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<html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=ANSI_X3.4-1968" /><title>struct cmbdata</title><meta name="generator" content="DocBook XSL Stylesheets V1.75.2" /><link rel="home" href="index.html" title="Writing s390 channel device drivers" /><link rel="up" href="ch02s03.html" title="The channel-measurement facility" /><link rel="prev" href="ch02s03.html" title="The channel-measurement facility" /><link rel="next" href="re40.html" title="enable_cmf" /></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center"><span>struct cmbdata</span></th></tr><tr><td width="20%" align="left"><a accesskey="p" href="ch02s03.html">Prev</a> </td><th width="60%" align="center">The channel-measurement facility</th><td width="20%" align="right"> <a accesskey="n" href="re40.html">Next</a></td></tr></table><hr /></div><div class="refentry" title="struct cmbdata"><a id="API-struct-cmbdata"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>struct cmbdata —
channel measurement block data for user space
</p></div><div class="refsynopsisdiv" title="Synopsis"><h2>Synopsis</h2><pre class="programlisting">
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;
}; </pre></div><div class="refsect1" title="Members"><a id="id3094897"></a><h2>Members</h2><div class="variablelist"><dl><dt><span class="term">size</span></dt><dd><p>
size of the stored data
</p></dd><dt><span class="term">elapsed_time</span></dt><dd><p>
time since last sampling
</p></dd><dt><span class="term">ssch_rsch_count</span></dt><dd><p>
number of ssch and rsch
</p></dd><dt><span class="term">sample_count</span></dt><dd><p>
number of samples
</p></dd><dt><span class="term">device_connect_time</span></dt><dd><p>
time of device connect
</p></dd><dt><span class="term">function_pending_time</span></dt><dd><p>
time of function pending
</p></dd><dt><span class="term">device_disconnect_time</span></dt><dd><p>
time of device disconnect
</p></dd><dt><span class="term">control_unit_queuing_time</span></dt><dd><p>
time of control unit queuing
</p></dd><dt><span class="term">device_active_only_time</span></dt><dd><p>
time of device active only
</p></dd><dt><span class="term">device_busy_time</span></dt><dd><p>
time of device busy (ext. format)
</p></dd><dt><span class="term">initial_command_response_time</span></dt><dd><p>
initial command response time (ext. format)
</p></dd></dl></div></div><div class="refsect1" title="Description"><a id="id3095032"></a><h2>Description</h2><p>
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.
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