205 lines
12 KiB
Plaintext
205 lines
12 KiB
Plaintext
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// -*- C++ -*-
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namespace Kite {
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/*! \page pageNotes Notes
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*
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* \section Summary
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*
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* - \ref ssecVariousNotes "Various Things to Remeber"
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* - \ref secPendingModifications "Pending Modifications"
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* - \ref secModificationsHistory "Modifications History"
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* - \ref ssecArchitectureChanges "Changes in the general architecture"
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* - \ref ssecModificationsKiteEngine "Changes in KiteEngine class design"
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* - \ref ssecModificationsDataNegociate "Changes in DataNegociate class design"
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* - \ref ssecModificationsTrackElement "Changes in TrackElement class design"
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* - \ref ssecModificationsTrackSegment "Changes in TrackSegment class design"
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* - \ref ssecModificationsAutoSegment "Changes in AutoSegment class design"
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* - \ref ssecModificationsAutoContact "Changes in AutoContact class design"
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* - \ref ssecBugBusting "Bug Solving Memento"
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* - \ref ssecNanoRoute "Evaluation with Cadence NanoRoute"
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*
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* \section ssecVariousNotes Various Things to Remember
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*
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* - <b>Determinism checking.</b> The trace level to get only determinism related
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* log is \c 500. Each line for the determinism is prepended with 'Deter|',
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* possible with some leading spaces.
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*
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* - The router only sees/manages the aligned segment sets (through a pseudo-
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* decorator on their canonical segment). So the non-canonical segments
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* and the contacts should not be handled at all at this level.
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* - Do do confuse the Session::Event, events that modificate
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* the state of the Kite database (insert, move or remove TrackSegment
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* in Track) and the RoutingEvent class which request that a segment
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* must be processed.
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* - In the various processing method of RoutingEvent, when a TrackSegment
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* can be inserted inside a Track a Session::Event is generated but
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* no further RoutingEvent, this end the placement processus of
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* segment (until it is ripped-up).
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* - AutoSegment do not invalidate their S/T anchor contacts.
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* - AutoContact invalidate their anchored upon AutoSegment.
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* - Now that the Hurricane database is deterministic, the router
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* seems to be likewise.
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*
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* - <b>Reduce/raise mechanism</b>. To manage <em>same layer</em> dogleg
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* this mechanism has been implemented. When a candidate dogleg
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* perpandicular segment length shrink below one pitch it is
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* removed from any track to become <em>invisible</em>.
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* Conversely, when a reduced segment length expand over one pitch
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* generate a new RoutingEvent to insert it. All this is managed
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* in the Session::revalidate() method.
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*
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*
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* \section secPendingModifications Pending Modifications
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*
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* - In SegmentAction::doAction(), completly disable the movement of
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* TrackSegment on it's target Track axis. This should not be
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* needed as, if the algorithm as worked correctly, the next time
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* it's RoutingEvent is processed, the target Track will have a
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* free space to insert into. Then the Track insertion will
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* set the TrackSegment axis.
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* - Has to complete the lazy evaluation of the TrackSegment / DataNegociate
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* / RoutingEvent. There is still some redundancy when the key of
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* the RoutingEvent is updated.
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* - In AutoContact::updateTopology() & AutoContact::updateGeometry()
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* we could avoid to systematically run through the Hooks to cache
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* the connected segments. This can be done once at the first call
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* of either method (whichever comes first) on the first revalidate.
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* Afterwards the cache can be updated only by AutoContact::updateTopology().
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* - The canonization is done in two places, directly on a set of aligneds
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* AutoSegments through AutoSegment::canonize() and for the whole net
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* Session::_canonize(), which is called after the initial creation and
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* each time the topology is modificated. The later may be suppressed
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* if we uses more intelligently the former, and gain some more speedup.
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*
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*
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* \section secModificationsHistory Modifications History
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*
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* \subsection ssecArchitectureChanges Changes in the general architecture
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*
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* - <b>Lazy Update.</b> Update of DataNegociate and RoutingEvent
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* are now delayed until the event is processed, and systematically
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* done at this point. Thus, the explicit invalidation of those
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* objects is no longer needed. The revalidation is no longer
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* triggered by the revalidation of TrackSegment.
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*
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*
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* \subsection ssecModificationsKiteEngine Changes in KiteEngine class design
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*
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* - Suppress the lookup table of Hurricane::Segment toward
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* TrackSegment. Instead uses the Observer mecanism between
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* Katabatic::AutoSegment and TrackSegment.
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*
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*
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* \subsection ssecModificationsDataNegociate Changes in DataNegociate class design
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*
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* - Merge in the separate class \c Cost.
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* - Suppress the \c SlackState::Desalignate, due to the simplificated
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* structure of the AutoSegment/AutoContacts (no more collapseds, or
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* forced alignements).
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* - Displace the computation and caching of the perpandiculars and
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* perpandicular free interval from RoutingEvent into DataNegociate.
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* Allows code factorization with the attractors computation, and
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* data size reduction as there is exaclty one DataNegociate but
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* there may be more than one RoutingEvent for the same TrackSegment.
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*
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*
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* \subsection ssecModificationsTrackElement Changes in TrackElement class design
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*
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* - Due to the simplificated structure of the Katabatic contacts
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* (terminal, turn, vtee & htee), there's no longer collapsed
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* AutoSegment or \e expandable contacts. The \b desalignate
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* feature, relaxing constraints due to collapsed segments
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* or contacts with more than three segments, is no longer
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* implemented.
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* \redB{Have to redevelop a method to break long segments linked}
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* \redB{by HTee or VTee.}
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*
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*
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* \subsection ssecModificationsTrackSegment Changes in TrackSegment class design
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*
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* - The method \c TrackSegment::_postModify() is merged with
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* TrackSegment::_postDoglegs() as, in the context of TrackSegment
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* the only used topological modifications goes through the creation
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* of one or more dogleg.
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*
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*
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* \subsection ssecModificationsAutoSegment Changes in AutoSegment class design
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*
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* - In AutoSegment::_makeDogleg(), update the local/global status
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* of the involved AutoSegment and re-canonize only what is necessary.
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* Thus, guarantee that the net's topology is still valid after this
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* method call and no topological update is needed at Session level
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* (should be \e much faster).
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* In this method, the code sharing between AutoHorizontal and
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* AutoVertical can still be increased (update mechanisms are
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* identicals).
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* - The \c id support is now also implemented at Hurricane level.
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* We may choose to use as a replacement of the one already present
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* in AutoSegment. But in that case, we at least must cache the
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* id in the AutoSegment. So we will not gain in memory footprint,
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* the only benefit would be to have coherent id number throughout
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* all the tools, but the sequentiality will be lost (this may not
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* be a big issue).
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*
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*
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* \subsection ssecModificationsAutoContact Changes in AutoContact class design
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*
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* - In AutoSegment::invalidate(), no longer uses collection to
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* walk through attached AutoSegment, directly uses the cache.
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* Much simple and efficient as we exactly know what is attached
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* on every kind of contact.
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*
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*
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* \section ssecBugBusting Bug Solving Memento
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*
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* <b>LUT lookup change:</b> When breaking a TrackSegment, the break may
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* not occurs in the associated canonical AutoSegment. In that case the
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* <code>dogleg[O]</code> will not match the one that is looked up
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* for the broken (canonical) segment. Thus it was not a bug but a
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* misunderstanding...
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*
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* <b>Overlap of perpandiculars after a dogleg creation:</b>
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* The axis of the new parallel was not set to the axis of it's parent.
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* This was due to the uses of AutoSegment::setAxis() in
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* AutoHorizontal::_makeDogleg() which silently
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* do nothing on non-canonical AutoSegment, and at this point, the
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* re-canonisation did not yet take place. Now Uses AutoSegment::_setAxis()
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* the atomic variant wich works inconditionnaly.
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*
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*
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* \section ssecNanoRoute Evaluation with Cadence NanoRoute
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*
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* To perform a comparison with NanoRoute the procedure is as follow:
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*
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* - Export the design in Alliance \c DEF format. It will generate both
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* \c DEF file and the supporting \c LEF file containing the technology
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* and the abstract of all the standard cell of the design.
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* As Alliance uses symbolic units (lambda), they are translated with
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* the simple rule: <b>1 lambda == 1 micron</b>.
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*
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* - Run the commands in NanoRoute:
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* - <tt>loadLefFile design.lef</tt>
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* - <tt>loadDefFile design.def</tt>
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* - <tt>generateTracks</tt>
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* - <tt>generateVias</tt>
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* - <tt>setNanoRouteMode -quiet -drouteFixAntenna 0</tt>
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* - <tt>setNanoRouteMode -quiet -drouteStartIteration default</tt>
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* - <tt>setNanoRouteMode -quiet -routeTopRoutingLayer default</tt>
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* - <tt>setNanoRouteMode -quiet -routeBottomRoutingLayer 2</tt>
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* - <tt>setNanoRouteMode -quiet -drouteEndIteration default</tt>
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* - <tt>setNanoRouteMode -quiet -routeWithTimingDriven false</tt>
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* - <tt>setNanoRouteMode -quiet -routeWithSiDriven false</tt>
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* - <tt>routeDesign -globalDetail</tt>
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*
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* - To perform as fair a comparison as possible, those commands disable
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* antenna effect protection and disable the use of the \c M1 as a
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* routing layer (<tt>-routeBottomRoutingLayer 2</tt>). Those commands
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* are issued through the graphical interface of NanoRoute.
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*
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* <em>To see the resulting layout, do not forget to switch the view mode.</em>
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*/
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}
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