Transition to a new CPU benchmark

on behalf of the “GDB benchmarking WG”:

HEPIX: Manfred Alef, Helge Meinhard, Michelle Michelotto

Experiments: Peter Hristov, Alessandro De Salvo and Franco Brasolin, Marie-Christine Sawley, Hubert Degaudenzi

Chair: Gonzalo Merino

2

Background

• July 2008: The HEPIX CPU WG recommended the MB to adopt SPECall_cpp2006 as new benchmark. – Document describing the new benchmark chosen and the

conditions in which it will have to be run is in preparation by the HEPIX WG.

• Mandate of our Working Group:– Publish the recipe for running the benchmark (see above)– Agree on conversion factors to convert experiment requirement

and site pledges tables from si2k units to the new units

• Aim of this talk is not to present a formal proposal, but to report on the Group discussions up to now and get reactions/feedback.

3

LXBENCH cluster at CERN

• Cluster with 8 reference machines for benchmarking at CERN: – lxbench01, lxbench02, … lxbench08 – (see https://twiki.cern.ch/twiki/bin/view/FIOgroup/TsiLxbench)

• Old (SPECint2000) and new (SPECall_cpp2006) benchmarks have been run in every machine.

• Experiments also ran their apps in every machine (May-08, HEPIX CPU WG)– Conclusion: All 4 experiments see good correlation between

their applications and both benchmarks.– NOTE: Not all the experiments ran in lxbench08

• Only ATLAS managed to run and provide results for lxbench08

• LHCb says it did run, but results still not provided to the HEPIX group

• CMS and ALICE did not manage to run in lxbench08 in May

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SPECs on LXBENCH

SPECall_cpp2006 (new)

KSI2K-LCG (old)

Ratio new/old

Intel Xeon 2.8 GHz lxbench01 10,24 2,25 4,55

Intel Xeon 2.8 GHz lxbench02 9,63 2,24 4,29

AMD Opteron 275 lxbench03 28,03 6,20 4,52

Intel Xeon 5150 lxbench04 35,58 8,51 4,18

Intel Xeon 5160 lxbench05 38,21 9,27 4,12

AMD Opteron 2218 lxbench06 31,67 6,85 4,62

Intel Xeon E5345 lxbench07 57,52 14,19 4,05

Intel Xeon E5410 lxbench08 60,76 15,83 3,84

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Current processors at the T0/T1s

Result of a poll the Tier-0 and Tier-1s showing a snapshot of the number of cores currently installed of each processor type

0

2000

4000

6000

8000

10000

12000

14000

16000

18000

20000

AMD O

pter

on 24

6 2.0

GHz

AMD O

pter

on 24

8 2.2

GHz

AMD O

pter

on 26

5 1.8

GHz

AMD O

pter

on 27

0 2.0

GHz

AMD O

pter

on 27

5 2.2

GHz

AMD O

pter

on 23

50 2

.0 G

Hz

AMD O

pter

on 23

54 2

.2 G

Hz

AMD O

pter

on 82

22 3

.0 G

Hz

Inte

l P4

2.80

GHz

Inte

l Xeo

n 2.80

GHz

Inte

l Xeo

n 3.20

GHz

Inte

l Xeo

n 3.4

GHz

Inte

l Xeo

n E51

30 2

.00

GHz

Inte

l Xeo

n 514

8 2.

33 G

Hz

Inte

l Xeo

n 515

0 2

.66

GHz

Inte

l Xeo

n 516

0 3.

00 G

Hz

Inte

l Xeo

n E53

45 2

.33

GHz

Inte

l Xeo

n E53

35 2

.0 G

Hz

Inte

l Xeo

n X53

55 2

.66

GHz

Inte

l Xeo

n E54

10 2

.33

GHz

Inte

l Xeo

n E54

20 2

.50

GHz

Inte

l Xeo

n E54

30 2

.66

GHz

Inte

l Xeo

n E54

40 2

.83

GHz

Inte

l Xeo

n E54

50 3

.00

GHz

Inte

l Xeo

n L54

20 2.

50 G

Hz

N c

ore

s

Xeon E5345(Quad-core)

Xeon E5430(Quad-core)

AMD Intel

Dual-Core Quad-Core

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Transition to a new CPU unit

• The most representative platform, providing the majority of capacity at T0/T1s today are the Intel QuadCore processors.

• Propose to focus on the conversion factor results got at the newest (Intel QuadCore) machines: lxbench07 and lxbench08– lxbench07: 4,05– lxbench08: 3,84

• Manfred Alef did the exercise of computing the CPU performance delivered by the whole GridKa farm with both the old and the new SPEC benchmarks– large site with quite a lot of different processors realistic

“mixture”– Result: new/old conversion factor = 4,19

• Precision O(5%) intrinsic to these measurements: not significative.

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Transition to a new CPU unit

• Proposal: Take a simple approach and adopt 4,00 as conversion factor. – Give more importance to having a simple rule for the transition

period than discussing about decimals within the 5% precision.– Caveat: during the next days, ALICE and CMS will complete

their benchmarking runs up to lxbench08 to confirm the good correlation (no surprises expected).

• Transition period: before end April (Spring C-RRB meeting)– Experiments will re-compute requirements tables given the new

LHC schedule: new numbers should be computed already with the new unit.

– Sites should buy SPECcpu2006 and calibrate their farms to report their current CPU power in the new unit. Pledges for the Spring CRRB should be expressed in the new unit.