midaemon(1)midaemon(1)NAMEmidaemon - HP-UX Performance Measurement Interface daemon.
SYNOPSISmidaemon [options]
HP-UX COMPATIBILITY
Origin: Measurement Interface daemon for Performance Management
tools, such as GlancePlus/UX and HP Performance Agent.
Version: HP-UX 11i v1 (11.11) and later
DESCRIPTION
This program provides the Measurement Interface layer between the ker‐
nel and the Performance Collectors. This program translates trace data
into Measurement Interface counter data using a memory based MI Perfor‐
mance Database to hold the counters. This database is accessed by col‐
lector programs such as glance, gpm, and scopeux.
The Measurement Interface daemon, midaemon, communicates with special
entry points in the kernel and must be executed as root. It is normally
started automatically by the collector programs themselves.
By default, the midaemon process runs with two independent threads to
optimize performance. It also locks itself in physical memory to avoid
paging. This helps avoid potential data loss on a busy system. It also
runs at a POSIX priority (-16) by default. The default values can be
modified by specific options in the command line.
The midaemon process uses a dynamic shared memory allocator for the
performance metrics database management. This offers flexibility in the
allocation of the performance data classes and in the enablement of the
kernel instrumentation. The midaemon process allocates the performance
database class entries as needed. You should not use Performance Class
specific midaemon options to limit the size of MI Performance Database.
Instead, if you encounter memory pressure and the virtual set size of
the midaemon is excessive, you can limit the virtual set size of the MI
shared memory database by using the -smdvss option. This is not recom‐
mended in normal operations. Contact your support representative for
assistance. The MI Performance Database is not locked in physical mem‐
ory, so only the MI Classes active memory pages are paged in.
The midaemon backgrounds itself when started. Status and errors are
written to the file: /var/opt/perf/status.mi.
COMMAND LINE OPTIONS
-? this option displays the mode dependent available options on
standard error.
-bufsets <value>
the midaemon process uses bufsets buffers to contain the ker‐
nel instrumentation data. This option changes the bufsets
default value. The default value is defined by experience and
validation tests. It is not recommended to change this value
unless the performance tools or the midaemon process itself
reports losing buffers. If the passed value is less than 2,
the value is reset to the default value for performance rea‐
sons. This option is only valid for a multithreaded midaemon.
DEFAULT: 4 sets.
-disks <value>
limits the maximum number of entries in the DISK Class of the
MI Performance Database.
DEFAULT: dynamic.
-goldenresource_off
turns off the resource metrics collection for transactions.
Normally collection of per-transaction resource metrics is
controlled in HP Performance Agent by parm file setting. This
midaemon option will override control from the parm file.
-goldenresource_on
turns on the resource metrics collection for transactions.
Normally collection of per-transaction resource metrics is
controlled in HP Performance Agent by parm file setting. This
midaemon option will override control from the parm file.
-kernel <system-file>
specifies the booted kernel system file to the Measurement
Interface. Can be used to run the performance tools on sys‐
tems which are not booted from the default /stand/vmunix ker‐
nel.
DEFAULT: /stand/vmunix.
-kths <value>
specifies the maximum number of entries THREAD Class of the
MI Performance Database. By default, the MI determines a max‐
imum number of entries based on the nproc kernel parameter.
DEFAULT: dynamic. MI Performance Database.
-lfs <value>
limits the maximum number of entries in the LOGICAL FILE SYS‐
TEM Class of the MI Performance Database.
DEFAULT: dynamic.
-mlock specifies the locking of the MI Shared Memory Performance
Database in memory. By default, MI does not lock its shared
memory segment and pages in only the active memory pages,
creating less intrusiveness on the system memory utilization.
DEFAULT: off.
-nfs <value>
limits the maximum number of entries in the NFS Class of the
MI Performance Database.
DEFAULT: dynamic.
-no_multithread
starts the midaemon process using a single thread of execu‐
tion. This causes the midaemon to revert back to the single-
threaded method used in previous releases for processing ker‐
nel traces.
DEFAULT: off.
-normal_prio
specifies that the midaemon process starts in the normal
scheduling priority.
DEFAULT: off
WARNING: This option must not be used if ARM instrumented
data is collected. If this option is used when ARM instru‐
mented data is collected, the transaction throughput handled
by midaemon is affected.
-p specifies that the midaemon process runs permanently, even if
no performance tools are attached to the Measurement Inter‐
face. Can be used to keep an midaemon running all the time a
system is booted when other command line options are being
used so that special settings will not be lost if the perfor‐
mance tools using the midaemon are restarted.
DEFAULT: off.
-pids <value>
specifies the maximum number of entries PROCESS Class of the
MI Performance Database. By default, the MI determines a max‐
imum number of entries based on the nproc kernel parameter.
DEFAULT: dynamic. MI Performance Database.
-posixprio <priority>
specifies POSIX realtime SCHED_FIFO priority to be used for
the midaemon process. The default value was chosen by experi‐
ence and tests with other system daemons. The value entered
must be in the range from 0 - 31 which the system remaps to a
negative number in the range of -1 to -32. This type of
scheduling is only used if the midaemon is multithreaded (no
-no_multithread option used).
DEFAULT: 15 (mapped to -16).
-rtprio <priority>
specifies the non-posix process real-time priority to be used
for the midaemon process. The default value was chosen by
experience and tests with other system daemons and should not
normally be modified. The cpu overhead of the midaemon is
relative to the amount of activity on the overall system and
reducing the midaemon priority may cause data loss. The
rtprio default is only used when the midaemon is running non-
multithreaded (the -no_multithread option used).
DEFAULT: 50.
-sizes specifies that the midaemon process writes the sizes of the
enabled Classes of the MI Shared Memory Performance Database
in the status.mi file.
DEFAULT: off.
-skipbuf specifies that the midaemon skip ahead a number of bufsets in
the case where the midaemon is unable to keep up with the
kernel instrumentation data. This option changes the skipbuf
default value. The default value is defined by experience and
validation tests. It is not recommended to change this value
unless the performance tools or the daemon process itself
report losing buffers. If the passed value is less than 0,
or greater then the number of bufsets, the value is reset to
the default value for performance reasons. This option is
only valid for multithreaded midaemon.
DEFAULT: 2 sets.
-smdvss <value>
specifies the maximum virtual set size of the MI Shared Mem‐
ory Performance Database. This option limits the amount of
memory used by the database and should be used to limit the
dynamic expansion of the performance Classes. The default
size is kernel dependent. The -sizes option can be used to
determine the MI Performance Database sizing values.
DEFAULT: kernel dependent.
-T specifies that the active midaemon process terminates immedi‐
ately without any regard to attached performance tools. This
option is for use only during software installation or
removal procedures as it will cause glance or scopeux to fail
if they are running.
DEFAULT: off.
-udts <value>
specifies the maximum number of entries UDT (ARM transaction
data) Class of the MI Performance Database.
MI ERROR MESSAGES
In case of errors, midaemon was designed to use well defined exit val‐
ues and to write explicit error messages in the /var/opt/perf/status.mi
file. The error messages are formatted:
- name of the running midaemon program - timestamp,
- name of the routine generating the error - error message,
- error message generated by a perror(3C) call if a system call has
failed. This information may be of use when reporting problems.
DEPENDENCIES
The midaemon is binary compatible between supported HP9000 systems. It
is a 32-bit binary format which will execute on both 32-bit and 64-bit
kernels.
EXAMPLES
The standard midaemon process execution is
% midaemon
To specify the MI Shared Memory Database size up to 2 Megabytes at the
MI initialization:
% midaemon-smdvss 2M
WARNINGS
The midaemon program is automatically executed by performance tools
such as GlancePlus (glance, gpm), or HP Performance Agent (scopeux).
However, it can be executed manually to customize the MI Performance
Database or to send to the active midaemon process specific requests.
If the creation of the status.mi file failed, midaemon will use the
error file /tmp/status.mi.
SEE ALSOglance(1), gpm(1), scopeux(1), mwa(1), ttd(1).
HP-UX midaemon(1)
