CFROPTS parameter - Revision history

Alex: /* Summary */

2015-04-07T02:00:11Z

Summary

← Older revision		Revision as of 02:00, 7 April 2015
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	<dd>System		<dd>System
	<dt>Where set		<dt>Where set
	<dd>On User 0's parameter line ~~or reset by system manager~~		<dd>On User 0's parameter line
	<dt>Related products		<dt>Related products
	<dd>All		<dd>All

JAL: misc cleanup

2015-03-18T20:45:46Z

misc cleanup

← Older revision		Revision as of 20:45, 18 March 2015
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	==Description==		==Description==
	<p>The CFROPTS parameter can affect the handling of critical file resource enqueuing conflicts. The parameter contains bit settings with the following possible values:</p>		<p>
			The <var>CFROPTS</var> parameter can affect the handling of critical file resource enqueuing conflicts. The parameter contains bit settings with the following possible values:</p>
	<table>		<table>
	<tr><th>		<tr class="head"><th>Setting </th><th>Meaning</th></tr>
	<p>Setting ~~</p>~~
	</th><th>		<tr><th><var>X'01'</var></th>
	<p>Meaning~~</p>~~		<td>Indicates that strict fair share enqueuing will be used. This prevents one thread from sneaking ahead of another in obtaining a critical file resource lock because it happens to be running before a thread that had been waiting for the lock before it. While this "sneaking ahead" can reduce CFR lock waits and associated swapping at low loads (because the sneaking thread might finish before the waiting one ever runs), it can increase waits and thrashing at high loads, and it can cause abysmal response times for updating threads.
	</th></tr>		<p>
	<tr><th ~~align="right"~~><var>		The increased server swapping when <var>CFROPTS</var> X'01' is not set is caused by a variant of the [http://en.wikipedia.org/wiki/Thundering_herd_problem thundering herd problem].</p></td></tr>
	<p>X'01' ~~</p>~~
	</var></th><td>
	<p>Indicates that strict fair share enqueuing will be used. This prevents one thread from sneaking ahead of another in obtaining a critical file resource lock because it happens to be running before a thread that had been waiting for the lock before it. While this "sneaking ahead" can reduce CFR lock waits and associated swapping at low loads (because the sneaking thread might finish before the waiting one ever runs) it can increase waits and thrashing at high loads and can cause abysmal response times for updating threads. The increased server swapping when CFROPTS X'01' is not set is caused by a variant of the [http://en.wikipedia.org/wiki/Thundering_herd_problem thundering herd problem].</p>
	</td></tr>
	</table>		</table>

	[[Category:System parameters]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

Alex: Created page with "{{Template:AUDITOPT parameter subtitle}} ==Summary==

Default value
X'00'
Parameter type
System
Where set
On User 0's parameter line or reset by sy..."

2015-03-17T16:45:52Z

Created page with "{{Template:AUDITOPT parameter subtitle}} ==Summary== <dl> <dt>Default value <dd>X'00' <dt>Parameter type <dd>System <dt>Where set <dd>On User 0's parameter line or reset by sy..."

New page

{{Template:AUDITOPT parameter subtitle}}
==Summary==
<dl>
<dt>Default value
<dd>X'00'
<dt>Parameter type
<dd>System
<dt>Where set
<dd>On User 0's parameter line or reset by system manager
<dt>Related products
<dd>All
<dt>Introduced
<dd><var class="product">Model 204 V7.6</var>
</dl>

==Description==
The CFROPTS parameter can affect the handling of critical file resource enqueuing conflicts. The parameter contains bit settings with the following possible values:
<table>
<tr><th>
Setting 
</th><th>
Meaning
</th></tr>
<tr><th align="right"><var>
X'01' 
</var></th><td>
Indicates that strict fair share enqueuing will be used. This prevents one thread from sneaking ahead of another in obtaining a critical file resource lock because it happens to be running before a thread that had been waiting for the lock before it. While this "sneaking ahead" can reduce CFR lock waits and associated swapping at low loads (because the sneaking thread might finish before the waiting one ever runs) it can increase waits and thrashing at high loads and can cause abysmal response times for updating threads. The increased server swapping when CFROPTS X'01' is not set is caused by a variant of the [http://en.wikipedia.org/wiki/Thundering_herd_problem thundering herd problem].
</td></tr>
</table>
[[Category:System parameters]]
[[Category:Parameters]]

CFROPTS parameter - Revision history

Alex: /* Summary */

JAL: misc cleanup

Alex: Created page with "{{Template:AUDITOPT parameter subtitle}} ==Summary== Default value X'00' Parameter type System Where set On User 0's parameter line or reset by sy..."

Alex: Created page with "{{Template:AUDITOPT parameter subtitle}} ==Summary==

Default value
X'00'
Parameter type
System
Where set
On User 0's parameter line or reset by sy..."