Presentation WT-4065, Superconductor: GPU Web Programming for Big Data Visualization, by Leo Meyerovich and Matthew Torok at the AMD Developer Summit (APU13) Nov. 11-13, 2013.

1. SUPERCONDUCTOR
A Browser Framework for
Visualizing Big Data
Leo
Meyerovich,
Ma.
Torok,
Ras
Bodik
@LMeyerov
UC
Berkeley
/
Graphistry
1

2. Why Big Data Visualization?
Yes
No

3. Analysis
Result:
No
3

4. Histogram of Voter Turnout by Town
who’s ballot
stuffing?
# Towns
most towns had
a 40% voter
turnout
0%
75%
25%
100%
50%
Voter turnout
4

5. Tree Map Demo

6. Ex: Time Series in IBM’s IT Monitor

7. GE Demo

8. Browser Engine ~= Chart Engine!
DSLs
render
layout
selectors
parse
Exploit Parallelism in Each One

9. Deploy Today via Parallel JavaScript
data
styling
widgets
Parser.js
GPU
Compiler
Data
stays
on
GPU!
Selectors.CL
Layout.CL
JavaScript
VM
data
viz
Renderer.GL
webpage
Parser
Selectors
HTML
data
CSS
styling
JS
script
Layout
Renderer
Pixels
superconductor.js
9

10. DSL 1: Data via JSON
JavaScript, Ruby, Python,
Java, …
Easy… until 1-10s data
loading
10

11. Parsing Demo
11

12. DSL 2: Designers
Selectors
<div>
<span>
<b>
<i>
<p>
<b>
<img
class=“dog”>
<b>
span
b
{
width:
83%
}
div
.dog
{
float:
leJ
}
p
,
span
b
{
font-­‐size:
7px
}
12

13. Problem: O(sels * tree log tree )
<div>
1K-100K HTML nodes
<span>
<p>
×
<b>
<i>
1-10K selectors
<b>
<img
class=“dog”>
<b>
span
b
{
width:
83%
}
div
.dog
{
float:
leJ
}
p
,
span
b
{
font-­‐size:
7px
}
13

14. Good News: Embarrassing Parallelism!
<div>
<span>
<b>
<i>
<p>
<b>
<img
class=“dog”>
<b>
span
b
{
width:
83%
}
div
.dog
{
float:
leJ
}
p
,
span
b
{
font-­‐size:
7px
}
14

15. Selector Engine Implementation
selectors.css
Dynamic Animation!
edit style at runtime
then recompile
compiler.js
selectors.webcl
…

16. DSL 3: Layout
CSS
JS
parallelizable layout
flexible compute
FTL
parallelizable compute in declarative layout

17. Step
1/2:
Schema
of
VisualizaYon
Tree class hierarchy
Node attributes
17

18. [Kastens
1980,
Saraiva
2003]
[WWW
2010,
Step 2/2: Schema AttributePPOPP
2013]
Constraints
1. Local
10px
5px
inputs
vars
2.
Single-­‐assignment
HBox
Leaf
y
w
h
x
Leaf
y
w
h
x
y
w
h
x
HBox
HBox ! left=IBox right=IBox
w := left.w + right.w
…
Root
y
w
h
x
Leaf
y
w
h
x
Leaf
y
w
h
x
18

19. llel
ara
P
[WWW
2010]
Compiler Output: Layout as Tree Traversals
logical
joins
w,h
w,h
w,h
Leaf
x,y
…
logical
spawns
w,h
w,h
w,h
Parallelism in each traversal!
Mozilla, Microsoft
1. Works for all data sets
2. Compiler automatically parallelizes!
19

20. DSL 4: Rendering as a Layout Extension
HBox ! left=IBox right=IBox
@render @Rectangle(x,y,w,h,color)
…
w := left.w + right.w
…

21. [Blelloch
93]
Traversals: Flattened & Level-Synchronous
y
x
wh
Array per
attribute
level
1
Nodes in
arrays
parallel for loop
(level synchronous)
level
n
Tree
Compiler automates code + data
transformations.
21

22. Problem: Dynamic Memory Allocation on GPU?
rect(…); …
oval(…)
square(…)
function circ(x,y,r) {
buffer = new
line(…); … Array(r*10)
for (i = 0; i < r * 10; i+
circ(…)
+)
buffer[i] =
dynamic
Math.cos(i) allocation"
rect(…); …}
1.0 0.8 0.5 0.2 0
0.2
22

23. Dynamic Allocation as SIMD Traversals
allocRect(…)! 7
fillRect(…)
allocLine(…)! 6
allocCirc(…)à
4
allocRect(…)! 6
1.0 0.8 0.5 0.2 0
0.2
1.0 0.8 0.5
0.2
1. Prefix sum for needed
space
2. Allocate buffers
fillLine(…)
fillCirc(…)
fillRect(…)
1.0 0.8 0.5 0.2 0
0.2
3. Fill vertex buffers in
parallel
4. Give OpenGL buffers
pointer
23

24. CPU vs. GPU for Election Treemap:
5 traversals over 100K nodes
Naïve JS (Chrome 26)
10,000
GPU (Safari + WebCL 11/3)
COMBINED: 54X !
Time (ms)
1,000
100
24fps
WebCL:
5X
WebCL:
31X
10
1
layout (4 passes) rendering pass
TOTAL
24

25. DSLs for Big Data Visualization, Today.

26. Superconductor
• Explore data with interactive visualization
• Script charts like web pages: DSLs!
• Hardware accelerate each DSL
• We use WebCL:
GPGPU, keeps data on GPU, dynamic
compilation

27. Find us!
sc-lang.com
Leo: @LMeyerov / LMeyerov@gmail.com
Matt: mtorok@berkeley.edu

28. Extra

29. Parsing Demo
29

30. Optimizing JSON Parsing
raw.json: 23MB
Parallel parsing easy!
… when you fix the format
partition
raw1.json(1.9MB), …, raw12.json
compress +
zip
csr1.zip (0.2MB), …, csr12.zip
server
browser
Each worker:
parallel parse
parallel parse 1. native JSON parse # csr.jso
parallel parse
2. decompress # obj.json
3. 0-copy return: typed arrays!
big JavaScript
object
30