IOPool/Input/doc/IOExerciser-README - master - githubmirror/cmssw

IOPool/Input/doc/IOExerciser-README
54 строки2 KB
Brian Bockelman
Correct documentation example.
16 авг 2013, 17:36
16 авг 2013, 17:36c008e0b

This module is designed to help benchmark CMSSW I/O performance.

The IOExerciser EDAnalyzer reads a fixed percentage of branches from a
file (percentages are done by the size of the branch) and, at a fixed interval,
will read out all the data in an event.

To emulate production work, set the percent read to 100%.  To emulate analysis
jobs, set the percent read to around 30% and the trigger factor to 10-100
(there's a wide range of analysis behavior).

To emulate a traditionally problematic I/O job, set the percent read to 10% and
the trigger factor to 10-20.

The selection strategy determines how branches are selected - smallest first,
largest first, or round robin:
- 'smallestFirst' (default): Read branches in increasing order of size until limit is hit.
- 'largestFirst': Read branches in decreasing order of size until limit is hit.
- 'roundRobin':   Read a small branch, then large branch.  Repeat until size limit is hit.

Smallest-first will allow you to stay closest to the desired percent read.
Round robin is likely closer to user behavior.

Run "edmPluginHelp -p IOExerciser" for online help.


********************************
Here's an example configuration:

import FWCore.ParameterSet.Config as cms

process = cms.Process("Demo")

process.load("FWCore.MessageService.MessageLogger_cfi")
process.MessageLogger.cerr.FwkReport.reportEvery = 100
# Uncomment the following lines for thorough debugging info
#process.MessageLogger.debugModules.append("IOExerciser")
#process.MessageLogger.cerr.threshold = 'INFO'
#process.MessageLogger.cerr.INFO.limit = 500

process.maxEvents = cms.untracked.PSet( input = cms.untracked.int32(-1) )

process.source = cms.Source("PoolSource",
    # replace 'myfile.root' with the source file you want to use
    fileNames = cms.untracked.vstring(
        '/store/mc/HC/GenericTTbar/GEN-SIM-RECO/CMSSW_5_3_1_START53_V5-v1/0010/A2B8D47D-BCAD-E111-B16A-BCAEC53296FB.root'
    )
)

process.out = cms.OutputModule('IOExerciser',
    percentBranches = cms.untracked.uint32(30),
    triggerFactor = cms.untracked.uint32(20),
)

process.outpath = cms.EndPath(process.out)