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Programming Interface Information:
The Monitor Records are intended Programming Interfaces that allow the customer to write programs to obtain services of z/VM. |
MRSEKSEK
PrologControl Block Contents
Cross Reference
MRSEKSEK Prolog
DSECT NAME - SEKSEK
FUNCTION - Map a Monitor record.
LOCATED By -
Through the Monitor Control Area
REFERENCED CONTROL BLOCKS -
MRRECHDR Monitor Record Header
NAME - MRSEKSEK
DESCRIPTIVE NAME - Monitor Event Record
Domain 7 - Seek Domain
Record 1 - Seek Data
DESCRIPTION - Record of access arm movement ("Seek I/O") on a DASD
device or of a set paging parameter to a cache device.
Generated each time an I/O channel program containing
seek commands(s) is executed.
This record contains seek data that may enable a
user, such as an operating system developer, to tune
DASD seek scheduling algorithms. This record is NOT
intended for DASD load balancing. However, it can be
used to tune a cached minidisk to minimize the number
of tracks that must be cached.
NOTES:
-- Because of the frequency of seek I/O operations, an extremely
large number of this record will be generated. For this
reason, seek-domain monitoring should be limited to specific
devices or a specific set of devices.
-- The order in which the records are generated may not be the
order in which the commands are executed by the device.
-- The seek may not be executed by a device when there is a
permanent device error or when branching is done in the channel
program which bypasses segments.
MRSEKSEK Control Block Contents
Offsets
Dec Hex Type Len Name (Dim) Description
0 0 Structure 84 SEKSEK Start of monitor record
0 0 Character 0 SEKSEK_MRHDR Record header. See MRRECHDR
for details.
0 0 Character 20 MRHDR
0 0 Unsigned 2 MRHDRLEN record length in bytes
2 2 Unsigned 2 MRHDRZER field of zeros
4 4 Unsigned 1 MRHDRDM domain identifier
5 5 Unsigned 1 *
6 6 Unsigned 2 MRHDRRC record identifier
8 8 Character 8 MRHDRTOD Time at which this record was
built. In time-of-day (TOD)
clock format. See IBM System
370 XA Principle of Operation
for explanation of format.
16 10 Character 4 *
20 14 Character 0 MRHDR_END End of header
20 14 Unsigned 4 SEKSEK_RDEVSID Host subchannel I.D. number
defined at initialization
24 18 Unsigned 2 SEKSEK_CALCURCY Last seek cylinder for
previous DASD channel program
executed. RDEVCYL
SEKSEK_CALCURCY is deprecated
and should not be used for
further development. Code
should be changed to use
SEKSEK_CALCURCY32 defined
below. For values above 'FFFF'x
then this field will contain
'FFFF'x (and will not wrap).
26 1A Unsigned 2 SEKSEK_CALSKCYL First cylinder requested in
seek command(s) in this real
channel program. IORCYL
SEKSEK_CALSKCYL is deprecated
and should not be used for
further development. Code
should be changed to use
SEKSEK_CALSKCYL32 defined
below. For values above 'FFFF'x
then this field will contain
'FFFF'x (and will not wrap).
28 1C Unsigned 2 SEKSEK_CALSKHD First head number requested
in seek command(s) in this real
channel program. IORHEAD
30 1E Bitstring 1 SEKSEK_CALFLAGS Flag byte
1... .... SEKSEK_IORDWRIT ON=This is a WRITE channel
program. OFF=This is a READ
channel program.
.1.. .... *
..1. .... *
...1 .... *
.... 1... *
.... .1.. *
.... ..1. *
.... ...1 *
31 1F Bitstring 1 * Reserved for IBM use
32 20 Character 8 SEKSEK_VMDUSER Userid of requestor of seek
command(s) in this real channel
program. If 'SYSTEM', CP is the
requestor.
40 28 Unsigned 4 SEKSEK_IORPOSCT Number of DASD access arm
position changes within this
real channel program.
44 2C Unsigned 4 SEKSEK_IORPOSSM Amount of access arm
movements (displacements).
Cumulative total of absolute
differences, in cylinders,
between successive seek
operation within this real
channel program. SEKSEK_IORPOSSM
is deprecated and should not be
used for further development.
Code should be changed to use
SEKSEK_IOSPOSSM64 defined
below. For values above
'FFFFFFFF'x then this field
will contain 'FFFFFFFF'x (and
will not wrap).
48 30 Unsigned 2 SEKSEK_CALECYL Final cylinder number
(position after this real
channel program completes).
IORECYL. SEKSEK_CALECYL is
deprecated and should not be
used for further development.
Code should be changed to use
SEKSEK_CALECYL32 defined below.
For values above 'FFFF'x then
this field will contain 'FFFF'x
(and will not wrap).
50 32 Unsigned 2 SEKSEK_VDEVDEV Virtual device number of the
target device. Not applicable
if CP is the requestor (i.e.,
SEKSEK_VMDUSER = 'SYSTEM').
52 34 Character 8 SEKSEK_CALUSER Userid of the owner of the
target device. Not applicable
if CP is the requestor (i.e.,
SEKSEK_VMDUSER = 'SYSTEM').
60 3C Unsigned 2 SEKSEK_RDEVDEV Device number
62 3E Unsigned 2 * Reserved and available for
IBM use.
64 40 Unsigned 4 SEKSEK_CALCURCY32 Last seek cylinder for
previous DASD channel program
executed. RDEVCYL
68 44 Unsigned 4 SEKSEK_CALSKCYL32 First cylinder requested in
seek command(s) in this real
channel program. IORCYL
72 48 Character 8 SEKSEK_IORPOSSM64
72 48 Unsigned 4 SEKSEK_IORPOSSM64_HI
76 4C Unsigned 4 SEKSEK_IORPOSSM64_LO Amount of access arm
movements (displacements).
Cumulative total of absolute
differences, in cylinders,
between successive seek
operation within this real
channel program.
80 50 Unsigned 4 SEKSEK_CALECYL32 Final cylinder number
(position after this real
channel program completes).
IORECYL
84 54 Character 0 SEKSEK_END
MRSEKSEK Cross Reference
Hex Hex
Name Offset Length Value
MRHDR 0 20
MRHDR_END 14 0
MRHDRDM 4 1
MRHDRLEN 0 2
MRHDRRC 6 2
MRHDRTOD 8 8
MRHDRZER 2 2
SEKSEK 0 84
SEKSEK_CALCURCY 18 2
SEKSEK_CALCURCY32 40 4
SEKSEK_CALECYL 30 2
SEKSEK_CALECYL32 50 4
SEKSEK_CALFLAGS 1E 1
SEKSEK_CALSKCYL 1A 2
SEKSEK_CALSKCYL32 44 4
SEKSEK_CALSKHD 1C 2
SEKSEK_CALUSER 54 8
SEKSEK_END 40 0
SEKSEK_IORDWRIT 1E 80
SEKSEK_IORPOSCT 28 4
SEKSEK_IORPOSSM 2C 4
SEKSEK_IORPOSSM64 48 8
SEKSEK_IORPOSSM64_HI 48 4
SEKSEK_IORPOSSM64_LO 4C 4
SEKSEK_MRHDR 0 0
SEKSEK_RDEVDEV 3C 2
SEKSEK_RDEVSID 14 4
SEKSEK_VDEVDEV 32 2
SEKSEK_VMDUSER 20 8
This information is
based on z/VM V6R1.0.
Last updated on 31 Dec 2009 at 14:50:13.
Copyright IBM Corporation, 1990, 2009