Workpackage 2 Proposal for an Extension of ASL

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Workpackage 2Proposal for an Extension of ASL

• T. Fahringer, M. Gerndt, J. Nabrzyskin, B.
  Parady, O. Plata, D. Tessera
• Based on work done at WP2 Poznan meeting in
  April.

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Outline

• Extension of ASL
• Property Templates
• Meta-properties
• Future Work

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Apart Specification Language (ASL)

• ASL supports description of
• performance related data
• performance properties.
• Several drawbacks of ASL
• Many properties are similar, yet must be
  specified separately. ? introduce property
  templates
• New properties cannot easily be described by
  existing ones. ? introduce meta-properties

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Property Templates

• Many performance properties differ only in
  accessed performance data.
• E.g. communication, I/O, and synchronization
  costs.

Property communication_costs (MPIRegion r,
Experiment e, Region rank_basis) LET float
cost summary(r,e).sums.comm_time IN CONDITION
cost gt 0 CONFIDENCE 1 SEVERITY
cost/duration(rank_basis,e)
Property io_costs (MPIRegion r, Experiment e,
Region rank_basis) LET float cost
summary(r,e).sums.io_time IN CONDITION cost gt
0 CONFIDENCE 1 SEVERITY cost/duration(rank_b
asis,e)
Property templates could be used for a generic
description of similar performance properties
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Property Templates (cont.)
PROPERTY TEMPLATE cost ltfloat cost_func(RegionSumm
ary)gt (Region r,
Experiment e, Region RankBasis)
LET costcost_func(summary(r,e)) IN CONDITION
cost gt 0 CONFIDENCE 1 SEVERITY
cost/duration(RankBasis,e)
float io_cost_func(RegionSummary
rs)rs.sums.io_time float sync_cost_func(RegionSu
mmary rs)rs.sums.sync_time float
comm_cost_func(RegionSummary rs)rs.sums.comm_time

Define new properties based on template by using
a defined function as template parameter.
PROPERTY costltio_cost_funcgt io_cost PROPERTY
costltsync_cost_funcgt sync_cost PROPERTY
costltcomm_cost_funcgt comm_cost
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Meta-properties (1)

• Meta-properties can be used to define new
  performance properties based on existing ones.
• Meta-properties are again defined as property
  templates.
• Meta-property parameters can be
• functions with defined signature
• performance properties with defined context
  signature

PROPERTY TEMPLATE property_on_all_processes
ltPROPERTY x(Region,Experiment,Process,Region)gt
(Region r, Experiment e, Region RankBasis)
CONDITION Forall p IN e.processors SUCH THAT
condition(x(r,e,p,RankBasis)) AND
confidence(x(r,e,p,RankBasis))1 CONFIDENCE
1 SEVERITY max(severity(x(r,e,p,RankBasis))
WHERE p in e.processes)

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Meta-properties (2)
PROPERTY TEMPLATE cost_per_process
ltFLOAT cost_func(RegionSummary)gt (Region r,
Experiment e, Process p, Region RankBasis)
LET cost cost_func(summary(r,e,p)) IN CONDIT
ION cost gt 0 CONFIDENCE 1 SEVERITY
cost/duration(RankBasis,e)
Float io_cost_func(RegionSummary
rs)rs.sums.io_time Float sync_cost_func(RegionSu
mmary rs)rs.sums.sync_time Float
comm_cost_func(RegionSummary rs)rs.sums.comm_time

PROPERTY cost_per_processltio_cost_funcgt
io_cost_per_process PROPERTY cost_per_processltsyn
c_cost_funcgt sync_cost_per_process PROPERTY
cost_per_processltcomm_cost_funcgt
comm_cost_per_process
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Meta-properties (3)

• PROPERTY TEMPLATE property_on_all_processes
• ltPROPERTY x(Region,Experiment,Process,Region)gt
• (Region r, Experiment e, Region RankBasis)
• CONDITION Forall p IN e.processors SUCH THAT
• condition(x(r,e,p,RankBasis)) AND
  confidence(x(r,e,p,RankBasis))1
• CONFIDENCE 1
• SEVERITY max(severity(x(r,e,p,RankBasis)) WHERE
  p in e.processes)

PROPERTY property_on_all_processes
ltio_cost_per_processgt io_cost PROPERTY
property_on_all_processes ltsync_cost_per_processgt
sync_cost PROPERTY property_on_all_processes
ltcomm_cost_per_processgt comm_cost
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Future Work

• Extend ASL Syntax for meta-properties and
  templates
• Case-studies of ASL for
• a few machines (e.g. Cray T3E)
• Case studies for OpenMP
• Formalize search for bottlenecks based on ASL.

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CASE-Studies

• WP2
• Specify properties for Cray T3E
• Specification of search process for properties
• WP3
• Experiment planing
• Effect of multiple sources of performance data.
• Set of test kernels/applications