MPDELAY parameter - Revision history

JAL: misc formatting

2016-08-02T20:57:54Z

misc formatting

← Older revision		Revision as of 20:57, 2 August 2016
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	This parameter specifies the number of milliseconds to delay starting additional MP subtasks when an extra one should be started based on <var>[[SCHDOFL parameter\|SCHDOFL]]</var>.</p>		This parameter specifies the number of milliseconds to delay starting additional MP subtasks when an extra one should be started based on <var>[[SCHDOFL parameter\|SCHDOFL]]</var>.</p>
	<p>		<p>
	The default value of 0 means that if the number of units of work queued to MP subtasks exceeds some limit as indicated by the <var>SCHDOFL</var> parameter, an MP subtask is immediately started. The benefit of setting <var>MPDELAY</var> to a non-zero value is ~~that~~ it prevents a large number of MP subtasks ~~being started when a burst of units arrive (a common occurrence when dealing critical file resource conflicts)~~ only to have most of them quickly deactivate because too many were started for the amount of work to be done. ~~Activating~~ and deactivating MP subtasks can have non-trivial CPU costs.</p>		The default value of 0 means that if the number of units of work queued to MP subtasks exceeds some limit as indicated by the <var>SCHDOFL</var> parameter, an MP subtask is immediately started. The benefit of setting <var>MPDELAY</var> to a non-zero value is seen when a burst of work units arrive: it prevents the immediate starting of a large number of MP subtasks only to have most of them quickly deactivate because too many were started for the amount of work to be done. Such demand bursts are a common occurrence when dealing with critical file resource conflicts, and activating and deactivating MP subtasks can have non-trivial CPU costs.</p>
	<p>		==Usage notes==
	<var>MPDELAY</var> has no effect if either of these is true: ~~</p>~~		<ul>
			<li><var>MPDELAY</var> has no effect if either of these is true:
	<ul>		<ul>
	<li>MP/204 is not in effect in an Online (<var>NMPSUBS</var> is 0).</li>		<li>MP/204 is not in effect in an Online (<var>NMPSUBS</var> is 0).</li>
	<li>The number of active subtasks (<var>AMPSUBS</var>) is set to 0 or 1. (If <var>AMPSUBS</var> is 1, an MP subtask is activated as soon as there is any offloadable work, and it then runs until there is no more offloadable work for it to process.)</li>		<li>The number of active subtasks (<var>AMPSUBS</var>) is set to 0 or 1. (If <var>AMPSUBS</var> is 1, an MP subtask is activated as soon as there is any offloadable work, and it then runs until there is no more offloadable work for it to process.)</li>
			</ul></li>

			<li>If <var>MPDELAY</var> is set, consider reducing <var>SCHDOFL</var> to 1 or 0, since both parameters attempt to solve the same problem (too much MP subtask activation/deactivation). Using both parameters can reduce throughput or response times.</li>
	</ul>		</ul>
	~~<p>~~
	If <var>MPDELAY</var> is set, consider reducing <var>SCHDOFL</var> to 1 or 0, since both parameters attempt to solve the same problem (too much MP subtask activation/deactivation). Using both parameters can reduce throughput or response times.</p>		==See also==
	~~<p>~~
	The <var>[[MPDELAYZ parameter\|MPDELAYZ]]</var> parameter provides the same functionality as <var>MPDELAY</var> for zIIP/SRB subtasks.		The <var>[[MPDELAYZ parameter\|MPDELAYZ]]</var> parameter provides the same functionality as <var>MPDELAY</var> for zIIP/SRB subtasks.
	~~</p>~~

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

JAL: /* Description */ minor wordsmithing

2016-08-02T19:18:11Z

Description: minor wordsmithing

← Older revision		Revision as of 19:18, 2 August 2016
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	</ul>		</ul>
	<p>		<p>
	If <var>MPDELAY</var> is set, ~~it might make sense to reduce~~ <var>SCHDOFL</var> to 1 or ~~maybe even~~ 0 as both parameters attempt to solve the same problem (too much MP subtask activation/deactivation) ~~and using~~ both can reduce throughput or response times.</p>		If <var>MPDELAY</var> is set, consider reducing <var>SCHDOFL</var> to 1 or 0, since both parameters attempt to solve the same problem (too much MP subtask activation/deactivation). Using both parameters can reduce throughput or response times.</p>
	<p>		<p>
	The <var>[[MPDELAYZ parameter\|MPDELAYZ]]</var> parameter provides the same functionality as <var>MPDELAY</var> for zIIP/SRB subtasks.		The <var>[[MPDELAYZ parameter\|MPDELAYZ]]</var> parameter provides the same functionality as <var>MPDELAY</var> for zIIP/SRB subtasks.
	</p>		</p>

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

JAL: add `s`

2016-08-02T18:45:29Z

add <var>s

← Older revision		Revision as of 18:45, 2 August 2016
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	==Description==		==Description==
	<p>		<p>
	This parameter specifies the number of milliseconds to delay starting additional MP subtasks when an extra one should be started based on [[SCHDOFL parameter\|SCHDOFL]].</p>		This parameter specifies the number of milliseconds to delay starting additional MP subtasks when an extra one should be started based on <var>[[SCHDOFL parameter\|SCHDOFL]]</var>.</p>
	<p>		<p>
	The default value of 0 means that if the number of units of work queued to MP subtasks exceeds some limit as indicated by the <var>SCHDOFL</var> parameter, an MP subtask is immediately started. The benefit of setting MPDELAY to a non-zero value is that it prevents a large number of MP subtasks being started when a burst of units arrive (a common occurrence when dealing critical file resource conflicts) only to have most of them quickly deactivate because too many were started for the amount of work to be done. Activating and deactivating MP subtasks can have non-trivial CPU costs.</p>		The default value of 0 means that if the number of units of work queued to MP subtasks exceeds some limit as indicated by the <var>SCHDOFL</var> parameter, an MP subtask is immediately started. The benefit of setting <var>MPDELAY</var> to a non-zero value is that it prevents a large number of MP subtasks being started when a burst of units arrive (a common occurrence when dealing critical file resource conflicts) only to have most of them quickly deactivate because too many were started for the amount of work to be done. Activating and deactivating MP subtasks can have non-trivial CPU costs.</p>
	<p>		<p>
	<var>MPDELAY</var> has no effect if either of these is true: </p>		<var>MPDELAY</var> has no effect if either of these is true: </p>
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	If <var>MPDELAY</var> is set, it might make sense to reduce <var>SCHDOFL</var> to 1 or maybe even 0 as both parameters attempt to solve the same problem (too much MP subtask activation/deactivation) and using both can reduce throughput or response times.</p>		If <var>MPDELAY</var> is set, it might make sense to reduce <var>SCHDOFL</var> to 1 or maybe even 0 as both parameters attempt to solve the same problem (too much MP subtask activation/deactivation) and using both can reduce throughput or response times.</p>
	<p>		<p>
	The [[MPDELAYZ parameter]] provides the same functionality as <var>MPDELAY</var> for zIIP/SRB subtasks.		The <var>[[MPDELAYZ parameter\|MPDELAYZ]]</var> parameter provides the same functionality as <var>MPDELAY</var> for zIIP/SRB subtasks.
	</p>		</p>
	[[Category:System parameters]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

Alex: /* Description */

2016-08-02T05:27:10Z

Description

← Older revision		Revision as of 05:27, 2 August 2016
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	<p>		<p>
	If <var>MPDELAY</var> is set, it might make sense to reduce <var>SCHDOFL</var> to 1 or maybe even 0 as both parameters attempt to solve the same problem (too much MP subtask activation/deactivation) and using both can reduce throughput or response times.</p>		If <var>MPDELAY</var> is set, it might make sense to reduce <var>SCHDOFL</var> to 1 or maybe even 0 as both parameters attempt to solve the same problem (too much MP subtask activation/deactivation) and using both can reduce throughput or response times.</p>
			<p>
			The [[MPDELAYZ parameter]] provides the same functionality as <var>MPDELAY</var> for zIIP/SRB subtasks.
			</p>
	[[Category:System parameters]]		[[Category:System parameters]]
	[[Category:Parameters]]		[[Category:Parameters]]

Alex at 05:09, 2 August 2016

2016-08-02T05:09:55Z

← Older revision		Revision as of 05:09, 2 August 2016
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	{{Template:~~SCHDOFL~~ parameter subtitle}}		{{Template:MPDELAY parameter subtitle}}
	==Summary==		==Summary==
	<dl>		<dl>

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

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

2016-08-02T05:09:30Z

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

New page

{{Template:SCHDOFL parameter subtitle}}
==Summary==
<dl>
<dt>Default value
<dd>0
<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 V7.7</var>
</dl>

==Description==

This parameter specifies the number of milliseconds to delay starting additional MP subtasks when an extra one should be started based on [[SCHDOFL parameter|SCHDOFL]].

The default value of 0 means that if the number of units of work queued to MP subtasks exceeds some limit as indicated by the <var>SCHDOFL</var> parameter, an MP subtask is immediately started. The benefit of setting MPDELAY to a non-zero value is that it prevents a large number of MP subtasks being started when a burst of units arrive (a common occurrence when dealing critical file resource conflicts) only to have most of them quickly deactivate because too many were started for the amount of work to be done. Activating and deactivating MP subtasks can have non-trivial CPU costs.

<var>MPDELAY</var> has no effect if either of these is true: 
<ul>
<li>MP/204 is not in effect in an Online (<var>NMPSUBS</var> is 0).</li>
<li>The number of active subtasks (<var>AMPSUBS</var>) is set to 0 or 1. (If <var>AMPSUBS</var> is 1, an MP subtask is activated as soon as there is any offloadable work, and it then runs until there is no more offloadable work for it to process.)</li>
</ul>

If <var>MPDELAY</var> is set, it might make sense to reduce <var>SCHDOFL</var> to 1 or maybe even 0 as both parameters attempt to solve the same problem (too much MP subtask activation/deactivation) and using both can reduce throughput or response times.

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