Apache Module mod_arm4

ArmApplicationName Directive

Description:	Sets the name of the application registered with the ARM4 agent
Syntax:	ArmApplicationName string
Default:	ArmApplicationName "Apache HTTP Server"
Context:	server config
Override:
Status:	Base
Module:	mod_arm4

The directive is used to control the name of the application as registered with the ARM4 agent.

ArmInstrumentHandler Directive

Description:	Enables the arm_block/arm_unlock calls to be made across invocations of module handlers.
Syntax:	ArmInstrumentHandler "on|off"
Default:	ArmInstrumentHandler off
Context:	server config
Override:
Status:	Base
Module:	mod_arm4

The ARM4 standard defines agent functions, arm_block() and arm_unblock() that can be called to record when a process is about to perform an 'out-of-process' operation (e.g., network i/o) and to record when that 'out-of-process' operation completes. Ideally, Apache HTTP Server handlers that go "out-of-process" would be instrumented to make use of the optional callbacks defined by mod_arm4, arm_ap_block_transaction() and arm_ap_unblock_transaction to record "out-of-process" events with the ARM4 agent.

Setting "ArmInstrumentHandler on" causes this module to call arm_block() and arm_unblock on behalf of a handler that is not instrumented. There are a couple of problems with using this directive as implemented. First, mod_arm4 has no knowledge if a handler really goes "out-of-process". Second, the arm_block() is called in the fixups hook and the arm_unblock is called in the logging hook, so it is relatively coarse grained. A lot of "in-process" cycles can be consumed between these two hooks which would be incorrectly attributed to the "out-of-process" activity.

ArmLoadLibrary Directive

Description:	Sets the path to the ARM4 agent shared library.
Syntax:	ArmLoadLibrary file-path
Default:	ArmLoadLibrary libarm4 (.dll on windows, .a on AIX, .so everywhere else)
Context:	server config
Override:
Status:	Base
Module:	mod_arm4

The ArmLoadLibrary can be used to configure mod_arm4 to use a specific ARM4 agent library. File-path is the path to the ARM4 agent library. q: abs or relative path?

ArmTransactionName Directive

Description:	Sets the transaction name registered with the ARM agent
Syntax:	ArmTransactionName string
Default:	ArmTransactionName "HTTP Request"
Context:	server config
Override:
Status:	Base
Module:	mod_arm4

The ArmTransactionName directive sets the name of the transaction registered to the ARM agent. (need more...)