Commit Graph

7 Commits

Author SHA1 Message Date
Peter Oberparleiter d15e36cf24 chpstat: Add options to select IEC units for scaling
Add options to select power-of-two based IEC units such as KiB/s
(1024 B/s) for scaling throughput values in human readable reports.

Option            Scaling factor
================================
--scale ki        1024
--scale mi        1048576
--scale gi        1073741824
--scale auto-iec  IEC units

Reviewed-by: Jimmy Brisson <jbrisson@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
2025-09-15 11:12:15 +02:00
Peter Oberparleiter 4b76530788 chpstat: Use SI units for default scaling
chpstat uses power-of-two based IEC units such as KiB/s (1024 B/s) when
scaling throughput values in human readable reports. A user interpreting
these numbers can easily be confused by chpstat's default column header
("B/s") to assume that numbers are scaled using power-of-ten based SI
units such as kB/s (1000 B/s).

In addition, users that have worked with similar z/OS tooling to display
channel path activity are used to SI-based scaling, which increases the
chance of chpstat reports being misinterpreted.

To reduce this confusion, use SI units for throughput scaling:

Option          Old factor      New factor
==========================================
--scale k       1024            1000
--scale m       1048576         1000000
--scale g       1073741824      1000000000
--scale auto    IEC units       SI units

Note that machine-readable format produced via option --format is not
affected by scaling.

Reviewed-by: Jimmy Brison <jbrisson@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
2025-09-15 11:12:15 +02:00
Peter Oberparleiter cb1c002bed chpstat: Ensure consistent table group spacing
In tabular output, chpstat adds an additional space between columns
of different groups (e.g. between READ and WRITE data). Currently this
is done by increasing the column width of the first column in a group.

Depending on the value displayed in this first column of a group, the
spacing may vanish, and under certain circumstances, the precision of
auto-scaled *_PART columns may be higher than the precision of the
related *_TOTAL columns, resulting in a confusing view.

Example:

DPU   READ(B/s)  WRITE(B/s)
 ID  PART TOTAL  PART TOTAL
  6 10.7M 10.7M 10.8M 10.8M
  6  0.00 11.3K  0.00  0.00
   ^^          ^^

Fix this by consistently adding padding between column groups without
increasing the column width of the first column of a group. Also ensure
the same width for *_PART and *_TOTAL columns.

Reviewed-by: Jimmy Brisson <jbrisson@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
2025-09-15 11:12:15 +02:00
Peter Oberparleiter 6520070a46 chpstat: Fix invalid utilization data on older kernels
On kernels without support for the new "measurement_chars_full" CHPID
sysfs attribute, chpstat displays invalid utilization numbers (nan/inf).
This is due to an invalid buffer address calculation when reading the
old "measurement_chars" attribute.

Fix this by using the correct buffer address calculation.

Fixes: 026ecbafea ("chpstat: Add support for full CMCB")
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2024-12-19 21:45:37 +01:00
Peter Oberparleiter 026ecbafea chpstat: Add support for full CMCB
Newer kernels provide the full, unfiltered Channel-Measurements
Characteristics Block (CMCB) via a new sysfs attribute named
"measurement_chars_full".

Add support for reading the full CMCB data if available in preparation
of new tool functions that will make use of this data.

Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>
2024-11-29 15:52:24 +01:00
Peter Oberparleiter 54e175a783 chpstat: Improve --cmg value parsing
Switch from atoi() to existing parse_int() helper function for parsing
the integer --cmg argument to better handle invalid values such as
numbers followed by an unsupported suffix (e.g. 1x).

Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
2024-11-22 17:15:59 +01:00
Peter Oberparleiter cb77faeae7 chpstat: add tool to display channel-path statistics
Add a new tool named chpstat that can be used to view channel-path
statistics such as utilization and I/O throughput, and to query and
control the status of the channel-path statistics function.

Note: Channel-path statistics are only available on systems running in
      an LPAR or DPM partition.

When run without further options, data for all channel-paths is
displayed repeatedly with a 5 second delay in table format.

Example output:

      CHANNEL-PATH       UTILIZATION(%)   READ(B/s)  WRITE(B/s)
  ID TYP CMG SHR SPEED  PART TOTAL  BUS  PART TOTAL  PART TOTAL
  1d  25   2   1     -  7.16  7.50 7.50  129M  129M  0.00  161K
  21  1b   2   1   32G  0.00  0.00 0.00  0.00  0.00  0.00  0.00
  34  1b   2   1   32G  0.00  0.00 0.00  0.00  0.00  0.00  0.00
  61  25   2   1     -  0.00  0.01 0.00  0.00 2.00K  0.00  307K
  63  25   2   1     -  0.00  0.01 0.00  0.00  0.00  0.00  381K
  bd  11   2   1   10G     -     -    - 529.8 532.1 616.3 616.3

Reviewed-by: Vineeth Vijayan <vneethv@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Steffen Eiden <seiden@linux.ibm.com>
2024-05-27 16:52:27 +02:00