STRUCT CMBDATA

Section: The ccw bus (9)
Updated: February 2011
Index Return to Main Contents

NAME

struct_cmbdata - channel measurement block data for user space

SYNOPSIS

struct cmbdata {
  __u64 size;
  __u64 elapsed_time;
  __u64 ssch_rsch_count;
  __u64 sample_count;
  __u64 device_connect_time;
  __u64 function_pending_time;
  __u64 device_disconnect_time;
  __u64 control_unit_queuing_time;
  __u64 device_active_only_time;
  __u64 device_busy_time;
  __u64 initial_command_response_time;
};

MEMBERS

size

: size of the stored data

elapsed_time

: time since last sampling

ssch_rsch_count

: number of ssch and rsch

sample_count

: number of samples

device_connect_time

: time of device connect

function_pending_time

: time of function pending

device_disconnect_time

: time of device disconnect

control_unit_queuing_time

: time of control unit queuing

device_active_only_time

: time of device active only

device_busy_time

: time of device busy (ext. format)

initial_command_response_time

: initial command response time (ext. format)

DESCRIPTION

All values are stored as 64 bit for simplicity, especially in 32 bit emulation mode. All time values are normalized to nanoseconds. Currently, two formats are known, which differ by the size of this structure, i.e. the last two members are only set when the extended channel measurement facility (first shipped in z990 machines) is activated. Potentially, more fields could be added, which would result in a new ioctl number.

AUTHOR

Cornelia Huck <cornelia.huck@de.ibm.com>