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I/O Component Analysis produces a report that allows you to
apply the methodology discussed in Section 2.4.4.2, Technique
Tutorial, to analyze the individual device response time
characteristics of your system.
MVS/XA AND MVS/ESA I/O COMPONENT ANALYSIS REPORT
A sample of the I/O Component Analysis report for MVS/XA and
MVS/ESA is shown in Figure 2-96. All time measurements for
the components of I/O in the report are in milliseconds. The
following information is shown in the figure:
INTERVAL The time and date of the first HARDVA File
START: observation included in the analysis.
INTERVAL The time and date of the last HARDVA File
END: observation included in the analysis.
DURATION: The total number of hours summarized by report,
rounded up to the nearest hour.
SYSID: The system identifier.
DEV NO.: The device number, CA MICS data element DEVADDR.
VOLSER: The volume serial number of the volume mounted
on the device.
DEVICE The device type as carried by the CA MICS
TYPE: DEVTYPE data element.
SSCH RATE: The number of start subchannels commands per
second (SSCH) issued to the device by the
system.
% BUSY: The percent device active (DVAPCACT) as measured
by RMF.
RESP: The estimated average response time. This value
is calculated as the sum of average queueing
delay, pending time, disconnect time, connect
time as described below.
QUEUE: The estimated average internal queuing delay
before IOS is able to start an I/O to the
device. This value is derived from
(DVAQUE/SAMPLES) / (DVASSC/DURATION) * 1000.
This can be viewed as the measured probability
of the device being queued multiplied by the
average length of time between I/O events.
PEND: The measured average pending time for the device
computed from data elements (DVAPEN/DVAMEC)
* 1000. This value is measured by the hardware
in an MVS/XA or MVS/ESA environment.
DISC: The measured average disconnect time for the
device computed from data elements
(DVADIS/DVAMEC) * 1000. This value includes
seek, latency, and RPS miss delays. It is
measured by the hardware in an MVS/XA or MVS/ESA
environment.
CONN: The measured average device I/O connect time
computed from data elements (DVACNN/DVAMEC)
* 1000. This value includes CCW fetch and data
transfer. It is measured by the hardware in an
MVS/XA or MVS/ESA environment.
ESCON: The measured average time that a device was
delayed due to ES connection (ESCON) director
port busy, computed from data elements
(DVADPBTM/DVAMEC) * 1000. This value is
measured by the hardware in an MVS/ESA
environment with Enterprise System connection
directors present.
To assist in the interpretation of the components of I/O, the
values of the I/O component times are plotted over a range of
55 milliseconds. This plot is presented on the right-hand
side of the report. The characters used to denote the I/O
components are:
Q - The internal queuing delay time for the device.
P - The pending delay time for the device.
D - The device disconnect time. This value includes
seek, latency, and RPS miss delays.
C - Connect time. This value includes CCW fetch and data
transfer.
Each character represents one millisecond. The calculated
values are rounded up by adding 0.49 milliseconds to the
calculated values. Values exceeding 55 milliseconds are
represented by a plus sign at the extreme right hand of the
plot.
CA MICS Performance Manager DASD I/O RESPONSE TIME COMPONENT ANALYSIS INTERVAL START: 06JUNyy:08:59 INTERVAL END : 06JUNyy:10:59 DURATION : 2:00:00 SYSID : SYSA -------------RESPONSE TIME COMPONENTS (MS)------------- DEV DEVICE SSCH % ------------AVERAGE TIME (MS)------------ . 1 . 2 . 3 . 4 . 5 . NO. VOLSER TYPE RATE BUSY RESP QUEUE PEND DISC CONN ESCON 1234567890123456789012345678901234567890123456789012345 ---- ------ -------- ----- ----- ------ ------ ------ ------ ------ ------ ------------------------------------------------------- 140 WORK41 3390 5.9 9.8 20.1 1.7 1.7 13.8 2.8 0.0 QQPPDDDDDDDDDDDDDDCCC 142 PAG403 3390 4.4 12.7 28.9 0.0 2.4 15.1 11.5 2.2 PPDDDDDDDDDDDDDDDCCCCCCCCCCC 143 AAA902 3390 2.1 4.1 20.6 0.5 0.8 14.5 4.9 0.0 PDDDDDDDDDDDDDDCCCCC 145 SPOOL1 3390 6.2 11.6 23.2 4.4 0.1 16.2 2.5 0.0 QQQQDDDDDDDDDDDDDDDDCC 147 AAA904 3390 1.4 3.1 22.4 0.8 0.2 14.6 6.8 0.0 QDDDDDDDDDDDDDDDCCCCCCC 148 SPAR05 3390 2.5 3.9 17.5 0.1 1.8 13.0 2.6 0.0 PPDDDDDDDDDDDDDCCC 14C AAA917 3390 1.1 2.2 21.9 0.4 0.3 16.5 4.7 0.0 DDDDDDDDDDDDDDDDCCCCC 240 VIPL01 3380J 3.1 7.6 26.8 2.0 0.4 17.2 7.3 0.0 QQDDDDDDDDDDDDDDDDDCCCCCCC 241 AAA909 3380J 1.3 2.2 17.7 0.2 1.1 13.1 3.3 0.4 PDDDDDDDDDDDDDCCC 242 PAG401 3380J 3.8 15.1 40.4 0.0 0.3 27.6 12.5 0.0 DDDDDDDDDDDDDDDDDDDDDDDDDDDDCCCCCCCCCCCC 246 AAA923 3380J 6.7 10.9 17.0 0.4 0.2 10.0 6.4 0.0 DDDDDDDDDDCCCCCC 24B AAA914 3380K 2.9 6.0 21.5 0.6 0.4 16.6 4.0 0.0 QDDDDDDDDDDDDDDDDDCCCC 24C AAA916 3380K 1.6 3.2 21.2 0.4 0.5 13.6 6.7 0.0 DDDDDDDDDDDDDDCCCCCCC 250 PAG404 3380K 4.1 14.8 36.2 0.0 2.6 22.0 11.6 2.3 PPPDDDDDDDDDDDDDDDDDDDDDDCCCCCCCCCCCC 252 WORK44 3380K 5.1 11.7 24.9 1.6 1.6 14.3 7.4 1.2 QQPPDDDDDDDDDDDDDDCCCCCCC 255 WORK45 3380K 8.0 22.0 32.8 4.5 0.8 17.3 10.2 0.0 QQQQPDDDDDDDDDDDDDDDDDCCCCCCCCCC 25A PAG405 3380K 2.1 4.1 21.5 0.9 0.7 17.4 2.4 0.0 QPDDDDDDDDDDDDDDDDDCC 25B WORK46 3380K 2.4 6.1 28.4 1.5 1.8 14.8 10.3 0.0 QPPDDDDDDDDDDDDDDDCCCCCCCCCC 25D PAG406 3380K 2.1 13.2 65.0 0.0 0.8 55.6 8.6 0.0 PDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDDD+ 25E WORK47 3380K 3.6 7.9 22.7 0.2 0.7 12.7 9.2 0.0 PDDDDDDDDDDDDDCCCCCCCCC 25F WORK48 3380K 2.2 6.4 32.5 2.0 1.2 15.9 13.4 0.0 QQPDDDDDDDDDDDDDDDDCCCCCCCCCCCCC
Figure 2-96. I/O Response Time Component Analysis Report for MVS/XA
MVS/370 I/O COMPONENT ANALYSIS REPORT
A sample of the I/O Component Analysis Report for an MVS/370
system is provided in Figure 2-97. All time measurements for
the components of I/O in the report are in milliseconds. The
information in the MVS/370 report that is measured or
calculated differently from the information on the MVS/XA and
MVS/ESA report is listed below:
DEV ADR: The device address in data element DEVADDR.
SIO RATE: The number of start I/Os per second (SIOs)
issued to the device by the system. Note that
the program excludes devices that have an SIO
rate of less than one per second, because the
equations that approximate the I/O time
components are poorly behaved for lightly loaded
devices.
RESP: The estimated average response time. This value
is calculated from the device utilization,
average queue length, and start I/O rate. The
values are data elements DVAPCACT,
DVAAVQUE, and DVASIO/DURATION.
QUEUE: The estimated average internal queuing delay
before IOS is able to start an I/O to the
device. This value is estimated by subtracting
the calculated values of control unit, device,
and SIO time from the total estimated response
time for the device.
CNTRL: The estimated average control unit delay to
obtain a free path to the device. This value is
estimated based on percent control unit delay
and I/O rate. These values are data
elements DVAPCCUB and DVASIO/DURATION.
DEVICE: The estimated average delay to reach the device
when the control unit and channel are both free.
This value is estimated based on percent reserve
delay and the I/O rate. These values are
data elements DVAPCRDL and DVASIO/DURATION.
SIO: The estimated average device I/O time. This
value includes channel control word (CCW) fetch,
latency, data transfer, and missed rotational
positioning sensing (RPS) reconnects. This
value is estimated based on the percent device
activity and the I/O rate. These values are
data elements DVAPCACT and DVASIO/DURATION.
To assist in the interpretation of the components of I/O, the
values of the I/O component times are plotted over a range of
60 milliseconds. This plot is presented on the right-hand
side of the report. The characters used to denote the I/O
components are:
Q - The internal queuing delay for the device.
C - The control unit delay for the device.
D - The device delay. Device delay results from RESERVE
CCWs that are issued to the device by applications
that need the device exclusively during some update
process.
S - The I/O time. As was mentioned above, this value
includes CCW fetch, latency, data transfer, and
missed RPS reconnects.
Each character represents one millisecond. The calculated
values are rounded up by adding 0.49 milliseconds to the
calculated values. Values exceeding 60 milliseconds are
represented by a plus sign at the extreme right hand of the
plot.
CA MICS Performance Manager DASD I/O RESPONSE TIME COMPONENT ANALYSIS INTERVAL START: 04JANyy:08:59 INTERVAL END : 04JANyy:10:58 DURATION : 2:00:00 SYSID : SYSA ---------------RESPONSE TIME COMPONENTS (MS)---------------- DEV DEVICE SIO % --------AVERAGE TIME (MS)--------- . 1 . 2 . 3 . 4 . 5 . 6 ADR VOLSER TYPE RATE BUSY RESP QUEUE CNTRL DEVICE SIO 123456789012345678901234567890123456789012345678901234567890 ---- ------ -------- ----- ----- ------ ------ ------ ------ ------ ------------------------------------------------------------ 240 SYSTSO 3330-11 3.0 9.8 42.3 5.6 2.1 2.2 32.3 QQQQQQCCDDSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS 248 STOR11 3350 1.0 3.0 34.0 0.9 2.1 1.6 29.4 QCCDDSSSSSSSSSSSSSSSSSSSSSSSSSSSSS 25E TTF569 3350 1.2 3.3 32.9 1.2 3.6 0.8 27.3 QCCCCDSSSSSSSSSSSSSSSSSSSSSSSSSSS 26C SPOOL3 3380 2.8 6.3 30.3 4.3 1.2 2.1 22.8 QQQQCDDSSSSSSSSSSSSSSSSSSSSSSS 26D SPOOL4 3380 2.8 6.1 30.0 4.8 1.3 2.0 22.0 QQQQQCDDSSSSSSSSSSSSSSSSSSSSSS 260 SPCKPT 3380 3.9 14.9 64.9 1.5 0.0 25.1 38.4 QDDDDDDDDDDDDDDDDDDDDDDDDDSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS+ 264 SPOOL2 3380 3.2 11.1 50.2 9.3 3.2 3.4 34.2 QQQQQQQQQCCCDDDSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS 268 SPOOL1 3380 2.6 6.3 32.9 5.3 1.3 2.4 23.8 QQQQQCDDSSSSSSSSSSSSSSSSSSSSSSSS 3E0 STOR13 3350 1.8 4.5 29.1 1.8 1.0 1.6 24.7 QQCDDSSSSSSSSSSSSSSSSSSSSSSSSS 3E1 PAG3E1 3350 2.3 13.3 73.0 8.3 5.2 1.3 58.3 QQQQQQQQCCCCCDSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS+ 3E8 STOR14 3350 1.9 4.2 24.3 1.2 0.5 0.7 21.9 QDSSSSSSSSSSSSSSSSSSSSSS 322 AVPTWO 3330-11 1.1 4.1 38.4 0.3 0.0 0.0 38.2 SSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS 328 LIBTSO 3330-11 1.2 2.5 22.1 0.7 0.4 0.6 20.5 QDSSSSSSSSSSSSSSSSSSSSS 363 SFAD04 3350 1.1 2.4 22.8 0.6 0.5 0.0 21.7 QSSSSSSSSSSSSSSSSSSSSSS 4B0 STORE5 3350 1.0 3.0 35.5 1.1 2.1 3.1 29.2 QCCDDDSSSSSSSSSSSSSSSSSSSSSSSSSSSSS 467 TTF550 3350 1.1 1.9 20.1 1.7 1.1 0.2 17.0 QQCSSSSSSSSSSSSSSSSS 47A TTF568 3350 1.1 3.2 32.6 1.7 1.0 1.6 28.3 QQCDDSSSSSSSSSSSSSSSSSSSSSSSSSSSS 48E TTF571 3350 1.2 2.2 21.5 1.3 0.8 0.8 18.6 QCDSSSSSSSSSSSSSSSSSSS 490 PAG490 3350 2.3 13.0 68.3 7.4 4.7 0.0 56.3 QQQQQQQCCCCCSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS+ 52A SYSTSS 3350 10.8 13.5 23.1 5.0 0.3 5.3 12.5 QQQQQDDDDDSSSSSSSSSSSS 528 PAG528 3350 2.2 15.2 90.5 12.4 7.8 2.4 67.9 QQQQQQQQQQQQCCCCCCCCDDSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS+ 53E LIBSHR 3350 3.1 7.4 44.8 5.8 1.0 14.0 23.9 QQQQQQCDDDDDDDDDDDDDDSSSSSSSSSSSSSSSSSSSSSSSS 533 TTF533 3350 1.7 3.7 35.3 4.0 0.9 8.2 22.1 QQQQCDDDDDDDDSSSSSSSSSSSSSSSSSSSSSS 535 XXXACC 3350 1.5 4.1 34.2 1.4 0.9 5.0 27.0 QCDDDDDSSSSSSSSSSSSSSSSSSSSSSSSSSS 9C0 CATPAK 3330 3.9 8.5 25.7 3.2 0.7 0.0 21.8 QQQCSSSSSSSSSSSSSSSSSSSSSS 9C9 PAG9C9 3350 2.3 12.9 67.5 7.5 4.6 0.0 55.5 QQQQQQQCCCCCSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS+ 9DB TTF524 3350 1.0 1.7 18.9 1.7 0.0 0.0 17.2 QQSSSSSSSSSSSSSSSSS 93D SFAD01 3350 1.5 3.1 23.0 1.9 0.5 0.3 20.4 QQSSSSSSSSSSSSSSSSSSSS 961 SFAD07 3350 2.8 5.3 22.5 1.9 0.4 1.1 19.1 QQDSSSSSSSSSSSSSSSSSSS 963 TTF559 3350 2.8 5.4 29.2 4.1 1.1 4.7 19.3 QQQQCDDDDDSSSSSSSSSSSSSSSSSSS 965 PACK02 3350 1.6 4.0 34.6 2.9 2.5 3.1 26.0 QQQCCCDDDSSSSSSSSSSSSSSSSSSSSSSSSSS 966 XXXACT 3350 1.9 4.4 25.6 1.4 0.1 0.9 23.3 QDSSSSSSSSSSSSSSSSSSSSSSS 967 PAG967 3350 1.8 3.8 25.5 1.9 1.3 1.3 21.0 QQCDSSSSSSSSSSSSSSSSSSSSS
Figure 2-97. I/O Response Time Component Analysis Report for MVS/370
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