Managing server space for objects - Revision history

ELowell at 17:24, 25 May 2017

2017-05-25T17:24:33Z

← Older revision		Revision as of 17:24, 25 May 2017
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			==Overview==
	The <var class="product">Model 204</var> VTBL table is particularly impacted by		The <var class="product">Model 204</var> VTBL table is particularly impacted by
	<var class="product">SOUL</var> objects.		<var class="product">SOUL</var> objects.

JAL: misc cleanup

2016-05-24T18:53:21Z

misc cleanup

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ELowell: deleted
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2016-05-24T17:26:58Z

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← Older revision		Revision as of 17:26, 24 May 2016
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	<p>		<p>
	The request produces the default allocation for <var>Stringlists</var>: </p>		The request produces the default allocation for <var>Stringlists</var>: </p>
	<p class="code">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 3/18/0, count/pages swapped 21/21		<p class="code" style="font-size:80%">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 3/18/0, count/pages swapped 21/21
	COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, ~~<br />~~count/pages swapped 0/0		COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, count/pages swapped 0/0
	</p>		</p>

	With a <var>Sirius MaxObjects</var> setting that is sufficiently high (say, 25),		With a <var>Sirius MaxObjects</var> setting that is sufficiently high (say, 25),
	the compiler allocates object instance slots (6) according to its "Native" algorithm:		the compiler allocates object instance slots (6) according to its "Native" algorithm:
	<p class="code">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 6/35/0, count/pages swapped 18/18		<p class="code" style="font-size:80%">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 6/35/0, count/pages swapped 18/18
	COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, ~~<br />~~count/pages swapped 0/0		COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, count/pages swapped 0/0
	</p>		</p>
	<p>		<p>

ELowell: /* How the compiler options interact */

2016-05-24T17:13:03Z

How the compiler options interact

← Older revision		Revision as of 17:13, 24 May 2016
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	</ol>		</ol>

			[[File:cfiggg3a.png\|border\|center\|500px]]
	[[File:cfiggg3a.~~gif~~\|border\|center]]
	<p class="caption">Object allocation (multiple directives, Min < Max)</p>		<p class="caption">Object allocation (multiple directives, Min < Max)</p>
	<p>		<p>

ELowell: /* How the compiler options interact */

2016-05-24T17:04:43Z

How the compiler options interact

← Older revision		Revision as of 17:04, 24 May 2016
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	The request produces the default allocation for <var>Stringlists</var>: </p>		The request produces the default allocation for <var>Stringlists</var>: </p>
	<p class="code">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 3/18/0, count/pages swapped 21/21		<p class="code">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 3/18/0, count/pages swapped 21/21
	COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, count/pages swapped 0/0		COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, <br />count/pages swapped 0/0
	</p>		</p>

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	the compiler allocates object instance slots (6) according to its "Native" algorithm:		the compiler allocates object instance slots (6) according to its "Native" algorithm:
	<p class="code">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 6/35/0, count/pages swapped 18/18		<p class="code">OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 6/35/0, count/pages swapped 18/18
	COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, count/pages swapped 0/0		COLLECTION SYSTEM:ARRAYLIST OF OBJECT SYSTEM:STRINGLIST: objects/VTBL/STBL - 2/17/0, <br />count/pages swapped 0/0
	</p>		</p>
	<p>		<p>

JAL: /* Using compiler directives to modify object allocation */

2013-10-22T18:10:17Z

Using compiler directives to modify object allocation

← Older revision		Revision as of 18:10, 22 October 2013
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	For details about the calculation of the space allocated for an object,		For details about the calculation of the space allocated for an object,
	see the description of the components of the object statistics		see the description of the components of the object statistics
	in [[#Message format\|"Message format"]].		in [[#Message format\|Message format]].

	Contrast the default allocation behavior		Contrast the default allocation behavior
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	<tr><th><i>option</i>		<tr><th><i>option</i>
	</th><td>One of the following:		</th><td>One of the following:
	<table>		<table class="thJustBold">
	<tr><th>MaxObjects </th>		<tr><th>MaxObjects </th>
	<td>Sets an upper limit on the number of ''class'' objects for which space is allocated in VTBL/STBL. <code>Sirius MaxObjects</code> is useful for restraining server table size, although in some circumstances it can allow a larger allocation than if it were not specified. (For a demonstration of this paradoxical behavior, see the request example in		<td>Sets an upper limit on the number of ''class'' objects for which space is allocated in VTBL/STBL. <code>Sirius MaxObjects</code> is useful for restraining server table size, although in some circumstances it can allow a larger allocation than if it were not specified. (For a demonstration of this paradoxical behavior, see the request example in
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	may allocate — it allows but does not force a greater allocation		may allocate — it allows but does not force a greater allocation
	(as <code>Sirius MinObjects</code> does).		(as <code>Sirius MinObjects</code> does).

	<li>As shown in [[#A MinObjects example\|the next section]],		<li>As shown in [[#A MinObjects example\|the next section]],
	the <var>OBJSTAT</var> statistics report lets you compare object allocation and swapping		the <var>OBJSTAT</var> statistics report lets you compare object allocation and swapping
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	command output to indicate the effect on CPU performance of your adjustments.		command output to indicate the effect on CPU performance of your adjustments.
	</ul>		</ul>

	===A MinObjects example===		===A MinObjects example===
	To see the effects of the compiler directives,		To see the effects of the compiler directives,
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	If multiple directives are specified in a program for a class, this section describes rules for calculating the actual		If multiple directives are specified in a program for a class, this section describes rules for calculating the actual
	number of object instance slots for which the compiler allocates VTBL/STBL space.		number of object instance slots for which the compiler allocates VTBL/STBL space.
	<br>'''Note:'''		<p class="note">'''Note:'''
	Remember that the number of object instance slots for which the compiler		Remember that the number of object instance slots for which the compiler
	allocates space may not be optimal in terms of swapping reduction.		allocates space may not be optimal in terms of swapping reduction.
	It may not be an amount that eliminates swapping. Or it may be an amount that eliminates swapping, but is not		It may not be an amount that eliminates swapping. Or it may be an amount that eliminates swapping, but is not
	the lowest number of slots at which swapping is eliminated.		the lowest number of slots at which swapping is eliminated. </p>

	These are identifiers for the critical values taken into consideration in the rules that follow:		These are identifiers for the critical values taken into consideration in the rules that follow:
	<table>		<table class="thJustBold">
	<tr><th>AbMin		<tr><th>AbMin
	</th><td>Per class, the required minimum number of object instances for which space must be allocated in any request. This value overrides any and all explicit directives: the compiler will in all circumstances allocate at least <code>AbMin</code> object slots.		</th><td>Per class, the required minimum number of object instances for which space must be allocated in any request. This value overrides any and all explicit directives: the compiler will in all circumstances allocate at least <code>AbMin</code> object slots.
	</td></tr>		</td></tr>

	<tr><th>Max		<tr><th>Max
	</th><td>The effective <var>MaxObjects</var> value. Per class, the lowest <var>Sirius MaxObjects</var> setting.		</th><td>The effective <var>MaxObjects</var> value. Per class, the lowest <var>Sirius MaxObjects</var> setting.
	</td></tr>		</td></tr>

	<tr><th>Add		<tr><th>Add
	</th><td>The effective <var>AddObjects</var> value. Per class, the sum of the <var>Sirius AddObjects</var> settings.		</th><td>The effective <var>AddObjects</var> value. Per class, the sum of the <var>Sirius AddObjects</var> settings.
	</td></tr>		</td></tr>

	<tr><th>Min		<tr><th>Min
	</th><td>The effective <var>MinObjects</var> value. Per class, the larger of these: <ul> <li><code>AbMin</code> <li>The highest <var>Sirius MinObjects</var> setting, plus <code>Add</code>. </ul>		</th><td>The effective <var>MinObjects</var> value. Per class, the larger of these: <ul> <li><code>AbMin</code> <li>The highest <var>Sirius MinObjects</var> setting, plus <code>Add</code>. </ul>
	</td></tr>		</td></tr>

	<tr><th>Native		<tr><th>Native
	</th><td>The object instance allocation count determined by the compiler before consideration of any explicit or implied directives. This count is typically very close to the number of object variable declarations in the program.		</th><td>The object instance allocation count determined by the compiler before consideration of any explicit or implied directives. This count is typically very close to the number of object variable declarations in the program.
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	<li>The number of object slots allocated for a class		<li>The number of object slots allocated for a class
	is '''never''' allowed to fall below <code>AbMin</code> for that class.		is '''never''' allowed to fall below <code>AbMin</code> for that class.

	<li>The number of object slots allocated for a class is '''not'''		<li>The number of object slots allocated for a class is '''not'''
	allowed to exceed <code>Max</code> for that class.		allowed to exceed <code>Max</code> for that class.
	The only exception is if <code>Max</code> is less than <code>AbMin</code>.		The only exception is if <code>Max</code> is less than <code>AbMin</code>.

	<li>In the absence of any <var>MaxObjects</var> settings, <code>Min</code> becomes the		<li>In the absence of any <var>MaxObjects</var> settings, <code>Min</code> becomes the
	effective <code>Max</code>.		effective <code>Max</code>.

	<li>If there is a combination of <var>Sirius MaxObjects</var> and <var>Sirius MinObjects</var> specification for a class, the		<li>If there is a combination of <var>Sirius MaxObjects</var> and <var>Sirius MinObjects</var> specification for a class, the
	compiler allocates as follows:		compiler allocates as follows:
	<table>		<table>
	<tr><th>Situation		<tr class="head"><th>Situation
	</th><th>Object slots allocated		</th><th>Object slots allocated
	</th></tr>		</th></tr>

JAL at 18:04, 22 October 2013

2013-10-22T18:04:28Z

JAL: /* See also */

2013-10-14T22:14:41Z

JALWiccan: Automatically generated page update

2013-10-14T20:05:27Z

Automatically generated page update

← Older revision		Revision as of 20:05, 14 October 2013
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	[[Category:Overviews]]		[[Category:Overviews]]
	[[Category:~~Janus SOAP ULI~~ topics]]		[[Category:SOUL object-oriented programming topics]]

JALWiccan: Automatically generated page update

2013-06-03T21:29:04Z

Automatically generated page update

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	<li>[[Copying objects]]		<li>[[Copying objects]]
	<li>[[Global and session objects]]		<li>[[Global and session objects]]
	<li>[[Janus SOAP essentials]]		<li>[[Janus SOAP ULI essentials]]
	</ul>		</ul>

	[[Category:Overviews]]		[[Category:Overviews]]
	[[Category:Janus SOAP ULI topics]]		[[Category:Janus SOAP ULI topics]]

← Older revision		Revision as of 18:04, 22 October 2013
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	The <var class="product">Model 204</var> VTBL table is particularly impacted by		The <var class="product">Model 204</var> VTBL table is particularly impacted by
	<var class="product">~~[[Janus SOAP User Language Interface\|Janus SOAP ULI]]~~</var> objects.		<var class="product">SOUL</var> objects.
	VTBL space is required to accommodate two generic datastructures:		VTBL space is required to accommodate two generic datastructures:
	object references and object instances.		object references and object instances.
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	in parameters and in user method definitions), though they also may include		in parameters and in user method definitions), though they also may include
	some internal "work" object variables.		some internal "work" object variables.
	Object references are more complicated than <var class="product">~~User Language~~</var>		Object references are more complicated than <var class="product">SOUL</var>
	%variables, and they take a few times more space in VTBL.		%variables, and they take a few times more space in VTBL.

	<li>Object instances, which are completely run-time products,		<li>Object instances, which are completely run-time products,
	are created by a class's [[Object variables#Using New or other Constructors\|constructor]]		are created by a class's [[Object variables#Using New or other Constructors\|constructor]]
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	</ul>		</ul>

	<var class="product">~~Janus SOAP ULI~~</var> uses object swapping to handle cases where		<var class="product">SOUL</var> uses object swapping to handle cases where
	a request has more objects than the compiler has reserved VTBL/STBL space for.		a request has more objects than the compiler has reserved VTBL/STBL space for.
	Object swapping involves the managing of server-resident slots —		Object swapping involves the managing of server-resident slots —
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	once the code that uses those object classes is considered.		once the code that uses those object classes is considered.

	The subsections that follow discuss <var class="product">~~Janus SOAP ULI~~</var> object swapping,		The subsections that follow discuss <var class="product">SOUL</var> object swapping,
	the compiler directives		the compiler directives
	that let you exchange object swaps for server table space,		that let you exchange object swaps for server table space,
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	<li>[[#Displaying object statistics\|Displaying object statistics]]		<li>[[#Displaying object statistics\|Displaying object statistics]]
	</ul>		</ul>

	==Swapping objects==		==Swapping objects==
	<var class="product">~~Janus SOAP ULI~~</var> objects effectively live in VTBL (and STBL) ''and'' in CCATEMP.		<var class="product">SOUL</var> objects effectively live in VTBL (and STBL) ''and'' in CCATEMP.
	The compiler reserves VTBL/STBL space for only a few object instances		The compiler reserves VTBL/STBL space for only a few object instances
	for each class that is referenced in a request.		for each class that is referenced in a request.
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	[[Object variables#Discarding implicitly\|implicitly]].		[[Object variables#Discarding implicitly\|implicitly]].

	The <var class="product">~~Janus SOAP ULI~~</var> swapping scheme trades performance (CPU) for server size economy.		The <var class="product">SOUL</var> swapping scheme trades performance (CPU) for server size economy.
	In general, as swapping increases, performance slips.		In general, as swapping increases, performance slips.
	Decreasing the server size (number of object spaces allocated) means more		Decreasing the server size (number of object spaces allocated) means more
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	Because there is no right number of objects		Because there is no right number of objects
	to allocate at compile time, the <var class="product">~~User Language~~</var> compiler directives, discussed below,		to allocate at compile time, the <var class="product">SOUL</var> compiler directives, discussed below,
	are provided to allow a programmer who is more		are provided to allow a programmer who is more
	aware of the likely performance requirements of a class to set the		aware of the likely performance requirements of a class to set the
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	The <var>MaxObjects</var>, <var>MinObjects</var>,		The <var>MaxObjects</var>, <var>MinObjects</var>,
	and <var>AddObjects</var> options of the <var>Sirius</var> compiler directive		and <var>AddObjects</var> options of the <var>Sirius</var> compiler directive
	adjust the number of <var class="product">~~Janus SOAP ULI~~</var> objects for which VTBL/STBL space is allocated at		adjust the number of <var class="product">SOUL</var> objects for which VTBL/STBL space is allocated at
	request compile time.		request compile time.

	By default, that is, with no object compiler directives specified, <var class="product">~~Janus SOAP ULI~~</var>		By default, that is, with no object compiler directives specified, <var class="product">SOUL</var>
	allocates space for at most three (usually two) objects per class per request.		allocates space for at most three (usually two) objects per class per request.
	This ensures that only a small amount of server table space is used for objects,		This ensures that only a small amount of server table space is used for objects,
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	<p>		<p>
	This sets an upper limit on the number of objects for which space is allocated in VTBL/STBL.		This sets an upper limit on the number of objects for which space is allocated in VTBL/STBL.
	However, the space-conservative behavior of the default <var class="product">~~Janus SOAP ULI~~</var> object space		However, the space-conservative behavior of the default <var class="product">SOUL</var> object space
	allocation makes <code>Sirius MaxObjects</code> of limited utility.		allocation makes <code>Sirius MaxObjects</code> of limited utility.
	It may be most useful in a large program that liberally employs		It may be most useful in a large program that liberally employs
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	allocated as in this example would have broken the program because of		allocated as in this example would have broken the program because of
	insufficient VTBL space.		insufficient VTBL space.

	<li>The CPU savings were not dramatic:		<li>The CPU savings were not dramatic:
	<var class="product">~~Janus SOAP ULI~~</var> object swapping is quite efficient.		<var class="product">SOUL</var> object swapping is quite efficient.
	The savings are likely to be proportional to the size of the objects		The savings are likely to be proportional to the size of the objects
	that no longer are being swapped.		that no longer are being swapped.

	<li>The settings of the compiler directives were determined after a few trials.		<li>The settings of the compiler directives were determined after a few trials.
	Such testing is necessary because the effect of the setting of a directive		Such testing is necessary because the effect of the setting of a directive
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	by including user method definitions only if the methods are actually called.		by including user method definitions only if the methods are actually called.

	~~The~~ <var class="product">~~Janus SOAP ULI~~</var> classes incorporate a "header file" type of design:		<var class="product">SOUL</var> classes incorporate a "header file" type of design:
	the declaration of		the declaration of
	classes is distinct from the code that implements the classes.		classes is distinct from the code that implements the classes.
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	or method code within a single compilation of a complex program.		or method code within a single compilation of a complex program.
	You can even programmatically prevent such duplicate includes		You can even programmatically prevent such duplicate includes
	by using the <var>[[!DUPEXIT]]</var> <var class="product">~~User Language~~</var> macro.		by using the <var>[[!DUPEXIT]]</var> <var class="product">SOUL</var> macro.

	==Displaying object statistics==		==Displaying object statistics==
	The <var>OBJSTAT</var> User 0 parameter controls the display of journal messages that contain user statistics about <var class="product">~~Janus SOAP ULI~~</var> object usage per request. The messages specify server table usage (VTBL and STBL) and object-swapping counts per object class and summed for all classes.		The <var>OBJSTAT</var> User 0 parameter controls the display of journal messages that contain user statistics about <var class="product">SOUL</var> object usage per request. The messages specify server table usage (VTBL and STBL) and object-swapping counts per object class and summed for all classes.

	===Message format===		===Message format===

← Older revision		Revision as of 22:14, 14 October 2013
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	<li>[[Copying objects]]		<li>[[Copying objects]]
	<li>[[Global and session objects]]		<li>[[Global and session objects]]
	<li>[[~~Janus SOAP ULI essentials~~]]		<li>[[Object oriented programming in SOUL]]
	</ul>		</ul>

	[[Category:Overviews]]		[[Category:Overviews]]
	[[Category:SOUL object-oriented programming topics]]		[[Category:SOUL object-oriented programming topics]]

Managing server space for objects - Revision history

ELowell at 17:24, 25 May 2017

JAL: misc cleanup

ELowell: deleted from 2 msgs; instead reduced font size so they wouldn't overlap page margin

ELowell: /* How the compiler options interact */

ELowell: /* How the compiler options interact */

JAL: /* Using compiler directives to modify object allocation */

JAL at 18:04, 22 October 2013

JAL: /* See also */

JALWiccan: Automatically generated page update

JALWiccan: Automatically generated page update

ELowell: deleted
from 2 msgs; instead reduced font size so they wouldn't overlap page margin