Apache Module mod_mpmstats

Description:	MPM/thread monitoring module for IBM HTTP Server
Status:	Extension
Module Identifier:	mpmstats_module
Source File:	mod_mpmstats.c

Summary

This module periodic information about IBM HTTP Server processing threads in the error log. Prior to V7R0, it was only available as part of the ihsdiag mustgather tool.

mpmstats: rdy 24 bsy 1 rd 0 wr 1 ka 0 log 0 dns 0 cls 0 ... module mod_test.c took 5000ms to return OK in phase handler ... mpmstats (long-running requests): bsy: 3 in mod_test.c

Topics

Limitations
Description of fields

Limitations

In 8.5.0.0 and later on z/OS, the displayed number of threads in keepalive state is always zero due to the Event MPM. This also means that if there are non non-keepalive connections, a report will not be written when the interval elapses.
Threads that are busy in non-module code cannot be counted with TrackModules

Description of fields

rdy: The number of idle threads
bsy: The number of total threads in any non-idle state
rd: The number of threads reading client requests. All states of processing before the "handler" takes control are in this state
wr: The number of threads in "write" state, which includes all Apache phases after a request has been read, including mapping to a file, access control, and the handler responsible for handling the response.
ka: threads in keepalive state
ka will always report as 0.
log: threads in logging state
dns: threads looking up a hostname
cls: threads in (lingering) close state

MPMStatsBusyThreshold Directive

Description:	Sets threshold for "approaching MaxClients..." notice
Syntax:	`MPMStatsBusyThreshold ratio`
Default:	`MPMStatsBusyThreshold 0.9`
Context:	server config
Status:	Extension
Module:	mod_mpmstats
Compatibility:	IHS 8.5.5.18 and later (PH24265)

By default, IHS periodically warns if 90% of the servers threads are busy. Use this directive to change the threshold by specifying a value between ".01" and "1.0".

MPMStatsSystemLog Directive

Description:	Copies "approacing MaxClients..." notice to z/OS system log
Syntax:	`MPMStatsSystemLog ON\|OFF`
Default:	`MPMStatsSystemLog OFF`
Context:	server config
Status:	Extension
Module:	mod_mpmstats
Compatibility:	IHS 8.5.5.18 and later on z/OS (PH24265)

This directive copies the "approaching MaxClients..." message to the z/OS system log. The message has the format as shown below

BPXM023I ($USERID) CRIHS0003I $JOBNAME mpmstats: approaching MaxClients ($THREADSUSED/$MAXCLIENTS)

ReportInterval Directive

Description:	Configures the interval for writing thread statistics
Syntax:	`ReportInterval #-of-seconds`
Default:	`0, but default configuration has ReportInterval 600`
Context:	server config
Status:	Extension
Module:	mod_mpmstats

Every ReportInterval number of seconds, this module reports thread statistics if the server is non-idle.

SlowThreshold Directive

Description:	Sets a trigger for modules exceeding a specific timeout
Syntax:	`SlowThreshold seconds \| millisecondsms`
Default:	`unset`
Context:	server config
Status:	Extension
Module:	mod_mpmstats

This directive causes requests or module invocations which take more than the specified timeout to generate two new messages:

When a module uses more than the threshold time in any phase of processing, an immediate ErrorLog entry of the form:
module mod_test.c took 5000ms to return OK in phase handler
If the threshold is exceeded by any request during a ReportInterval, that thread will be individually reported in this modules output in the form
mpmstats (long-running requests): bsy: 3 in mod_test.c

SMFReportInterval Directive

Description:	Enables SMF reporting of mpmstats data
Syntax:	`SMFReportInterval seconds`
Default:	`0`
Context:	server config
Status:	Extension
Module:	mod_mpmstats
Compatibility:	IHS 8.5.5 and later on z/OS only

If set to a non-zero value, IHS writes an SMF Type 103 Subtype 13 record with the following contents.

field	length
parent process ID	4
ready threads	4
busy threads	4
reading threads	4
writing threads	4
logging threads	4
dns threads	4
closing threads	4
keepalive threads	4
bytes served	8
requests served	8
servername len	4
servername	$servername_len

Keepalive note

Currently the KeepAlive threads is always zero on z/OS using the Event MPM.

TrackHooks Directive

Description:	Enables reporting of time spent in individual Apache phases
Syntax:	`TrackHooks allhooks \| post_read_request \| check_userid \| check_user_access \| auth_checker \| handler`
Default:	`unset`
Context:	server config
Status:	Extension
Module:	mod_mpmstats

This directive allows the time spent in each Apache phase to be recorded in an environment variable. Original documentation on this feature

post_read_request: %{TPR}e
check_userid: %{TCU}e
check_user_access: %{TCA}e
auth_checker: %{TAC}e
handler: %{TRH}e
allhooks: macro setting to enable all hooks

TrackHooksOptions Directive

Description:	Enables more detailed tracking of hooks
Syntax:	`TrackHooksOptions millis\|permodule\|logslow\|notice\|allopts`
Default:	`unset`
Context:	server config
Status:	Extension
Module:	mod_mpmstats

This directive allows the time spent in each Apache phase to be recorded in an environment variable. Original documentation on this feature

millis: %{Txx}e variables will be recorded in millseconds
permodule: For phases where multiple modules participate, record the time each separate module takes to run
logslow: If specified, causes messages like "module mod_test.c took 5000ms to return OK in phase handler" when SlowThreshold is exceeded. Without the "notice" option below, the message is logged at INFO level.
notice: If logslow condition occurs, log at NOTICE level instead of INFO
allopts: macro setting to enable all options

TrackModules Directive

Description:	Enables reporting of individual modules busy on a thread
Syntax:	`TrackModules ON\|OFF`
Default:	`ON`
Context:	server config
Status:	Extension
Module:	mod_mpmstats

This directive, which depends on ExtendedStatus, enables reporting of which Apache modules are executing on active threads.

mpmstats: bsy: 1 in mod_was_ap22_http.c