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attempt at lease policy patch

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This commit is contained in:
Ilana Shapiro 2026-06-15 23:14:53 -07:00
parent fc5e4d7557
commit c10e7c2a6f
4 changed files with 38 additions and 68 deletions
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24
src/smt/smt_parallel.cpp
View file

@ -559,7 +559,7 @@ namespace smt {
if (m_ablate_backtracking) { if (m_ablate_backtracking) {
// Ablation: for each target, pass the entire path from root to that node // Ablation: for each target, pass the entire path from root to that node
for (auto const& target : targets) { for (auto const& target : targets) {
if (m_search_tree.is_lease_canceled(target.leased_node, target.cancel_epoch)) if (m_search_tree.is_lease_canceled(target.leased_node))
continue; continue;
// Reconstruct the full path from root to this target node // Reconstruct the full path from root to this target node
@ -1135,7 +1135,7 @@ namespace smt {
// only cancel workers that currently hold a lease, whose lease is canceled, // only cancel workers that currently hold a lease, whose lease is canceled,
// and haven't already been signaled (prevents multiple inc_cancel() for same lease) // and haven't already been signaled (prevents multiple inc_cancel() for same lease)
if (lease.leased_node && !lease.cancel_signaled && m_search_tree.is_lease_canceled(lease.leased_node, lease.cancel_epoch)) { if (lease.leased_node && !lease.cancel_signaled && m_search_tree.is_lease_canceled(lease.leased_node)) {
p.m_workers[worker_id]->cancel_lease(); p.m_workers[worker_id]->cancel_lease();
m_worker_leases[worker_id].cancel_signaled = true; m_worker_leases[worker_id].cancel_signaled = true;
} }
@ -1190,14 +1190,13 @@ namespace smt {
unsigned best_idx = select_best_core_min_job_unlocked(); unsigned best_idx = select_best_core_min_job_unlocked();
m_core_min_jobs.swap(best_idx, m_core_min_jobs.size() - 1); m_core_min_jobs.swap(best_idx, m_core_min_jobs.size() - 1);
core_min_job* job = m_core_min_jobs.detach_back(); scoped_ptr<core_min_job> job = m_core_min_jobs.detach_back();
m_core_min_jobs.pop_back(); m_core_min_jobs.pop_back();
SASSERT(job); SASSERT(job);
source = job->source; source = job->source;
core.reset(); core.reset();
for (expr* c : job->core) for (expr* c : job->core)
core.push_back(g2l(c)); core.push_back(g2l(c));
dealloc(job);
return source != nullptr; return source != nullptr;
} }
@ -1288,7 +1287,7 @@ namespace smt {
if (!g_core.empty()) { if (!g_core.empty()) {
collect_matching_targets_unlocked(source, g_core[0].get(), g_core, targets); collect_matching_targets_unlocked(source, g_core[0].get(), g_core, targets);
for (auto const& target : targets) { for (auto const& target : targets) {
if (!m_search_tree.is_lease_canceled(target.leased_node, target.cancel_epoch)) if (!m_search_tree.is_lease_canceled(target.leased_node))
m_search_tree.backtrack(target.leased_node, g_core); m_search_tree.backtrack(target.leased_node, g_core);
} }
} }
@ -1342,7 +1341,7 @@ namespace smt {
for (node* t : matches) { for (node* t : matches) {
if (!t || t == source) if (!t || t == source)
continue; continue;
if (m_search_tree.is_lease_canceled(t, t->get_cancel_epoch())) if (m_search_tree.is_lease_canceled(t))
continue; continue;
// When source is provided, keep only external matches. Nodes in the // When source is provided, keep only external matches. Nodes in the
@ -1369,7 +1368,7 @@ namespace smt {
if (!is_highest_ancestor) if (!is_highest_ancestor)
continue; continue;
targets.push_back({ t, t->get_cancel_epoch() }); targets.push_back({ t });
} }
} }
@ -1385,7 +1384,7 @@ namespace smt {
SASSERT(lease != nullptr || targets != nullptr); SASSERT(lease != nullptr || targets != nullptr);
bool did_backtrack = false; bool did_backtrack = false;
if (lease && !m_search_tree.is_lease_canceled(lease->leased_node, lease->cancel_epoch)) { if (lease && !m_search_tree.is_lease_canceled(lease->leased_node)) {
// we close/backtrack regardless of whether this lease is stale or not, as long as the lease isn't canceled // we close/backtrack regardless of whether this lease is stale or not, as long as the lease isn't canceled
// i.e. worker 1 splits this node, but then worker 2 determines UNSAT --> worker 2 is stale but we still close this node and backtrack // i.e. worker 1 splits this node, but then worker 2 determines UNSAT --> worker 2 is stale but we still close this node and backtrack
did_backtrack = true; did_backtrack = true;
@ -1395,7 +1394,7 @@ namespace smt {
} }
if (targets) { if (targets) {
for (auto const& target : *targets) { for (auto const& target : *targets) {
if (m_search_tree.is_lease_canceled(target.leased_node, target.cancel_epoch)) if (m_search_tree.is_lease_canceled(target.leased_node))
continue; continue;
did_backtrack = true; did_backtrack = true;
@ -1427,13 +1426,13 @@ namespace smt {
if (m_state != state::is_running) if (m_state != state::is_running)
return; return;
if (m_search_tree.is_lease_canceled(lease.leased_node, lease.cancel_epoch)) if (m_search_tree.is_lease_canceled(lease.leased_node))
return; return;
expr_ref lit(m), nlit(m); expr_ref lit(m), nlit(m);
lit = l2g(atom); lit = l2g(atom);
nlit = mk_not(m, lit); nlit = mk_not(m, lit);
bool did_split = m_search_tree.try_split(lease.leased_node, lease.cancel_epoch, lit, nlit, effort); bool did_split = m_search_tree.try_split(lease.leased_node, lit, nlit, effort);
release_lease_unlocked(worker_id, lease.leased_node); release_lease_unlocked(worker_id, lease.leased_node);
@ -1451,7 +1450,7 @@ namespace smt {
bool parallel::batch_manager::lease_canceled(node_lease const &lease) { bool parallel::batch_manager::lease_canceled(node_lease const &lease) {
std::scoped_lock lock(mux); std::scoped_lock lock(mux);
return m_state == state::is_running && m_search_tree.is_lease_canceled(lease.leased_node, lease.cancel_epoch); return m_state == state::is_running && m_search_tree.is_lease_canceled(lease.leased_node);
} }
void parallel::batch_manager::collect_clause(ast_translation &l2g, unsigned source_worker_id, expr *clause) { void parallel::batch_manager::collect_clause(ast_translation &l2g, unsigned source_worker_id, expr *clause) {
@ -1763,7 +1762,6 @@ namespace smt {
IF_VERBOSE(2, m_search_tree.display(verbose_stream()); verbose_stream() << "\n";); IF_VERBOSE(2, m_search_tree.display(verbose_stream()); verbose_stream() << "\n";);
lease.leased_node = t; lease.leased_node = t;
lease.cancel_epoch = t->get_cancel_epoch();
if (id >= m_worker_leases.size()) if (id >= m_worker_leases.size())
m_worker_leases.resize(id + 1); m_worker_leases.resize(id + 1);
m_worker_leases[id] = lease; m_worker_leases[id] = lease;

6
src/smt/smt_parallel.h
View file

@ -64,12 +64,6 @@ namespace smt {
struct node_lease { struct node_lease {
node* leased_node = nullptr; node* leased_node = nullptr;
// Cancellation generation counter for this node/subtree.
// Incremented when the node is closed; used to signal that all
// workers holding leases on this node (or its descendants)
// must abandon work immediately.
unsigned cancel_epoch = 0;
// Guards against multiple inc_cancel() calls for the same lease. // Guards against multiple inc_cancel() calls for the same lease.
// Set when cancel_lease() is signaled; cleared when a new lease is assigned. // Set when cancel_lease() is signaled; cleared when a new lease is assigned.
bool cancel_signaled = false; bool cancel_signaled = false;

60
src/solver/parallel_tactical2.cpp
View file

@ -127,12 +127,6 @@ class parallel_solver {
struct node_lease { struct node_lease {
search_tree::node<solver_cube_config>* leased_node = nullptr; search_tree::node<solver_cube_config>* leased_node = nullptr;
// Cancellation generation counter for this node/subtree.
// Incremented when the node is closed; used to signal that all
// workers holding leases on this node (or its descendants)
// must abandon work immediately.
unsigned cancel_epoch = 0;
// Guards against multiple inc_cancel() calls for the same lease. // Guards against multiple inc_cancel() calls for the same lease.
// Set when cancel_lease() is signaled; cleared when a new lease is assigned. // Set when cancel_lease() is signaled; cleared when a new lease is assigned.
bool cancel_signaled = false; bool cancel_signaled = false;
@ -218,7 +212,7 @@ class parallel_solver {
expr_ref_vector m_unsat_core; expr_ref_vector m_unsat_core;
// called from batch manager to cancel other workers if we've reached a verdict // called from batch manager to cancel other workers if we've reached a verdict
void cancel_workers_unlocked() { void cancel_background_threads() {
IF_VERBOSE(1, verbose_stream() << "Canceling workers\n"); IF_VERBOSE(1, verbose_stream() << "Canceling workers\n");
for (auto* w : p.m_workers) for (auto* w : p.m_workers)
w->cancel(); w->cancel();
@ -248,7 +242,7 @@ class parallel_solver {
if (id == source_worker_id) continue; if (id == source_worker_id) continue;
auto const& lease = m_worker_leases[id]; auto const& lease = m_worker_leases[id];
if (lease.leased_node && !lease.cancel_signaled && if (lease.leased_node && !lease.cancel_signaled &&
m_search_tree.is_lease_canceled(lease.leased_node, lease.cancel_epoch)) { m_search_tree.is_lease_canceled(lease.leased_node)) {
p.m_workers[id]->cancel_lease(); p.m_workers[id]->cancel_lease();
m_worker_leases[id].cancel_signaled = true; m_worker_leases[id].cancel_signaled = true;
} }
@ -316,7 +310,7 @@ class parallel_solver {
for (auto* t : matches) { for (auto* t : matches) {
if (!t || t == source) if (!t || t == source)
continue; continue;
if (m_search_tree.is_lease_canceled(t, t->get_cancel_epoch())) if (m_search_tree.is_lease_canceled(t))
continue; continue;
// When source is provided, keep only external matches. Nodes in the // When source is provided, keep only external matches. Nodes in the
@ -343,7 +337,7 @@ class parallel_solver {
if (!is_highest_ancestor) if (!is_highest_ancestor)
continue; continue;
targets.push_back({ t, t->get_cancel_epoch() }); targets.push_back({ t });
} }
} }
@ -405,7 +399,7 @@ class parallel_solver {
SASSERT(lease != nullptr || targets != nullptr); SASSERT(lease != nullptr || targets != nullptr);
bool did_backtrack = false; bool did_backtrack = false;
if (lease && !m_search_tree.is_lease_canceled(lease->leased_node, lease->cancel_epoch)) { if (lease && !m_search_tree.is_lease_canceled(lease->leased_node)) {
// we close/backtrack regardless of whether this lease is stale or not, as long as the lease isn't canceled // we close/backtrack regardless of whether this lease is stale or not, as long as the lease isn't canceled
// i.e. worker 1 splits this node, but then worker 2 determines UNSAT --> worker 2 is stale but we still close this node and backtrack // i.e. worker 1 splits this node, but then worker 2 determines UNSAT --> worker 2 is stale but we still close this node and backtrack
did_backtrack = true; did_backtrack = true;
@ -414,7 +408,7 @@ class parallel_solver {
} }
if (targets) { if (targets) {
for (auto const& target : *targets) { for (auto const& target : *targets) {
if (m_search_tree.is_lease_canceled(target.leased_node, target.cancel_epoch)) if (m_search_tree.is_lease_canceled(target.leased_node))
continue; continue;
did_backtrack = true; did_backtrack = true;
m_search_tree.backtrack(target.leased_node, g_core); m_search_tree.backtrack(target.leased_node, g_core);
@ -438,7 +432,7 @@ class parallel_solver {
SASSERT(m_unsat_core.empty()); SASSERT(m_unsat_core.empty());
for (auto& e : m_search_tree.get_core_from_root()) for (auto& e : m_search_tree.get_core_from_root())
m_unsat_core.push_back(e.get()); m_unsat_core.push_back(e.get());
cancel_workers_unlocked(); cancel_background_threads();
} }
} }
@ -477,14 +471,14 @@ class parallel_solver {
if (m_state != state::is_running) return; if (m_state != state::is_running) return;
m_state = state::is_sat; m_state = state::is_sat;
m_model = mdl.translate(l2g); m_model = mdl.translate(l2g);
cancel_workers_unlocked(); cancel_background_threads();
} }
void set_cancel() { void set_cancel() {
std::scoped_lock lock(mux); std::scoped_lock lock(mux);
if (m_state != state::is_running) if (m_state != state::is_running)
return; return;
cancel_workers_unlocked(); cancel_background_threads();
} }
void set_unsat(ast_translation& l2g, void set_unsat(ast_translation& l2g,
@ -496,7 +490,7 @@ class parallel_solver {
SASSERT(m_unsat_core.empty()); SASSERT(m_unsat_core.empty());
for (expr* c : core) for (expr* c : core)
m_unsat_core.push_back(l2g(c)); m_unsat_core.push_back(l2g(c));
cancel_workers_unlocked(); cancel_background_threads();
} }
void set_exception(std::string const& msg) { void set_exception(std::string const& msg) {
@ -505,7 +499,7 @@ class parallel_solver {
if (m_state != state::is_running) return; if (m_state != state::is_running) return;
m_state = state::is_exception_msg; m_state = state::is_exception_msg;
m_exception_msg = msg; m_exception_msg = msg;
cancel_workers_unlocked(); cancel_background_threads();
} }
void set_exception(unsigned error_code) { void set_exception(unsigned error_code) {
@ -514,7 +508,7 @@ class parallel_solver {
if (m_state != state::is_running) return; if (m_state != state::is_running) return;
m_state = state::is_exception_code; m_state = state::is_exception_code;
m_exception_code = error_code; m_exception_code = error_code;
cancel_workers_unlocked(); cancel_background_threads();
} }
bool get_cube(ast_translation& g2l, unsigned id, bool get_cube(ast_translation& g2l, unsigned id,
@ -531,7 +525,6 @@ class parallel_solver {
if (!t) return false; if (!t) return false;
lease.leased_node = t; lease.leased_node = t;
lease.cancel_epoch = t->get_cancel_epoch();
if (id >= m_worker_leases.size()) if (id >= m_worker_leases.size())
m_worker_leases.resize(id + 1); m_worker_leases.resize(id + 1);
m_worker_leases[id] = lease; m_worker_leases[id] = lease;
@ -638,7 +631,7 @@ class parallel_solver {
m_unsat_core.push_back(l2g(e)); m_unsat_core.push_back(l2g(e));
++m_stats.m_core_min_jobs_published; ++m_stats.m_core_min_jobs_published;
++m_stats.m_core_min_global_unsat; ++m_stats.m_core_min_global_unsat;
cancel_workers_unlocked(); cancel_background_threads();
return; return;
} }
@ -651,7 +644,7 @@ class parallel_solver {
if (!g_core.empty()) { if (!g_core.empty()) {
collect_matching_targets_unlocked(source, g_core[0].get(), g_core, targets); collect_matching_targets_unlocked(source, g_core[0].get(), g_core, targets);
for (auto const& target : targets) { for (auto const& target : targets) {
if (!m_search_tree.is_lease_canceled(target.leased_node, target.cancel_epoch)) if (!m_search_tree.is_lease_canceled(target.leased_node))
m_search_tree.backtrack(target.leased_node, g_core); m_search_tree.backtrack(target.leased_node, g_core);
} }
} }
@ -672,7 +665,7 @@ class parallel_solver {
SASSERT(m_unsat_core.empty()); SASSERT(m_unsat_core.empty());
for (auto& e : m_search_tree.get_core_from_root()) for (auto& e : m_search_tree.get_core_from_root())
m_unsat_core.push_back(e.get()); m_unsat_core.push_back(e.get());
cancel_workers_unlocked(); cancel_background_threads();
} }
} }
@ -682,7 +675,7 @@ class parallel_solver {
return false; return false;
if (m_state != state::is_running) if (m_state != state::is_running)
return false; return false;
if (m_search_tree.is_lease_canceled(lease.leased_node, lease.cancel_epoch)) if (m_search_tree.is_lease_canceled(lease.leased_node))
return false; return false;
expr_ref _atom(l2g(atom), m); expr_ref _atom(l2g(atom), m);
@ -694,8 +687,7 @@ class parallel_solver {
expr* atom, unsigned effort) { expr* atom, unsigned effort) {
std::scoped_lock lock(mux); std::scoped_lock lock(mux);
if (m_state != state::is_running) return; if (m_state != state::is_running) return;
if (m_search_tree.is_lease_canceled( if (m_search_tree.is_lease_canceled(lease.leased_node)) return;
lease.leased_node, lease.cancel_epoch)) return;
expr_ref lit(m), nlit(m); expr_ref lit(m), nlit(m);
lit = l2g(atom); lit = l2g(atom);
@ -704,8 +696,7 @@ class parallel_solver {
VERIFY(!lease.leased_node->path_contains_atom(nlit)); VERIFY(!lease.leased_node->path_contains_atom(nlit));
bool did_split = m_search_tree.try_split( bool did_split = m_search_tree.try_split(
lease.leased_node, lease.cancel_epoch, lease.leased_node, lit, nlit, effort);
lit, nlit, effort);
release_lease_unlocked(worker_id, lease.leased_node); release_lease_unlocked(worker_id, lease.leased_node);
@ -726,8 +717,7 @@ class parallel_solver {
bool lease_canceled(node_lease const& lease) { bool lease_canceled(node_lease const& lease) {
std::scoped_lock lock(mux); std::scoped_lock lock(mux);
return m_state == state::is_running && return m_state == state::is_running &&
m_search_tree.is_lease_canceled( m_search_tree.is_lease_canceled(lease.leased_node);
lease.leased_node, lease.cancel_epoch);
} }
void collect_clause(ast_translation& l2g, void collect_clause(ast_translation& l2g,
@ -1630,8 +1620,6 @@ class parallel_solver {
curr_batch.reset(); curr_batch.reset();
} }
if (!m.inc())
b.set_cancel();
} }
public: public:
@ -1831,8 +1819,7 @@ class parallel_solver {
if (minimized.size() < original_size) if (minimized.size() < original_size)
b.publish_minimized_core(m_l2g, asms, source, original_size, minimized); b.publish_minimized_core(m_l2g, asms, source, original_size, minimized);
} }
if (!m.inc()) b.set_cancel();
b.set_cancel();
} }
void cancel() { void cancel() {
@ -1892,8 +1879,6 @@ public:
static_cast<unsigned>(std::thread::hardware_concurrency()), static_cast<unsigned>(std::thread::hardware_concurrency()),
pp.threads_max()); pp.threads_max());
bool core_minimize = pp.core_minimize(); bool core_minimize = pp.core_minimize();
if (pp.ablate_backtracking())
core_minimize = false;
unsigned num_bb_threads = pp.num_bb_threads(); unsigned num_bb_threads = pp.num_bb_threads();
if (num_bb_threads > 2) if (num_bb_threads > 2)
throw default_exception("parallel.num_bb_threads must be 0, 1, or 2"); throw default_exception("parallel.num_bb_threads must be 0, 1, or 2");
@ -1941,7 +1926,7 @@ public:
m_batch_manager.initialize(num_bb_threads); m_batch_manager.initialize(num_bb_threads);
auto safe_run = [&](std::function<void()> run_fn, reslimit& lim) { auto safe_run = [&](auto&& run_fn, reslimit& lim) {
try { try {
run_fn(); run_fn();
if (lim.is_canceled()) if (lim.is_canceled())
@ -1960,11 +1945,12 @@ public:
m_batch_manager.set_cancel(); m_batch_manager.set_cancel();
} }
}; };
/* Launch threads. */ /* Launch threads. */
vector<std::thread> threads; vector<std::thread> threads;
for (auto *w : m_workers) for (auto *w : m_workers)
threads.push_back(std::thread([w, &safe_run]() { threads.push_back(std::thread([w, &safe_run]() {
safe_run([w]() { w->run(); }, w->limit()); safe_run([w]() { w->run(); }, w->limit());
})); }));
if (m_core_minimizer_worker) if (m_core_minimizer_worker)
threads.push_back(std::thread([this, &safe_run]() { threads.push_back(std::thread([this, &safe_run]() {

16
src/util/search_tree.h
View file

@ -50,7 +50,6 @@ namespace search_tree {
unsigned m_effort_spent = 0; unsigned m_effort_spent = 0;
unsigned m_round_max_effort = 0; unsigned m_round_max_effort = 0;
unsigned m_active_workers = 0; unsigned m_active_workers = 0;
unsigned m_cancel_epoch = 0;
public: public:
node(literal const &l, node *parent) : m_literal(l), m_parent(parent), m_status(status::open) {} node(literal const &l, node *parent) : m_literal(l), m_parent(parent), m_status(status::open) {}
@ -156,12 +155,6 @@ namespace search_tree {
m_round_max_effort = effort; m_round_max_effort = effort;
m_effort_spent += m_round_max_effort; m_effort_spent += m_round_max_effort;
} }
unsigned get_cancel_epoch() const {
return m_cancel_epoch;
}
void inc_cancel_epoch() {
++m_cancel_epoch;
}
}; };
template <typename Config> class tree { template <typename Config> class tree {
@ -348,7 +341,6 @@ namespace search_tree {
void close(node<Config> *n, vector<literal> const &C) { void close(node<Config> *n, vector<literal> const &C) {
if (!n || n->get_status() == status::closed) if (!n || n->get_status() == status::closed)
return; return;
n->inc_cancel_epoch();
n->set_status(status::closed); n->set_status(status::closed);
n->set_core(C); n->set_core(C);
close(n->left(), C); close(n->left(), C);
@ -452,8 +444,8 @@ namespace search_tree {
// On timeout, either expand the current leaf or reopen the node for a // On timeout, either expand the current leaf or reopen the node for a
// later revisit, depending on the tree-expansion heuristic. // later revisit, depending on the tree-expansion heuristic.
bool try_split(node<Config> *n, unsigned cancel_epoch, literal const &a, literal const &b, unsigned effort) { bool try_split(node<Config> *n, literal const &a, literal const &b, unsigned effort) {
if (is_lease_canceled(n, cancel_epoch)) if (is_lease_canceled(n))
return false; return false;
// Record at most one effort contribution per concurrent round on this node. // Record at most one effort contribution per concurrent round on this node.
@ -552,8 +544,8 @@ namespace search_tree {
n->dec_active_workers(); n->dec_active_workers();
} }
bool is_lease_canceled(node<Config>* n, unsigned cancel_epoch) const { bool is_lease_canceled(node<Config>* n) const {
return !n || n->get_status() == status::closed || n->get_cancel_epoch() != cancel_epoch; return !n || n->get_status() == status::closed;
} }
vector<literal> const &get_core_from_root() const { vector<literal> const &get_core_from_root() const {