Internals: Refactor MT scheduling (#8012)

mirror of https://github.com/verilator/verilator.git synced 2026-08-30 01:38:21 +02:00

Prep for fixing test added in #7913.

This is a large scale no functional change refactor, however, MT output
is perturbed as tied scores will be broken differently due to ordering
changes (still deterministic).

Split multi-threaded scheduling out of the monolithic
V3OrderParallel.cpp, into relatively independent parts, simplify the
data structures, and drop redundant or unused code.

New translation units:
- V3OrderMTaskGraph.h/.cpp: OrderMTaskGraph, the graph of LogicMTask
  vertices and MTaskEdge edges. LogicMTask and MTaskEdge no longer
  depend on the coarsening algorithm's merge candidate types;
  per-algorithm auxiliary data is attached externally via the vertex and
  edge user pointers.
- V3OrderMTaskFixHazards.cpp: data hazard fixup, was FixDataHazards.
- V3OrderMTaskContraction.cpp: graph coarsening, was Partitioner
  together with PropagateCp and the merge candidate types.
- V3OrderParallel.cpp: now just the partitioning driver and ExecMTask
  graph construction.

Data structure changes:
- Delete V3Scoreboard.h/.cpp. The generic template had a single user, now
  a file-local MergeCandidateScoreboard in V3OrderMTaskContraction.cpp.
- Merge candidates are now MergeCandidate/SiblingMC/EdgeMC, distinguished
  by a bit in the candidate id rather than by a vtable, and allocated by
  the scoreboard, which owns their lifetime. This removes the multiple
  inheritance previously used by MTaskEdge.

Move `hashGraphDebug` which prints the hash of a graph's shape for debugging
to generic `V3Graph::hashGraphDebug`.

Removed (can be added back later):
- Unnecesasry self tests that force special data stucture requirements.
- Per stage --stats output under --debug. (Final figures still reported.)
- Various debug dumps

This commit is contained in:

Geza Lore

2026-07-31 15:03:26 +01:00

committed by

GitHub

parent 40323cc02c

commit 781f6d90bf

19 changed files with 2400 additions and 2597 deletions

									
										src/Verilator.cpp
									
		-3
	
												View File
												
				@@ -96,7 +96,6 @@

				#include "V3Sampled.h"

				#include "V3Sched.h"

				#include "V3Scope.h"

				#include "V3Scoreboard.h"

				#include "V3Slice.h"

				#include "V3Split.h"

				#include "V3SplitVar.h"

				@@ -744,8 +743,6 @@ static bool verilate(const string& argString) {

				        VHashSha256::selfTest();

				        VSpellCheck::selfTest();

				        V3Graph::selfTest();

				        V3ScoreboardBase::selfTest();

				        V3Order::selfTestParallel();

				        V3ExecGraph::selfTest();

				        V3PreShell::selfTest();

				        V3Broken::selfTest();