SCHDOPT1 parameter - Revision history

JDamon at 20:57, 15 February 2022

2022-02-15T20:57:34Z

← Older revision		Revision as of 20:57, 15 February 2022
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	Flags that, in addition to the [[SCHDOPT parameter]], ~~allows~~ one to tune scheduler behavior. <var>SCHDOPT1</var> is a parameter where the following bits control a certain aspects of scheduler behavior:		Flags that, in addition to the [[SCHDOPT parameter]], allow one to tune scheduler behavior. <var>SCHDOPT1</var> is a parameter where the following bits control certain aspects of scheduler behavior:

	<table>		<table>
	<tr class="head"><th>Setting</th><th>Meaning</th></tr>		<tr class="head"><th>Setting</th><th>Meaning</th></tr>
	<tr><th align="right"><var>X'01'</var></th>		<tr><th align="right"><var>X'01'</var></th>
	<td>~~Indicates that threads that are running~~ on a zIIP~~-capable SRB and need to do journal~~ I/O ~~do not "bounce"~~ to a ~~non-~~zIIP subtask to do the ~~journal~~ or ~~checkpoint~~ I/O ~~but simply perform it~~ on the maintask. ~~Since generally very little processing~~ is ~~involved in doing journal or checkpoint I/O, sending a thread~~ to an MP ~~task~~ to do the I/O ~~only increases latency~~ and ~~saves no maintask processing overhead~~.		<td>Journal and checkpoint I/O cannot be performed on a zIIP subtask; that I/O operation must start on an MP subtask or on the maintask. When this parameter is set to X’01’, a user running on a zIIP subtask who needs to write to the CCAJRNL/JLOG or CHKPOINT data set, will be switched to the maintask, not an MP subtask, and the I/O operation will start on the maintask. Waits for an MP subtask to become available on a busy system can be significantly longer than waits for the maintask to become available. There is also more overhead to switch to an MP subtask than to the maintask. Consequently, this feature reduces wait times to start an I/O to the CCAJRNL/JLOG and CHKPOINT data sets when a unit of work is running on a zIIP subtask.

	This setting also prevents a thread running on a non-zIIP task and that has to wait for another thread doing journal or checkpoint I/O before doing the same from bouncing between maintask and subtask to do the I/O – when the X'01' bit is set, the I/O will be performed on the maintask, again reducing I/O latency. This bit has a much more significant effect if zIIP subtasks are in use. For more information about zIIP processing, refer to the [[~~SCHDOPT~~ parameter]] and [[~~AMPSUBZ~~ parameter]] ~~descriptions~~.		For more information about zIIP processing, refer to the descriptions for the[[AMPSUBZ parameter]], [[MPDELAYZ parameter]], [[NMPSUBZ parameter]], [[SCHDOFLS parameter]] and [[SCHDOFLZ parameter]].
	</td></tr>		</td></tr>
	</table>		</table>

Alex at 13:35, 21 June 2020

2020-06-21T13:35:18Z

@@ Line 1: / Line 1: @@
-{{Template:SCHDOPT1 parameter subtitle}}
+Flags that, in addition to the [[SCHDOPT parameter]], allows one to tune scheduler behavior. <var>SCHDOPT1</var> is a parameter where the following bits control a certain aspects of scheduler behavior:
 <table>
 <tr class="head"><th>Setting</th><th>Meaning</th></tr>
 <tr><th align="right"><var>X'01'</var></th>
-<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do.
+<td>Indicates that threads that are running on a zIIP-capable SRB and need to do journal I/O do not "bounce" to a non-zIIP subtask to do the journal or checkpoint I/O but simply perform it on the maintask. Since generally very little processing is involved in doing journal or checkpoint I/O, sending a thread to an MP task to do the I/O only increases latency and saves no maintask processing overhead.
-<p><b>Note:</b> As of version 7.6 of Model&nbsp;204, this setting is disabled (has no effect), because the behavior it invoked is automatically on in those versions.</p></td></tr>
 </table>

DCameron: /* Summary */

2017-05-24T13:42:53Z

Summary

← Older revision		Revision as of 13:42, 24 May 2017
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	<dd>On User 0's parameter line or reset by system manager.		<dd>On User 0's parameter line or reset by system manager.
	<dt>Related products		<dt>Related products
	<dd><var>[[MP/204#Multiprocessing_.28MP.2F204.29\|MP/204]]</var> and M204 HPO		<dd><var>[[MP/204#Multiprocessing_.28MP.2F204.29\|MP/204]]</var> and <var>[[Performance_monitoring_and_tuning#Offloading_Model_204_work_to_zIIP_processors\|M204 HPO]]</var>
	<dt>Introduced		<dt>Introduced
	<dd><var class="product">Model 204 V7.4</var>		<dd><var class="product">Model 204 V7.4</var>

DCameron: /* Summary */

2017-05-24T13:23:41Z

Summary

← Older revision		Revision as of 13:23, 24 May 2017
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	<dd>On User 0's parameter line or reset by system manager.		<dd>On User 0's parameter line or reset by system manager.
	<dt>Related products		<dt>Related products
	<dd>MP/204 and M204 HPO		<dd><var>[[MP/204#Multiprocessing_.28MP.2F204.29\|MP/204]]</var> and M204 HPO
	<dt>Introduced		<dt>Introduced
	<dd><var class="product">Model 204 V7.4</var>		<dd><var class="product">Model 204 V7.4</var>

DCameron: /* Summary */

2017-05-24T13:21:42Z

Summary

← Older revision		Revision as of 13:21, 24 May 2017
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	<dd>On User 0's parameter line or reset by system manager.		<dd>On User 0's parameter line or reset by system manager.
	<dt>Related products		<dt>Related products
	<dd>~~All~~		<dd>MP/204 and M204 HPO
	<dt>Introduced		<dt>Introduced
	<dd><var class="product">Model 204 V7.4</var>		<dd><var class="product">Model 204 V7.4</var>

JAL: add clarifying phrase

2016-08-15T21:29:09Z

add clarifying phrase

← Older revision		Revision as of 21:29, 15 August 2016
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	<tr><th align="right"><var>X'01'</var></th>		<tr><th align="right"><var>X'01'</var></th>
	<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do.		<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do.
	<p><b>Note:</b> As of version 7.6 of Model 204, this setting is disabled (has no effect).</p></td></tr>		<p><b>Note:</b> As of version 7.6 of Model 204, this setting is disabled (has no effect), because the behavior it invoked is automatically on in those versions.</p></td></tr>
	</table>		</table>

JAL: misc cleanup

2015-03-16T16:31:46Z

misc cleanup

← Older revision		Revision as of 16:31, 16 March 2015
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	==Description==		==Description==

	Allows an MP subtask to handle [[Creating server data sets (CCASERVR)#Overview\|server swapping]], if applicable.		Allows an MP subtask to handle [[Creating server data sets (CCASERVR)#Overview\|server swapping]], if applicable.

	<var>SCHDOPT1</var> is useful when zIIP is handling server swapping and needs help from an MP subtask.		<var>SCHDOPT1</var> is useful when a [[Performance monitoring and tuning#Offloading Model 204 work to zIIP processors\|zIIP processor]] is handling server swapping and needs help from an MP subtask.

	Setting X'01' is relevant only to sites running MP/204.		Setting X'01' is relevant only to sites running MP/204.
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	<tr class="head"><th>Setting</th><th>Meaning</th></tr>		<tr class="head"><th>Setting</th><th>Meaning</th></tr>
	<tr><th align="right"><var>X'01'</var></th>		<tr><th align="right"><var>X'01'</var></th>
	<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do. <p><b>Note:</b> As of version 7.6 of Model 204, this setting is disabled (has no effect).</p></td></tr>		<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do.
			<p><b>Note:</b> As of version 7.6 of Model 204, this setting is disabled (has no effect).</p></td></tr>
	</table>		</table>

	For more information about zIIP processing, refer to [[SCHDOPT parameter\|SCHDOPT~~: Scheduler operation and accounting]] and to [[Performance monitoring and tuning#Offloading Model 204 work to zIIP processors\|Offloading Model 204 work to zIIP processors~~]].		For more information about zIIP processing, refer to the <var>[[SCHDOPT parameter\|SCHDOPT]]</var> parameter description.

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

ELowell: /* Description */

2015-03-13T15:55:45Z

Description

← Older revision		Revision as of 15:55, 13 March 2015
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	==Description==		==Description==
	~~<p>~~
	Allows an MP subtask to handle [[Creating server data sets (CCASERVR)#Overview\|server swapping]], if applicable.~~</p>~~		Allows an MP subtask to handle [[Creating server data sets (CCASERVR)#Overview\|server swapping]], if applicable.
	~~<p>~~
	<var>SCHDOPT1</var> is useful when zIIP is handling server swapping and needs help from an MP subtask.~~</p>~~		<var>SCHDOPT1</var> is useful when zIIP is handling server swapping and needs help from an MP subtask.
	~~<p>~~
	Setting X'01' is relevant only to sites running MP/204.~~</p>~~		Setting X'01' is relevant only to sites running MP/204.
	<table>		<table>
	<tr class="head"><th>Setting</th><th>Meaning</th></tr>		<tr class="head"><th>Setting</th><th>Meaning</th></tr>

	<tr><th align="right"><var>X'01'</var></th>		<tr><th align="right"><var>X'01'</var></th>
	<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do.</td></tr>		<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do. <p><b>Note:</b> As of version 7.6 of Model 204, this setting is disabled (has no effect).</p></td></tr>
	</table>		</table>

	~~<p>~~		For more information about zIIP processing, refer to [[SCHDOPT parameter\|SCHDOPT: Scheduler operation and accounting]] and to [[Performance monitoring and tuning#Offloading Model 204 work to zIIP processors\|Offloading Model 204 work to zIIP processors]].
	For more information about zIIP processing, refer to [[SCHDOPT parameter\|SCHDOPT: Scheduler operation and accounting]] and to [[Performance monitoring and tuning#Offloading Model 204 work to zIIP processors\|Offloading Model 204 work to zIIP processors]]. ~~</p>~~

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

JAL: add link

2015-02-18T19:21:20Z

add link

← Older revision		Revision as of 19:21, 18 February 2015
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	==Description==		==Description==
	<p>		<p>
	Allows an MP subtask to handle server swapping, if applicable.</p>		Allows an MP subtask to handle [[Creating server data sets (CCASERVR)#Overview\|server swapping]], if applicable.</p>
	<p>		<p>
	<var>SCHDOPT1</var> is useful when zIIP is handling server swapping and needs help from an MP subtask.</p>		<var>SCHDOPT1</var> is useful when zIIP is handling server swapping and needs help from an MP subtask.</p>

JAL: add link

2015-02-18T19:12:52Z

add link

← Older revision		Revision as of 19:12, 18 February 2015
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	{{Template:SCHDOPT1 parameter subtitle}}		{{Template:SCHDOPT1 parameter subtitle}}

	==Summary==		==Summary==
	<dl>		<dl>
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	<dd><var class="product">Model 204 V7.4</var>		<dd><var class="product">Model 204 V7.4</var>
	</dl>		</dl>

	==Description==		==Description==
	<p>Allows an MP subtask to handle server swapping, if applicable.</p>		<p>
	<p>SCHDOPT1 is useful when zIIP is handling server swapping and needs help from an MP subtask.</p>		Allows an MP subtask to handle server swapping, if applicable.</p>
	<p>Setting X'01' is relevant only to sites running MP/204.</p>		<p>
			<var>SCHDOPT1</var> is useful when zIIP is handling server swapping and needs help from an MP subtask.</p>
			<p>
			Setting X'01' is relevant only to sites running MP/204.</p>
	<table>		<table>
	<tr><th>Setting</th><th>Meaning</th></tr>		<tr class="head"><th>Setting</th><th>Meaning</th></tr>
	<tr><th align="right"><var>X'01'</var></th><td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do.</td></tr>
			<tr><th align="right"><var>X'01'</var></th>
			<td>(MP/204 only) Allows an MP subtask to handle server swapping if the subtask has nothing else to do.</td></tr>
	</table>		</table>
	<p>For more information about zIIP processing, refer to [[SCHDOPT parameter\|SCHDOPT: Scheduler operation and accounting]] and to ~~the Rocket <var class="product">~~Model~~ ~~204~~</var> System Manager's Guide~~. </p>
			<p>
			For more information about zIIP processing, refer to [[SCHDOPT parameter\|SCHDOPT: Scheduler operation and accounting]] and to [[Performance monitoring and tuning#Offloading Model 204 work to zIIP processors\|Offloading Model 204 work to zIIP processors]]. </p>

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