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# Tests and tools for ENEA GRID PowerPoint PPT Presentation

Tests and tools for ENEA GRID. Performance test: HPL (High Performance Linpack) Network monitoring. Funel December 11, 2007. HPL TEST. HPL measures the floating point execution rate for solving a sistem of linear equations A X = B

Tests and tools for ENEA GRID

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## Tests and tools for ENEA GRID

Performance test: HPL (High Performance Linpack)

Network monitoring

• Funel

• December 11, 2007

### HPL TEST

• HPL measures the floating point execution rate for solving a sistem of linear equations AX = B

• HPL requires the availibility of MPI and libraries for linear algebra (BLAS, VSIPL, ATLAS)

• HPL is scalable: parallel efficiency constant with respect to the processor memory usage

www.netlib.org/benchmark/hpl

### HPL Results (1)

• A(nn) X = B

• GFLOPS = [(2/3)n3+(3/2)n2]/[th 109]

• th = CPU time

• Th. Peak =

• # of CORES CPU CLOCK SPEED 

• FPO ISSUE RATE

LSF SUBMITION

Linux (bw305): 15 CORES,

Th. Peak = 72 GFLOPS

Test completed

AIX (sp4-2): 32 CORES,

Th. Peak  96 GFLOPS

AIX (sp4-3-4): 32 CORES

Th. Peak =  122 GFLOPS

Test did not complete!!!

### HPL Results (2)

Expected CPU time th : # FPO / (# of CORES  CPU CLOCK SPEED  FPO ISSUE RATE)

USED: ATLAS Version 3.6

Linux (bw305), PQ = 35 CORES (LSF SUBMITION) (HPL COMPLETED)

HIGH USER WAIT TIME (NOT CPU TIME)  MAYBE DUE TO THE NETWORK INTERCONNECTS (PUBLIC WHEN THE TEST WAS DONE)

### A PONT-TO-POINT COMMUNICATION TEST USING MPI

HPL POINT-TO-POINT COMMUNICATION BETWEEN PROCESSORS IS BASED ON MPI (MPI_Send MPI_Recv) ROUTINES

### HPL Results (3)

PROBLEMS FOR AIX (LSF SUBMITION) HPL MAKES THE MACHINES HANGING OUT, THE TEST DOES NOT COMPLETE EVEN IF MEMORY USAGE < 10%

ONLY A FEW CPU SECONDS OVER DAYS OF RUNNING TIME!!!  UNDER INVESTIGATION

INTERACTIVE SUBMITIONS

AIX (sp4-1), 48=32 CORES HPL COMPLETED

ll

AIX (sp4-2), 48=32 CORES, 20% TOTAL (32 GB) MEMORYHPL NOT COMPLETED

AIX (ostro), 44=16 CORES, 20% TOTAL (16 GB) MEMORYHPL NOT COMPLETED

### NETWORK MONITORING (coll. G. Guarnieri)

A TOOL HAS BEEN PROVIDED IN ORDER TO DETECT WHETHER THE COMMUNICATION SPEED BETWEEN TWO HOSTS (CLIENT AND SERVER) OF THE ENEA GRID CHANGES OVER TIME

THE TEST MEASURES THE ROUND TRIP TIME IT TAKES TO SEND A SMALL

PACKET (10, 100, 1000 BYTES) OF DATA AND RECEIVE IT BACK

SMALL PACKETS: NOT CHOPPED (NO SPURIOUS DELAY EFFECTS), FAST

FLUCTUATIONS NOT HIDDEN BY THE FINAL INTEGRATED AVERAGE TIME

NEEDED FOR WAITING BIG SIZE PACKETS

60 PACKETS SENT IN SEQUENCE EACH SECOND

TCP/IP PROTOCOL

client

server

start

BOTH CLIENT AND SERVER BLOCK UNTIL

NO LOSS OF DATA

stop

www.afs.enea.it/funel

### NETWORK MONITORING (2)

Client: eurofel00 Server: bw305-2

Client: kleos Server: feronix0

HIGH SPIKES CLEARLY DETECTED OVERALL COMMUNICATION DELAY

### Conclusions

• HPL BENCHMARK TEST:

• Linux (LSF) THE TEST COMPLETES HOWEVER:

• OBTAINED CPU TIME >> EXPECTED CPU TIME  (PEAK)exp < (PEAK)th

• TOO MUCH (USER) TIME TO COMPLETE

• AIX (LSF)  THE TEST DOES NOT COMPLETE:

• ONLY A FEW CPU SECONDS OVER DAYS OF RUNNING TIME!!!!

• AIX (INTERACTIVE SUBMITION):

• ONLY sp4-1 (32 CORES, 10% TOTAL MEMORY) TESTED 

• TEST COMPLETED BUT STILL (CPU TIME) >> (EXPECTED CPU TIME)

• USER WAIT TIME  35 minutes

NETWORK MONITORING:

A TOOL HAS BEEN PROVIDED TO DETECT VARIATIONS IN THE COMMUNICATION SPEED BEWTEEN TWO HOSTS OF THE ENEA GRID

USEFUL FOR IMPROVING THE OVERALL NETWORK EFFICIENCY