forked from Minki/linux
4fa52aa7a8
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> |
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