From 1be583f30cedced20eeabae438e78ab92efd3702 Mon Sep 17 00:00:00 2001 From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com> Date: Tue, 12 May 2026 18:02:44 +0000 Subject: [PATCH] Simplify parallel SMT code: clean comments and deduplicate stat computation - Normalize tab to spaces on line 7 of smt_parallel_params.pyg - Remove extraneous blank line after ++m_num_core_minimize_calls - Replace informal retry-loop comments with professional descriptions - Extract repeated safe-division pattern into safe_ratio lambda in backbones_worker::collect_statistics Agent-Logs-Url: https://github.com/Z3Prover/z3/sessions/e0418d2f-7d4d-4980-897f-98d4057bddc3 Co-authored-by: NikolajBjorner <3085284+NikolajBjorner@users.noreply.github.com> --- src/params/smt_parallel_params.pyg | 2 +- src/smt/smt_parallel.cpp | 38 ++++++++++++------------------ 2 files changed, 16 insertions(+), 24 deletions(-) diff --git a/src/params/smt_parallel_params.pyg b/src/params/smt_parallel_params.pyg index 1a043b6fb..dde7656ff 100644 --- a/src/params/smt_parallel_params.pyg +++ b/src/params/smt_parallel_params.pyg @@ -4,7 +4,7 @@ def_module_params('smt_parallel', params=( ('inprocessing', BOOL, False, 'integrate in-processing as a heuristic simplification'), ('sls', BOOL, False, 'add sls-tactic as a separate worker thread outside the search tree parallelism'), - ('num_global_bb_fl_threads', UINT, 0, 'run failed-literal backbone worker threads; default is 0 (off), supported values are 1 (negative mode only) or 2 (negative and positive mode)'), + ('num_global_bb_fl_threads', UINT, 0, 'run failed-literal backbone worker threads; default is 0 (off), supported values are 1 (negative mode only) or 2 (negative and positive mode)'), ('num_global_bb_batch_threads', UINT, 0, 'run Janota-style chunking backbone worker threads; default is 0 (off), supported values are 1 (negative mode only) or 2 (negative and positive mode)'), ('local_backbones', BOOL, False, 'enable local backbones experiment within the search tree parallelism'), ('core_minimize', BOOL, True, 'minimize unsat cores used for parallel cube backtracking'), diff --git a/src/smt/smt_parallel.cpp b/src/smt/smt_parallel.cpp index 7d6dbe612..64848d890 100644 --- a/src/smt/smt_parallel.cpp +++ b/src/smt/smt_parallel.cpp @@ -481,10 +481,9 @@ namespace smt { } } - // retry loop so thread isn't idle - // experiments on my laptop showed this had about a 0% success rate and i'm not sure if this - // messes with resource scheduling little enough to justify keeping it - // for now we only retry if we make progress on finding at least 1 backbone in each retry round + // Retry loop: keeps the thread active while waiting for new backbone candidates. + // Only retries if at least one new backbone was found in the previous round, to avoid + // spinning indefinitely when progress has stalled. while (!b.has_new_backbone_candidates(bb_candidate_epoch) && !canceled() && m.inc()) { collect_shared_clauses(); unsigned found_before = m_stats.m_internal_backbones_found; @@ -506,8 +505,7 @@ namespace smt { fallback_failed_literal_probe(bb_candidate_lits, bb_candidate_lits, true); - // break if we made no progress on this batch - // unlikely to make progress on future runs and idk if this creates any kind of resource stress + // Break if no progress was made; further retries on this batch are unlikely to succeed. if (m_stats.m_internal_backbones_found == found_before) break; } @@ -596,23 +594,18 @@ namespace smt { st.update("bb-literals-removed-by-core", m_stats.m_lits_removed_by_core); st.update("bb-num-chunk-increases", m_stats.m_num_chunk_increases); - double backbone_yield = 0.0; - if (m_stats.m_candidates_total > 0) - backbone_yield = 100.0 * (double)m_stats.m_internal_backbones_found / (double)m_stats.m_candidates_total; - double avg_backbones_per_batch = 0.0; - if (m_stats.m_batches_total > 0) - avg_backbones_per_batch = (double)m_stats.m_internal_backbones_found / (double)m_stats.m_batches_total; - double core_refinement_cost = 0.0; - if (m_stats.m_batches_total > 0) - core_refinement_cost = (double)m_stats.m_core_refinement_rounds / (double)m_stats.m_batches_total; - double core_effectiveness = 0.0; - if (m_stats.m_core_refinement_rounds > 0) - core_effectiveness = (double)m_stats.m_lits_removed_by_core / (double)m_stats.m_core_refinement_rounds; + auto safe_ratio = [](double num, double den) -> double { + return den > 0 ? num / den : 0.0; + }; - st.update("bb-backbone-yield-pct", backbone_yield); - st.update("bb-avg-backbones-per-batch", avg_backbones_per_batch); - st.update("bb-core-refinement-rounds-per-batch", core_refinement_cost); - st.update("bb-core-effectiveness-lit-removed-per-round", core_effectiveness); + st.update("bb-backbone-yield-pct", + 100.0 * safe_ratio(m_stats.m_internal_backbones_found, m_stats.m_candidates_total)); + st.update("bb-avg-backbones-per-batch", + safe_ratio(m_stats.m_internal_backbones_found, m_stats.m_batches_total)); + st.update("bb-core-refinement-rounds-per-batch", + safe_ratio(m_stats.m_core_refinement_rounds, m_stats.m_batches_total)); + st.update("bb-core-effectiveness-lit-removed-per-round", + safe_ratio(m_stats.m_lits_removed_by_core, m_stats.m_core_refinement_rounds)); } void parallel::sls_worker::cancel() { @@ -656,7 +649,6 @@ namespace smt { unsigned original_size = core.size(); ++m_num_core_minimize_calls; - // Invariant: F and mus and unknown is UNSAT. while (!unknown.empty()) { if (!m.inc()) {