Package org.jgroups.protocols
Class PERF
- java.lang.Object
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- org.jgroups.stack.Protocol
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- org.jgroups.protocols.PERF
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- All Implemented Interfaces:
Lifecycle
public class PERF extends Protocol
Protocol measuring latency between stacks. Ondown(org.jgroups.Message)
, a header is added to the message with the ID of the PERF protocol, and the start time is set in the header. Onup(org.jgroups.Message)
, the time difference is computed and a rolling average is updated in PERF.
Note that we can have several measurements by inserting PERF protocols with different IDs (Protocol.id) into the stack. If PERF is used to measure latency between nodes running on different physical boxes, it is important that the clocks are synchronized, or else latency cannot be computed correctly (and may even be negative).- Since:
- 3.5
- Author:
- Bela Ban
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Nested Class Summary
Nested Classes Modifier and Type Class Description protected static class
PERF.PerfHeader
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Field Summary
Fields Modifier and Type Field Description protected Average
avg
protected int
avg_size
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Fields inherited from class org.jgroups.stack.Protocol
after_creation_hook, down_prot, ergonomics, id, local_addr, log, policies, stack, stats, up_prot
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Constructor Summary
Constructors Constructor Description PERF()
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Method Summary
All Methods Instance Methods Concrete Methods Modifier and Type Method Description java.lang.Object
down(Message msg)
A message is sent down the stack.void
init()
Called after a protocol has been created and before the protocol is started.double
latencyInMs()
double
latencyInNs()
void
resetStats()
java.lang.Object
up(Message msg)
A single message was received.void
up(MessageBatch batch)
Sends up a multiple messages in aMessageBatch
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Methods inherited from class org.jgroups.stack.Protocol
accept, addPolicy, addr, addr, afterCreationHook, destroy, down, down, enableStats, getAddress, getComponents, getDownProtocol, getDownServices, getId, getIdsAbove, getLevel, getLog, getName, getPolicies, getProtocolStack, getSocketFactory, getThreadFactory, getTransport, getUpProtocol, getUpServices, getValue, isErgonomics, level, parse, policies, providedDownServices, providedUpServices, removePolicy, requiredDownServices, requiredUpServices, resetStatistics, setAddress, setDownProtocol, setErgonomics, setId, setLevel, setPolicies, setProtocolStack, setSocketFactory, setUpProtocol, setValue, start, statsEnabled, stop, toString, up
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Field Detail
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avg
protected Average avg
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avg_size
protected int avg_size
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Method Detail
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latencyInNs
public double latencyInNs()
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latencyInMs
public double latencyInMs()
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init
public void init() throws java.lang.Exception
Description copied from class:Protocol
Called after a protocol has been created and before the protocol is started. Attributes are already set. Other protocols are not yet connected and events cannot yet be sent.
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resetStats
public void resetStats()
- Overrides:
resetStats
in classProtocol
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down
public java.lang.Object down(Message msg)
Description copied from class:Protocol
A message is sent down the stack. Protocols may examine the message and do something (e.g. add a header) with it, before passing it down.
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up
public java.lang.Object up(Message msg)
Description copied from class:Protocol
A single message was received. Protocols may examine the message and do something (e.g. add a header) with it before passing it up.
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up
public void up(MessageBatch batch)
Description copied from class:Protocol
Sends up a multiple messages in aMessageBatch
. The sender of the batch is always the same, and so is the destination (null == multicast messages). Messages in a batch can be OOB messages, regular messages, or mixed messages, although the transport itself will create initial MessageBatches that contain only either OOB or regular messages. The default processing below sends messages up the stack individually, based on a matching criteria (callingProtocol.accept(Message)
), and - if true - callsProtocol.up(org.jgroups.Event)
for that message and removes the message. If the batch is not empty, it is passed up, or else it is dropped. Subclasses should check if there are any messages destined for them (e.g. usingMessageBatch.iterator(Predicate)
), then possibly remove and process them and finally pass the batch up to the next protocol. Protocols can also modify messages in place, e.g. ENCRYPT could decrypt all encrypted messages in the batch, not remove them, and pass the batch up when done.
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