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dido:public:ra:xapend:xapend.f_qos:resource_linits [2021/06/12 16:52]
char
dido:public:ra:xapend:xapend.f_qos:resource_linits [2021/10/03 23:31] (current)
66.249.69.246 ↷ Links adapted because of a move operation
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 ====== F.19 Resource Limits ​ ====== ====== F.19 Resource Limits ​ ======
-[[dido:​public:​ra:​xapend:​xapend.f_qos| Return to DDS Quality of Service ]]+[[dido:​public:​ra:​xapend:​xapend.f_qos:start| Return to DDS Quality of Service ]] 
 + 
 +The RESOURCE_LIMITS [[dido:​public:​ra:​xapend:​xapend.a_glossary:​p:​policy|policy]] controls the resources that the Service can use in order to meet the requirements imposed by the [[dido:​public:​ra:​xapend:​xapend.a_glossary:​a:​application|application]] and other [[dido:​public:​ra:​xapend:​xapend.a_glossary:​q:​qos|QoS]] settings. 
 + 
 +If the ''​DataWriter''​ objects are communicating [[dido:​public:​ra:​xapend:​xapend.a_glossary:​s:​sample|samples]] faster than they are ultimately taken by the ''​DataReader''​ objects, the [[dido:​public:​ra:​xapend:​xapend.a_glossary:​m:​midware|middleware]] will eventually hit against some of the QoS-imposed resource limits. Note that this may occur when just a single ''​DataReader''​ cannot keep up with its corresponding ''​DataWriter''​. The behavior in this case depends on the setting for the RELIABILITY QoS. If reliability is BEST_EFFORT then the Service is allowed to drop samples. If the reliability is RELIABLE, the Service will block the ''​DataWriter''​ or discard the sample at the ''​DataReader''​ 28in order not to loose existing samples. 
 + 
 +The constant LENGTH_UNLIMITED may be used to indicate the absence of a particular limit. For example setting ''​max_samples_per_instance''​ to ''​LENGH_UNLIMITED''​ will cause the middleware to not enforce this particular limit. 
 + 
 +The setting of RESOURCE_LIMITS ''​max_samples''​ must be consistent with the ''​max_samples_per_instance''​. For these two values to be consistent they must verify that ''​max_samples >= max_samples_per_instance''"​. 
 + 
 +The setting of RESOURCE_LIMITS max_samples_per_instance must be consistent with the [[dido:​public:​ra:​xapend:​xapend.a_glossary:​h:​history_qos|HISTORY]] ''​depth''​. For these two QoS to be consistent, they must verify that''​depth <= max_samples_per_instance''"​. 
 + 
 +An attempt to set this policy to inconsistent values when an [[dido:​public:​ra:​xapend:​xapend.a_glossary:​e:​entity|entity]] is created of via a ''​set_qos''​ operation will cause the operation to fail. 
 + 
 + 
 +Source: [[https://​www.omg.org/​spec/​DDS/​1.4/​PDF | DDS 1.4 Spec]] 
 + 
 +/​**=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- 
 +/* To add a discussion page to this page, comment out the line that says  
 +  ~~DISCUSSION:​off~~ 
 +*/ 
 +~~DISCUSSION:​on|Outstanding Issues~~ 
 +~~DISCUSSION:​off~~
  
-  : <wrap hi><​color blue>To Be Completed</​color></​wrap>​ 
dido/public/ra/xapend/xapend.f_qos/resource_linits.1623531128.txt.gz · Last modified: 2021/06/12 16:52 by char