linux-hardened/drivers/s390
Stefan Weinhuber 4fa52aa7a8 [S390] dasd: add enhanced DASD statistics interface
This patch extends the DASD statistics to allow for a more detailed
analysis of DASD I/O operations. In particular we want the statistics
to provide answers to the following questions:
- How many requests used a PAV alias?
- How many requests used High Performance FICON?
- How do read request perform versus write requests?

The existing DASD statistics interface has several shortcomings
- The interface for global data is a formatted text table in procfs
  (/proc/dasd/statistics). The layout is meant for human readers and
  is not to easy to parse. If values get to large for the table
  layout, they get scaled down.
- The statistics which are collected per block device can be
  accessed via an ioctl interface, which can only be extended by
  defining a new ioctl.
- There is no statistics interface for individual PAV base and alias
  devices.

To overcome theses shortcomings we create a new DASD statistics
interface in debugfs. This interface will contain one entry for global
data, one per DASD block device, and one per DASD base and alias
device. Each file contains the statistic data in easy to parse
name/value and name/array pairs. The existing interfaces will remain
functional, but they will not be extended.

Signed-off-by: Stefan Weinhuber <wein@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
2011-07-24 10:48:23 +02:00
..
block [S390] dasd: add enhanced DASD statistics interface 2011-07-24 10:48:23 +02:00
char [S390] kconfig: remove tape interface support comment 2011-07-24 10:48:00 +02:00
cio [S390] qdio: clear shared DSCI before scheduling the queue handler 2011-07-24 10:48:00 +02:00
crypto [S390] ap: toleration support for ap device type 10 2011-07-24 10:48:22 +02:00
kvm [S390] irq: merge irq.c and s390_ext.c 2011-05-26 09:48:24 +02:00
net qeth: do vlan cleanup 2011-07-21 13:47:57 -07:00
scsi [S390] qdio: Split SBAL entry flags 2011-06-06 14:14:56 +02:00
Makefile [S390] split/move machine check handler code 2009-03-26 15:24:10 +01:00