exact alignment with fm-index on the intel xeon phi...

FM-Index Search Algorithm Hardware resources Results Conclusions

Exact Alignment with FM-Index on the Intel XeonPhi Knights Landing Processor

Jose M. Herruzo1 Sonia Gonzalez-Navarro1 Pablo Ibanez2

Vıctor Vinals2 Jesus Alastruey-Benede2 Oscar Plata1

1Departamento de Arquitectura de ComputadoresUniversidad de Malaga

2Grupo de Arquitectura de ComputadoresUniversidad de Zaragoza

Accelerator Architecture in Computational Biology andBioinformatics, 2018


Motivation

Genomic Sequencing

New SequencingTechnologies

Sequence alignment


MotivationIndices

Suffix Tree

Hash Tables

FM-Index


MotivationBWT & FM-Index

Burrows Wheeler Transform(BWT)

FM-Index

BowtieBWASOAP2

banana$

0 banana$

1 anana$b

2 nana$ba

3 ana$ban

4 na$bana

5 a$banan

6 $banana


Outline

1 FM-Index Search AlgorithmSampled FM-IndexK-Step FM-IndexBit-Vector FM-Index

2 Hardware resources

3 ResultsRANDOM BenchmarkThroughput results

4 Conclusions


FM-Index

Data structures

C arrayOcc table

Random memoryaccesses

Memory boundalgorithm

Backward Searchalgorithm

Algorithm: Backward Search Based on FM-index

Input: FM-index of T text (C & Occ), Q query, n:|T|, p:|Q|

Ouput: (sp,ep): Interval pointers of Q in T

begin

1: sp = C[Q[p]]

2: ep = C[Q[p]+1]

3: for i from p-1 to 1 step -1

4: sp = LF(Q[i],sp)

5: ep = LF(Q[i],ep)

6: end for

7: return (sp+1,ep)

end

2 LFop-chains


FM-Index

Lmem Lop

LLFM

MEMLF(Q{p-1},sp) OP

MEM OPLF(Q{p-1},ep)

MEM OP

MEM OP

LF(Q{p-2},sp)

LF(Q{p-2},ep)

idle time

Liter


FM-Index

Lmem Lop

LLFM

MEMLF(Q[1]{p-1},sp) OP

MEM OP

MEM OP

MEM OP

idle time

LF(Q[1]{p-1},ep)

LF(Q[1]{p-2},sp)

LF(Q[1]{p-2},ep)

MEMLF(Q[2]{p-1},sp) OP

MEM OPLF(Q[2]{p-1},ep)

OPLF(Q[Nq]{p-1},ep)

Liter


Outline




4 Conclusions


Sampled FM-Index

Occ

rOcc

d=4

SFM

d=4

d=4

Reduce Memory Footprint↓

Increase computingrequirements

From Ferragina, P. and Manzini, G.: ”Opportunistic DataStructures with Applications” (2000)


Outline




4 Conclusions


K-Step FM-Index

Searching severalsymbols per

iteration

Increasedmemoryfootprint

Reducednumber of LFoperations

C1 4=X

A C G T

2-C1

AA AC AG AT CA CC TTGT

1

1 2 3

1

4=X

rOccA

C

G

T

16=X2

1 2 3

2-rOccAA

AC

AG

AT

CA

CC

TT

1 2 3 n+1

1

2

3

n+1

M

BWT

G C

T C

A A

A G

G T

1

2

3

n+1

GC

TC

AA

AG

GT

2-BWT

From Chacon et al. (2015)


FM-Index Comparison

K1-32S

FM

K1-192

SFM

K1-448

SFM

K2-16S

FM

K2-128

SFM

K2-256

SFM

Implementation

10.0

12.5

15.0

17.5

20.0

22.5

25.0

27.5

30.0

SI (L

FMs/

KB

yte)

0.0 0.0 0.0

26.728.4

20.8

27.6 28.4

15.9

0.0 0.0 0.0


Outline




4 Conclusions


Bit-Vector FM-Index

1 Q{i} X 1 d

SFM row

m%d

F A R R A M S M…………C A F L G A O M D

1 1 d

bvSFM row

m%d

1 0 0 0 0 0 0 0……0 0 1 0 0 0 0 0 0

(m-1)/d +1

F A R M S D

F

Q{i} 1 dm%d

0 0 0 0 0 1 0 1……0 0 0 0 0 0 0 1 0

M

X 1 dm%d

0 0 0 0 0 0 0 0……0 0 0 0 0 0 0 0 1

D


Bit-Vector FM-Index

Advantages

Reduced data movement

Reduced computing requirements

Disadvantages

Increased memory footprint


FM-Index Comparison

K1-32S

FM

K1-192

SFM

K1-448

SFM

K2-16S

FM

K2-128

SFM

K2-256

SFM

K2-64b

vSFM

K2-96b

vSFM

Implementation

10

20

30

40

50

60

SI (L

FMs/

KB

yte)

27.6 28.4

15.9

26.7 28.4

20.8

56.3 56.3


Outline




4 Conclusions


Hardware Resources

Xeon Phi 7210 Xeon E5-2630V4(KNL) (Broadwell)

64 cores @ 1.3 GHz 10 cores @ 2.2 GHz4 threads per core 2 threads per core

400 GB/s (MCDRAM) 68 GB/s (DDR4)

Intel Xeon Phi

AVX 512 VectorialProcessing Units

High Bandwidth Memory(HBM)

Cache / Hybrid / Flat


Outline




4 Conclusions


ResultsXeon Broadwell RANDOM Benchmark

4 8 12 16 20 24 28 32Dependency chains per thread

30

35

40

45

50

55

60

Ban

dwid

th (G

B/s

)

37.93

43.67 43.46 43.51 43.22 43.49 43.16 43.4

44.31 44.77 45.24 45.74 46.58 46.35 45.19 45.76

1 Cache Block2 Cache Block


ResultsXeon Phi KNL RANDOM Benchmark

2 3 4 5 6 8 10 12 14 16Dependency chains per thread

100

150

200

250

300

Ban

dwid

th (G

B/s

)

147.8

197.7209.9 211.3 219.6 217.2 217.6 217.8 216.9 215.5

82.3

108.0 109.6 111.4 112.4 114.5 115.3 117.2 115.0 113.6

1 Cache Block MCDRAM1 Cache Block DDR


Outline




4 Conclusions


ResultsExperimental Setup

Human Genome (Around 3GBases).

20 million input queries generated by Mason.

200 symbols per Sequence.

Measurements started after loading the sequences into mainmemory.

LFM/s as performance evaluation metric


Results

k1-19

2SFM

k1-32

SFM

k2-12

8SFM

k2-16

SFM

k2-96

bvSFM

k2-64

bvSFM

Implementation

0

2

4

6

8

10

12

Perf

orm

ance

(GLF

M/s

)

1.7

4.3

3.2

5.15.9

11.6

0.61.1 1.0 1.2

1.8 2.0

Theoretical limitsIntel Xeon Phi 7210Intel Xeon E5-2630v4


ResultsRoofline (Broadwell)

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14Search Intensity (LFM/Byte)

0

2

4

6

8

10

GLF

M/s

STREAM Peak Bandwidth

RANDOM Peak Bandwidth

Peak LF Performance (8 GLFM/s)

Previous CPU Performance (0.5 GLFM/s)

Previous GPU Performance (3.8 GLFM/s)

Tesla P100 NVBIO Match (2.7 GLFM/s)

K2-16SFM (1.23 GLFM/s)K2-64bvSFM (1.97 GLFM/s)


ResultsRoofline (Knights Landing)

0.00 0.02 0.04 0.06 0.08 0.10 0.12 0.14Search Intensity (LFM/Byte)

0.0

2.5

5.0

7.5

10.0

12.5

15.0

17.5

GLF

M/s

STRE

AM

Pea

k Ba

ndw

idth

RANDOM Pe

ak B

andw

idth

Peak LF Performance (15.10 GLFM/s)

Previous CPU Performance (0.5 GLFM/s)

Previous GPU Performance (3.8 GLFM/s)Tesla P100 NVBIO Match (2.7 GLFM/s)

K2-16SFM (5.1G GLFM/s)K2-64bvSFM (11.6 GLFM/s)


Outline




4 Conclusions


Conclusions

Reduced data movement

Efficiently used memory bandwidth

Great performance improvement

Up to 11.7 G LFM/s3x faster than previous GPU versions


Exact Alignment with FM-Index on the Intel XeonPhi Knights Landing Processor

Jose M. Herruzo1 Sonia Gonzalez-Navarro1 Pablo Ibanez2

Vıctor Vinals2 Jesus Alastruey-Benede2 Oscar Plata1

1Departamento de Arquitectura de ComputadoresUniversidad de Malaga

2Grupo de Arquitectura de ComputadoresUniversidad de Zaragoza

Accelerator Architecture in Computational Biology andBioinformatics, 2018

exact alignment with fm-index on the intel xeon phi...

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