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-rw-r--r--TAO/orbsvcs/orbsvcs/LoadBalancing/LB_LeastLoaded.cpp641
1 files changed, 0 insertions, 641 deletions
diff --git a/TAO/orbsvcs/orbsvcs/LoadBalancing/LB_LeastLoaded.cpp b/TAO/orbsvcs/orbsvcs/LoadBalancing/LB_LeastLoaded.cpp
deleted file mode 100644
index 00c4fa6203d..00000000000
--- a/TAO/orbsvcs/orbsvcs/LoadBalancing/LB_LeastLoaded.cpp
+++ /dev/null
@@ -1,641 +0,0 @@
-#include "orbsvcs/LoadBalancing/LB_LeastLoaded.h"
-#include "orbsvcs/LoadBalancing/LB_LoadMap.h"
-#include "orbsvcs/LoadBalancing/LB_Random.h"
-
-#include "orbsvcs/PortableGroup/PG_conf.h"
-
-#include "tao/debug.h"
-#include "tao/ORB_Constants.h"
-
-#include "ace/Null_Mutex.h"
-#include "ace/OS_NS_string.h"
-
-
-ACE_RCSID (LoadBalancing,
- LB_LeastLoaded,
- "$Id$")
-
-
-#if !defined (__ACE_INLINE__)
-#include "orbsvcs/LoadBalancing/LB_LeastLoaded.inl"
-#endif /* defined INLINE */
-
-TAO_BEGIN_VERSIONED_NAMESPACE_DECL
-
-TAO_LB_LeastLoaded::TAO_LB_LeastLoaded (PortableServer::POA_ptr poa)
- : poa_ (PortableServer::POA::_duplicate (poa)),
- load_map_ (0),
- lock_ (0),
- properties_ (),
- critical_threshold_ (TAO_LB::LL_DEFAULT_CRITICAL_THRESHOLD),
- reject_threshold_ (TAO_LB::LL_DEFAULT_REJECT_THRESHOLD),
- tolerance_ (TAO_LB::LL_DEFAULT_TOLERANCE),
- dampening_ (TAO_LB::LL_DEFAULT_DAMPENING),
- per_balance_load_ (TAO_LB::LL_DEFAULT_DAMPENING)
-{
- // A load map that retains previous load values at a given location
- // and lock are only needed if dampening is enabled, i.e. non-zero.
- if (this->dampening_ != 0)
- {
- ACE_NEW (this->load_map_, TAO_LB_LoadMap (TAO_PG_MAX_LOCATIONS));
-
- ACE_NEW (this->lock_, TAO_SYNCH_MUTEX);
- }
-
- // Initialize the random load balancing strategy.
- TAO_LB_Random::init ();
-}
-
-TAO_LB_LeastLoaded::~TAO_LB_LeastLoaded (void)
-{
- delete this->load_map_;
- delete this->lock_;
-}
-
-char *
-TAO_LB_LeastLoaded::name (ACE_ENV_SINGLE_ARG_DECL_NOT_USED)
- ACE_THROW_SPEC ((CORBA::SystemException))
-{
- return CORBA::string_dup ("LeastLoaded");
-}
-
-CosLoadBalancing::Properties *
-TAO_LB_LeastLoaded::get_properties (ACE_ENV_SINGLE_ARG_DECL)
- ACE_THROW_SPEC ((CORBA::SystemException))
-{
- CosLoadBalancing::Properties * props = 0;
- ACE_NEW_THROW_EX (props,
- CosLoadBalancing::Properties (this->properties_),
- CORBA::NO_MEMORY (
- CORBA::SystemException::_tao_minor_code (
- TAO::VMCID,
- ENOMEM),
- CORBA::COMPLETED_NO));
- ACE_CHECK_RETURN (0);
-
- return props;
-}
-
-void
-TAO_LB_LeastLoaded::push_loads (
- const PortableGroup::Location & the_location,
- const CosLoadBalancing::LoadList & loads
- ACE_ENV_ARG_DECL)
- ACE_THROW_SPEC ((CORBA::SystemException))
-{
- // Only the first load is used by this load balancing strategy.
- if (loads.length () == 0)
- ACE_THROW (CORBA::BAD_PARAM ());
-
- CosLoadBalancing::Load load; // Unused
-
- this->push_loads (the_location,
- loads,
- load
- ACE_ENV_ARG_PARAMETER);
-}
-
-void
-TAO_LB_LeastLoaded::push_loads (
- const PortableGroup::Location & the_location,
- const CosLoadBalancing::LoadList & loads,
- CosLoadBalancing::Load & load
- ACE_ENV_ARG_DECL)
-{
- if (loads.length () == 0)
- ACE_THROW (CORBA::BAD_PARAM ());
-
- // Only the first load is used by this load balancing strategy.
- const CosLoadBalancing::Load & new_load = loads[0];
-
- if (this->load_map_ != 0)
- {
- ACE_GUARD (TAO_SYNCH_MUTEX, guard, *this->lock_);
-
- TAO_LB_LoadMap::ENTRY * entry;
- if (this->load_map_->find (the_location, entry) == 0)
- {
- CosLoadBalancing::Load & previous_load = entry->int_id_;
-
- if (previous_load.id != new_load.id)
- ACE_THROW (CORBA::BAD_PARAM ()); // Somebody switched
- // LoadIds on us!
-
- previous_load.value =
- this->effective_load (previous_load.value, new_load.value);
-
- load = previous_load;
- }
- else
- {
- const CosLoadBalancing::Load eff_load =
- {
- new_load.id,
- this->effective_load (0, new_load.value)
- };
-
- if (this->load_map_->bind (the_location, eff_load) != 0)
- {
- if (TAO_debug_level > 0)
- ACE_ERROR ((LM_ERROR,
- "ERROR: TAO_LB_LeastLoaded - "
- "Unable to push loads\n"));
-
- ACE_THROW (CORBA::INTERNAL ());
- }
-
- load = eff_load;
- }
- }
- else
- {
- load.id = new_load.id;
- load.value = this->effective_load (0, new_load.value);
- }
-}
-
-CosLoadBalancing::LoadList *
-TAO_LB_LeastLoaded::get_loads (CosLoadBalancing::LoadManager_ptr load_manager,
- const PortableGroup::Location & the_location
- ACE_ENV_ARG_DECL)
- ACE_THROW_SPEC ((CORBA::SystemException,
- CosLoadBalancing::LocationNotFound))
-{
- if (CORBA::is_nil (load_manager))
- ACE_THROW_RETURN (CORBA::BAD_PARAM (), 0);
-
- CosLoadBalancing::LoadList_var loads =
- load_manager->get_loads (the_location
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK_RETURN (0);
-
- this->push_loads (the_location,
- loads.in (),
- loads[0]
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK_RETURN (0);
-
- return loads._retn ();
-}
-
-
-CORBA::Object_ptr
-TAO_LB_LeastLoaded::next_member (
- PortableGroup::ObjectGroup_ptr object_group,
- CosLoadBalancing::LoadManager_ptr load_manager
- ACE_ENV_ARG_DECL)
- ACE_THROW_SPEC ((CORBA::SystemException,
- PortableGroup::ObjectGroupNotFound,
- PortableGroup::MemberNotFound))
-{
- if (CORBA::is_nil (load_manager))
- ACE_THROW_RETURN (CORBA::BAD_PARAM (),
- CORBA::Object::_nil ());
-
- PortableGroup::Locations_var locations =
- load_manager->locations_of_members (object_group
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK_RETURN (CORBA::Object::_nil ());
-
- if (locations->length () == 0)
- ACE_THROW_RETURN (CORBA::TRANSIENT (),
- CORBA::Object::_nil ());
-
- // @@ RACE CONDITION. OBJECT GROUP MEMBERSHIP MAY CHANGE AFTER
- // RETRIEVING LOCATIONS! HOW DO WE HANDLE THAT?
-
- PortableGroup::Location location;
- CORBA::Boolean found_location =
- this->get_location (load_manager,
- locations.in (),
- location
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK_RETURN (CORBA::Object::_nil ());
-
- if (found_location)
- {
-// ACE_DEBUG ((LM_DEBUG,
-// "RETURNING REFERENCE FOR LOCATION \"%s\"\n",
-// location[0].id.in ()));
-
- return load_manager->get_member_ref (object_group,
- location
- ACE_ENV_ARG_PARAMETER);
- }
- else
- {
- // No loads have been reported for any of the locations the
- // object group members reside at. If no loads have been
- // reported to the LoadManager, adaptive load balancing
- // decisions cannot be made. Fall back on a non-adaptive
- // strategy, such as the Random load balancing strategy,
- // instead.
- //
- // @note The Random load balancing strategy is used since it is
- // very lightweight and stateless.
-
- return TAO_LB_Random::_tao_next_member (object_group,
- load_manager,
- locations.in ()
- ACE_ENV_ARG_PARAMETER);
- }
-}
-
-void
-TAO_LB_LeastLoaded::analyze_loads (
- PortableGroup::ObjectGroup_ptr object_group,
- CosLoadBalancing::LoadManager_ptr load_manager
- ACE_ENV_ARG_DECL)
- ACE_THROW_SPEC ((CORBA::SystemException))
-{
- if (CORBA::is_nil (load_manager))
- ACE_THROW (CORBA::BAD_PARAM ());
-
- PortableGroup::Locations_var locations =
- load_manager->locations_of_members (object_group
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK;
-
- if (locations->length () == 0)
- ACE_THROW (CORBA::TRANSIENT ());
-
- const CORBA::ULong len = locations->length ();
-
- // Iterate through the entire location list to determine which
- // locations require load to be shed.
- for (CORBA::ULong i = 0; i < len; ++i)
- {
- ACE_TRY
- {
- const PortableGroup::Location & loc = locations[i];
-
- // Retrieve the load list for the location from the
- // LoadManager and push it to this Strategy's load
- // processor.
- CosLoadBalancing::LoadList_var current_loads =
- load_manager->get_loads (loc
- ACE_ENV_ARG_PARAMETER);
- ACE_TRY_CHECK;
-
- CosLoadBalancing::Load load;
- this->push_loads (loc,
- current_loads.in (),
- load
- ACE_ENV_ARG_PARAMETER);
- ACE_TRY_CHECK;
-/*
- ACE_DEBUG ((LM_DEBUG,
- "EFFECTIVE_LOAD == %f\n"
- "CRITICAL == %f\n"
- "REJECT == %f\n"
- "DAMPENING == %f\n",
- load.value,
- this->critical_threshold_,
- this->reject_threshold_,
- this->dampening_));
-*/
- // Perform load rebalancing only if the critical threshold
- // was set.
- if (this->critical_threshold_ != 0)
- {
- if (load.value > this->critical_threshold_)
- {
-/*
- ACE_DEBUG ((LM_DEBUG,
- "%P --- ALERTING LOCATION %u\n",
- i));
-*/
-
- // The location is overloaded. Perform load
- // shedding by informing the LoadAlert object
- // associated with the member at that location it
- // should redirect client requests back to the
- // LoadManager.
- load_manager->enable_alert (loc
- ACE_ENV_ARG_PARAMETER);
- ACE_TRY_CHECK;
- }
- else
- {
- // The location is not overloaded. Disable load
- // shedding at given location.
- load_manager->disable_alert (loc
- ACE_ENV_ARG_PARAMETER);
- ACE_TRY_CHECK;
- }
- }
- }
- ACE_CATCH (CosLoadBalancing::LocationNotFound, ex)
- {
- // No load available for the requested location. Try the
- // next location.
- }
- ACE_ENDTRY;
- ACE_CHECK;
- }
-}
-
-PortableServer::POA_ptr
-TAO_LB_LeastLoaded::_default_POA (ACE_ENV_SINGLE_ARG_DECL_NOT_USED)
-{
- return PortableServer::POA::_duplicate (this->poa_.in ());
-}
-
-CORBA::Boolean
-TAO_LB_LeastLoaded::get_location (
- CosLoadBalancing::LoadManager_ptr load_manager,
- const PortableGroup::Locations & locations,
- PortableGroup::Location & location
- ACE_ENV_ARG_DECL)
-{
- CORBA::Float min_load = FLT_MAX; // Start out with the largest
- // positive value.
-
- CORBA::ULong location_index = 0;
- CORBA::Boolean found_location = 0;
- CORBA::Boolean found_load = 0;
-
- const CORBA::ULong len = locations.length ();
-
- // Iterate through the entire location list to find the least loaded
- // of them.
- for (CORBA::ULong i = 0; i < len; ++i)
- {
- ACE_TRY
- {
- const PortableGroup::Location & loc = locations[i];
-
- // Retrieve the load list for the location from the LoadManager
- // and push it to this Strategy's load processor.
- CosLoadBalancing::LoadList_var current_loads =
- load_manager->get_loads (loc
- ACE_ENV_ARG_PARAMETER);
- ACE_TRY_CHECK;
-
- found_load = 1;
-
- CosLoadBalancing::Load load;
- this->push_loads (loc,
- current_loads.in (),
- load
- ACE_ENV_ARG_PARAMETER);
- ACE_TRY_CHECK;
-/*
- ACE_DEBUG ((LM_DEBUG,
- "LOC = %u"
- "\tC = %d"
- "\treject = %f"
- "\tload = %f\n"
- "\tmin_load = %f\n",
- i,
- (this->reject_threshold_ == 0
- || load.value < this->reject_threshold_),
- this->reject_threshold_,
- load.value,
- min_load));
-*/
- if ((this->reject_threshold_ == 0
- || load.value < this->reject_threshold_)
- && load.value < min_load)
- {
-// ACE_DEBUG ((LM_DEBUG,
-// "**** LOAD == %f\n",
-// load.value));
-
- if (i > 0 && load.value != 0)
- {
- /*
- percent difference =
- (min_load - load.value) / load.value
- == (min_load / load.value) - 1
-
- The latter form is used to avoid a potential
- arithmetic overflow problem, such as when
- (min_load - load.value) > FLT_MAX, assuming that
- either load.value is negative and min_load is
- positive, or vice versa.
- */
- const CORBA::Float percent_diff =
- (min_load / load.value) - 1;
-
- /*
- A "thundering herd" phenomenon may occur when
- location loads are basically the same (e.g. only
- differ by a very small amount), where one object
- group member ends up receiving the majority of
- requests from different clients. In order to
- prevent a single object group member from
- receiving such request bursts, one of two equally
- loaded locations is chosen at random. Thanks to
- Carlos, Marina and Jody at ATD for coming up with
- this solution to this form of the thundering herd
- problem.
-
- See the documentation for
- TAO_LB::LL_DEFAULT_LOAD_PERCENT_DIFF_CUTOFF in
- LB_LeastLoaded.h for additional information.
- */
- if (percent_diff <= TAO_LB::LL_DEFAULT_LOAD_PERCENT_DIFF_CUTOFF)
- {
- // Prevent integer arithmetic overflow.
- const CORBA::Float NUM_MEMBERS = 2;
-
- // n == 0: Use previously selected location.
- // n == 1: Use current location.
- const CORBA::ULong n =
- static_cast<CORBA::ULong> (NUM_MEMBERS * ACE_OS::rand ()
- / (RAND_MAX + 1.0));
-
- ACE_ASSERT (n == 0 || n == 1);
-
- if (n == 1)
- {
- min_load = load.value;
- location_index = i;
- found_location = 1;
-
-// ACE_DEBUG ((LM_DEBUG,
-// "** NEW MIN_LOAD == %f\n",
-// min_load));
- }
-
-// if (n == 0)
-// ACE_DEBUG ((LM_DEBUG, "^^^^^ PREVIOUS LOCATION\n"));
-// else
-// ACE_DEBUG ((LM_DEBUG, "^^^^^ CURRENT LOCATION\n"));
-
- }
- else
- {
- min_load = load.value;
- location_index = i;
- found_location = 1;
-
-// ACE_DEBUG ((LM_DEBUG,
-// "***** NEW MIN_LOAD == %f\n",
-// min_load));
- }
- }
- else
- {
- min_load = load.value;
- location_index = i;
- found_location = 1;
-
-// ACE_DEBUG ((LM_DEBUG,
-// "NEW MIN_LOAD == %f\n",
-// min_load));
- }
- }
-
- // ACE_DEBUG ((LM_DEBUG, "NEW MIN_LOAD == %f\n", min_load));
- }
- ACE_CATCH (CosLoadBalancing::LocationNotFound, ex)
- {
- // No load available for the requested location. Try the
- // next location.
- }
- ACE_ENDTRY;
- ACE_CHECK_RETURN (0);
- }
-
-// ACE_DEBUG ((LM_DEBUG,
-// "FOUND_LOAD == %u\n"
-// "FOUND_LOCATION == %u\n",
-// found_load,
-// found_location));
-
- // If no loads were found, return without an exception to allow this
- // strategy to select a member using an alternative method
- // (e.g. random selection).
- if (found_load)
- {
- if (found_location)
- {
- //ACE_DEBUG ((LM_DEBUG, "LOCATED = %u\n", location_index));
- location = locations[location_index];
- }
- else if (this->reject_threshold_ != 0)
- ACE_THROW_RETURN (CORBA::TRANSIENT (), 0);
-
-// ACE_DEBUG ((LM_DEBUG, "LOCATION ID == %s\n", location[0].id.in ()));
- }
-
- return found_location;
-}
-
-void
-TAO_LB_LeastLoaded::init (const PortableGroup::Properties & props
- ACE_ENV_ARG_DECL)
-{
- CORBA::Float critical_threshold =
- TAO_LB::LL_DEFAULT_CRITICAL_THRESHOLD;
- CORBA::Float reject_threshold = TAO_LB::LL_DEFAULT_REJECT_THRESHOLD;
- CORBA::Float tolerance = TAO_LB::LL_DEFAULT_TOLERANCE;
- CORBA::Float dampening = TAO_LB::LL_DEFAULT_DAMPENING;
- CORBA::Float per_balance_load = TAO_LB::LL_DEFAULT_PER_BALANCE_LOAD;
-
- const PortableGroup::Property * ct = 0; // critical threshold property
-
- const CORBA::ULong len = props.length ();
- for (CORBA::ULong i = 0; i < len; ++i)
- {
- const PortableGroup::Property & property = props[i];
- if (ACE_OS::strcmp (property.nam[0].id.in (),
- "org.omg.CosLoadBalancing.Strategy.LeastLoaded.CriticalThreshold") == 0)
- {
- this->extract_float_property (property,
- critical_threshold
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK;
-
- ct = &property;
- }
-
- else if (ACE_OS::strcmp (property.nam[0].id.in (),
- "org.omg.CosLoadBalancing.Strategy.LeastLoaded.RejectThreshold") == 0)
- {
- this->extract_float_property (property,
- reject_threshold
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK;
- }
-
- else if (ACE_OS::strcmp (property.nam[0].id.in (),
- "org.omg.CosLoadBalancing.Strategy.LeastLoaded.Tolerance") == 0)
- {
- this->extract_float_property (property,
- tolerance
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK;
-
- // Valid tolerance values are greater than or equal to one.
- if (tolerance < 1)
- ACE_THROW (PortableGroup::InvalidProperty (property.nam,
- property.val));
- }
-
- else if (ACE_OS::strcmp (property.nam[0].id.in (),
- "org.omg.CosLoadBalancing.Strategy.LeastLoaded.Dampening") == 0)
- {
- this->extract_float_property (property,
- dampening
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK;
-
- // Dampening range is [0,1).
- if (dampening < 0 || dampening >= 1)
- ACE_THROW (PortableGroup::InvalidProperty (property.nam,
- property.val));
- }
-
- else if (ACE_OS::strcmp (property.nam[0].id.in (),
- "org.omg.CosLoadBalancing.Strategy.LeastLoaded.PerBalanceLoad") == 0)
- {
- this->extract_float_property (property,
- per_balance_load
- ACE_ENV_ARG_PARAMETER);
- ACE_CHECK;
- }
- }
-
- if (critical_threshold != 0 && reject_threshold != 0
- && critical_threshold <= reject_threshold)
- ACE_THROW (PortableGroup::InvalidProperty (ct->nam, ct->val));
-
- this->properties_ = props;
-
- this->critical_threshold_ = critical_threshold;
- this->reject_threshold_ = reject_threshold;
- this->tolerance_ = tolerance;
- this->dampening_ = dampening;
- this->per_balance_load_ = per_balance_load;
-/*
- ACE_DEBUG ((LM_DEBUG,
- "--------------------------------\n"
- "critical_threshold = %f\n"
- "reject_threshold = %f\n"
- "tolerance = %f\n"
- "dampening = %f\n"
- "per_balance_load = %f\n"
- "--------------------------------\n",
- critical_threshold,
- reject_threshold,
- tolerance,
- dampening,
- per_balance_load));
-*/
-}
-
-void
-TAO_LB_LeastLoaded::extract_float_property (
- const PortableGroup::Property & property,
- CORBA::Float & value
- ACE_ENV_ARG_DECL)
-{
- if (!(property.val >>= value))
- ACE_THROW (PortableGroup::InvalidProperty (property.nam,
- property.val));
-}
-
-TAO_END_VERSIONED_NAMESPACE_DECL
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