallocation
Cycle Collector
None
None
Compile time ref-counting
Several types of pointers
Ownership
Forbids cycles by forbidding several owning references at the same
time
None
None
None
Perl 1987 - today Python 1991 - 2001 PHP 1994
- 2009
Multiprocess deploys
fork
Copy on Write
Worker Accepts requests As memory use raises: Stop accepting requests
Complete in-flight requests Terminate
Master Keep track on workers Start new workers Signal them
to terminate when memory pressure is high
“Pre-fork”
Load the framework Load app code Run full GC Start
forking process to accept requests
None
None
“Processes”
Tracing GC
1959 60 years ago
Start at Root references Follow all references Build a live
objects tree Delete all objects not part of the tree
Ruby Java JavaScript Lua Go
Roots?
Constants Global variables Local variables Closures Thread-locals ...
Mark & Sweep vs Mark-Compact
None
Can you move objects after mark?
Team Sweep: Go Ruby* Lua Embedded JS engines Erlang
Pros: Pointers don’t change Native extensions Easier to implement
Team Compact: Java JavaScript Ruby* Haskell
Pros: Less memory fragmentation over time Cons: Harder Takes longer
to do a GC
Mark all memory
None
Incremental Marking
3-colored algorithm by Dijkstra™
None
None
None
None
None
What is a barrier? if statement
else branch is very rare CPU branch predictor
Parallel marking
None
None
Lazy Sweep
Generational
Temporary data
Major vs Minor GC
Pointers from Old objects to new objects
Remembered Set
Major GC Scan roots only Bigger object graph
Minor GC Scan roots + RS Small object graph
None
Modern GCs are hybrid
None
None
C-extensions
Can’t move objects if their references are passed to an
extension
Can’t add WB
RGen GC
2 types of objects WB-protected WB-unprotected
WBu are never OldGen
OldGen -> WBu WBu to Remembered Set
Mark WBus on every minor GC
1 stw to mark all WBu in RS
None
None
Adding compaction for WBp
None
V8
Minor GC Parallel
Major Parallel marking Parallel / Concurrent Compact || Sweep
None
When to trigger GC?
Out-of-Bounds GC
request? Minor GCs response is sent? Major GC
Firefox Run GC in background tabs first instead of current
tab
Chrome Animation frame
Walking the memory
Cache locality
GPU
OS Pages pre-forked processes malloc zones GC Pages Remembered Sets
Barriers
None
None