Transcript Events Hierarchy Author: Anna Bekkerman [email protected] Events Are Everywhere Node Client Server Target system Data Events LMM Node LMM Node Client LMM Basic Types  Messaging events – –  Application events –  Occur when data is being read from/written to communication channels.

Events Hierarchy
Author: Anna Bekkerman
[email protected]
Events Are Everywhere
Node
Client
Server
Target system
Data
Events
LMM
Node
LMM
Node
Client
LMM
Basic Types
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Messaging events
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Application events
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Occur when data is being read from/written to
communication channels used in the DCAS
system
Can be matched to form messages
Generated by DCAS applications
Metrics
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Measurements of resource utilization
Messaging Events’ Characteristics
Type
Communication
Channel
How They Are
Obtained
LDM
LDM product
queue
WDSS
WDSS-II linear
buffer
Socket
TCP connection
Wrappers for
LDM function
calls
Wrappers for
WDSS-II function
calls
RAPIDS API
calls
LDM Events
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Each event has a number of properties
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Type: pq_insert or pq_remove
Feed type: class of a data product coming from a common
source
Sequence number associated with the data product
Product size: number of bytes in data section of the product
Product ID: usually a string describing a product
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For example: “Reflectivity_20070603_0112.netcdf.gz”
Two LDM events are matched if their types are
different and the rest of the properties are equal
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Source: pq_insert
Destination: pq_remove
WDSS Events
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Each event has a number of properties
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Type: lb_read or lb_write
Linear buffer ID: a number associated with the linear buffer
Message length
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Linear buffers contain messages describing which
products/meteorological features have been processed
Message: a string describing a product/feature
Two WDSS events are matched if their types are
different and messages are equal
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Source: lb_write
Destination: lb_read
Socket Events
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Each event has a number of properties
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Type: socket_write or socket_read
Sender address and port
Receiver address and port
Sequence number associated with the message
Message length
Message
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For example: “control”, “features”
Two socket events are matched if their types are different and
the rest of the properties are equal
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Source: socket_write
Destination: socket_read
Application Events
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Must be explicitly generated using RAPIDS
API calls
Need not be matched
Types:
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Error
Variable
Algorithm
Debug
Error events
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Generated when an error occurs
Have three significance levels
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Warning, Severe and Fatal
On the message diagram are depicted with
cross ( )
Variable events
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Generated to report the current value of a
variable
On the message diagram are depicted with
five pointed star ( )
Algorithm events
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Have a type associated with them: start
and end
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Generated to report beginning/ending of
some action
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Algorithm, procedure, cycle etc.
On the message diagram are depicted with:
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Start: small arrow pointing up ( )
End: small arrow pointing down ( )
Dedug events
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Generated to report debug messages
On the message diagram are depicted with
vertical bar ( )
Common Properties
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Each messaging and application event has the
following properties:
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
Timestamp
PID and name of the process which generated the event
ID of the node where the event came from
Detailed information about events can be obtained:
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From log files
From the message diagram if RAPIDS visualization client is
employed to view the events
Obtaining Process Name
signatures
Events know names of the processes which generated them
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The name of a process might be very long!
Solution: generate a signature for the process name
and send it along with the events
When RAPIDS server receives an event it compares
its process signature with signatures of monitored
processes provided in the configuration file
Drawback: if a process has not been mentioned in
the configuration file, its events will be ignored
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Even ownerless events are logged!
Metrics
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Each metric has a key and value
Process metrics also have a PIDs
Often a group of metrics must be used to
calculate utilization of a resource
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For example: to calculate utilization of the
memory the following metrics are needed
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The amount of free and used physical memory
The amount of free and used swap memory
Implementation of Events Hierarchy
event
byte[] toBytes()
int nodeID;
Date occurredAt;
String processName;
int mark;
<<interface>>
Loggable
int key;
Object value;
Event
DiagramEvent
Metric
boolean correspondTo(Event
e)
events
ApplicationEvent
MessagingEvent
ProcessMetric
LDMEvent
TCPEvent
WDSSEvent
ErrorEvent
VariableEvent
DebugEvent
AlgorithmEvent