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Track the number of active elections by each bucket and cap at the bu…
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…cket maximum.

The number of elections started for a particular bucket is now limited on a per-bucket basis rather than globally across all buckets.
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@clemahieu
clemahieu committed May 15, 2024
1 parent 5448bfe commit 9c7d417
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Showing 12 changed files with 153 additions and 334 deletions.
109 changes: 6 additions & 103 deletions nano/core_test/active_elections.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -163,7 +163,7 @@ TEST (active_elections, keep_local)
nano::node_config node_config = system.default_config ();
node_config.enable_voting = false;
// Bound to 2, won't drop wallet created transactions, but good to test dropping remote
node_config.active_elections.size = 2;
node_config.priority_scheduler.bucket_maximum = 2;
// Disable frontier confirmation to allow the test to finish before
node_config.frontiers_confirmation = nano::frontiers_confirmation_mode::disabled;

Expand Down Expand Up @@ -192,7 +192,10 @@ TEST (active_elections, keep_local)
ASSERT_NE (nullptr, send6);

// force-confirm blocks
nano::test::confirm (node.ledger, send6);
auto election = nano::test::start_election (system, node, send6->hash ());
ASSERT_NE (nullptr, election);
election->force_confirm ();
ASSERT_TIMELY (5s, node.active.empty ());

nano::state_block_builder builder{};
const auto receive1 = builder.make_block ()
Expand Down Expand Up @@ -227,8 +230,7 @@ TEST (active_elections, keep_local)
node.process_active (receive3);

/// bound elections, should drop after one loop
ASSERT_TIMELY_EQ (5s, node.active.size (), node_config.active_elections.size);
// ASSERT_EQ (1, node.scheduler.size ());
ASSERT_TIMELY_EQ (5s, node.active.size (), node_config.priority_scheduler.bucket_maximum);
}

TEST (inactive_votes_cache, basic)
Expand Down Expand Up @@ -433,7 +435,6 @@ TEST (inactive_votes_cache, election_start)
nano::test::system system;
nano::node_config node_config = system.default_config ();
node_config.frontiers_confirmation = nano::frontiers_confirmation_mode::disabled;
node_config.priority_scheduler.enabled = false;
node_config.optimistic_scheduler.enabled = false;
auto & node = *system.add_node (node_config);
nano::block_hash latest (node.latest (nano::dev::genesis_key.pub));
Expand Down Expand Up @@ -1389,101 +1390,3 @@ TEST (active_elections, limit_vote_hinted_elections)
// Ensure there was no overflow of elections
ASSERT_EQ (0, node.stats.count (nano::stat::type::active_dropped, nano::stat::detail::priority));
}

/*
* Tests that when AEC is running at capacity from normal elections, it is still possible to schedule a limited number of hinted elections
*/
TEST (active_elections, allow_limited_overflow)
{
nano::test::system system;
nano::node_config config = system.default_config ();
const int aec_limit = 20;
config.frontiers_confirmation = nano::frontiers_confirmation_mode::disabled;
config.active_elections.size = aec_limit;
config.active_elections.hinted_limit_percentage = 20; // Should give us a limit of 4 hinted elections
auto & node = *system.add_node (config);

auto blocks = nano::test::setup_independent_blocks (system, node, aec_limit * 4);

// Split blocks in two halves
std::vector<std::shared_ptr<nano::block>> blocks1 (blocks.begin (), blocks.begin () + blocks.size () / 2);
std::vector<std::shared_ptr<nano::block>> blocks2 (blocks.begin () + blocks.size () / 2, blocks.end ());

// Even though automatic frontier confirmation is disabled, AEC is doing funny stuff and inserting elections, clear that
WAIT (1s);
node.active.clear ();
ASSERT_TRUE (node.active.empty ());

// Insert the first part of the blocks into normal election scheduler
for (auto const & block : blocks1)
{
node.scheduler.priority.activate (node.ledger.tx_begin_read (), block->account ());
}

// Ensure number of active elections reaches AEC limit and there is no overfill
ASSERT_TIMELY_EQ (5s, node.active.size (), node.active.limit (nano::election_behavior::priority));
// And it stays that way without increasing
ASSERT_ALWAYS (1s, node.active.size () == node.active.limit (nano::election_behavior::priority));

// Insert votes for the second part of the blocks, so that those are scheduled as hinted elections
for (auto const & block : blocks2)
{
// Non-final vote, so it stays in the AEC without getting confirmed
auto vote = nano::test::make_vote (nano::dev::genesis_key, { block });
node.vote_cache.insert (vote);
}

// Ensure active elections overfill AEC only up to normal + hinted limit
ASSERT_TIMELY_EQ (5s, node.active.size (), node.active.limit (nano::election_behavior::priority) + node.active.limit (nano::election_behavior::hinted));
// And it stays that way without increasing
ASSERT_ALWAYS (1s, node.active.size () == node.active.limit (nano::election_behavior::priority) + node.active.limit (nano::election_behavior::hinted));
}

/*
* Tests that when hinted elections are present in the AEC, normal scheduler adapts not to exceed the limit of all elections
*/
TEST (active_elections, allow_limited_overflow_adapt)
{
nano::test::system system;
nano::node_config config = system.default_config ();
const int aec_limit = 20;
config.frontiers_confirmation = nano::frontiers_confirmation_mode::disabled;
config.active_elections.size = aec_limit;
config.active_elections.hinted_limit_percentage = 20; // Should give us a limit of 4 hinted elections
auto & node = *system.add_node (config);

auto blocks = nano::test::setup_independent_blocks (system, node, aec_limit * 4);

// Split blocks in two halves
std::vector<std::shared_ptr<nano::block>> blocks1 (blocks.begin (), blocks.begin () + blocks.size () / 2);
std::vector<std::shared_ptr<nano::block>> blocks2 (blocks.begin () + blocks.size () / 2, blocks.end ());

// Even though automatic frontier confirmation is disabled, AEC is doing funny stuff and inserting elections, clear that
WAIT (1s);
node.active.clear ();
ASSERT_TRUE (node.active.empty ());

// Insert votes for the second part of the blocks, so that those are scheduled as hinted elections
for (auto const & block : blocks2)
{
// Non-final vote, so it stays in the AEC without getting confirmed
auto vote = nano::test::make_vote (nano::dev::genesis_key, { block });
node.vote_cache.insert (vote);
}

// Ensure hinted election amount is bounded by hinted limit
ASSERT_TIMELY_EQ (5s, node.active.size (), node.active.limit (nano::election_behavior::hinted));
// And it stays that way without increasing
ASSERT_ALWAYS (1s, node.active.size () == node.active.limit (nano::election_behavior::hinted));

// Insert the first part of the blocks into normal election scheduler
for (auto const & block : blocks1)
{
node.scheduler.priority.activate (node.ledger.tx_begin_read (), block->account ());
}

// Ensure number of active elections reaches AEC limit and there is no overfill
ASSERT_TIMELY_EQ (5s, node.active.size (), node.active.limit (nano::election_behavior::priority));
// And it stays that way without increasing
ASSERT_ALWAYS (1s, node.active.size () == node.active.limit (nano::election_behavior::priority));
}
93 changes: 0 additions & 93 deletions nano/core_test/election_scheduler.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -53,96 +53,3 @@ TEST (election_scheduler, activate_one_flush)
system.nodes[0]->scheduler.priority.activate (system.nodes[0]->ledger.tx_begin_read (), nano::dev::genesis_key.pub);
ASSERT_TIMELY (5s, system.nodes[0]->active.election (send1->qualified_root ()));
}

/**
* Tests that the election scheduler and the active transactions container (AEC)
* work in sync with regards to the node configuration value "active_elections.size".
*
* The test sets up two forcefully cemented blocks -- a send on the genesis account and a receive on a second account.
* It then creates two other blocks, each a successor to one of the previous two,
* and processes them locally (without the node starting elections for them, but just saving them to disk).
*
* Elections for these latter two (B1 and B2) are started by the test code manually via `election_scheduler::activate`.
* The test expects E1 to start right off and take its seat into the AEC.
* E2 is expected not to start though (because the AEC is full), so B2 should be awaiting in the scheduler's queue.
*
* As soon as the test code manually confirms E1 (and thus evicts it out of the AEC),
* it is expected that E2 begins and the scheduler's queue becomes empty again.
*/
TEST (election_scheduler, no_vacancy)
{
nano::test::system system{};

nano::node_config config = system.default_config ();
config.active_elections.size = 1;
config.frontiers_confirmation = nano::frontiers_confirmation_mode::disabled;

auto & node = *system.add_node (config);
nano::state_block_builder builder{};
nano::keypair key{};

// Activating accounts depends on confirmed dependencies. First, prepare 2 accounts
auto send = builder.make_block ()
.account (nano::dev::genesis_key.pub)
.previous (nano::dev::genesis->hash ())
.representative (nano::dev::genesis_key.pub)
.link (key.pub)
.balance (nano::dev::constants.genesis_amount - nano::Gxrb_ratio)
.sign (nano::dev::genesis_key.prv, nano::dev::genesis_key.pub)
.work (*system.work.generate (nano::dev::genesis->hash ()))
.build ();
ASSERT_EQ (nano::block_status::progress, node.process (send));
node.process_confirmed (nano::election_status{ send });

auto receive = builder.make_block ()
.account (key.pub)
.previous (0)
.representative (key.pub)
.link (send->hash ())
.balance (nano::Gxrb_ratio)
.sign (key.prv, key.pub)
.work (*system.work.generate (key.pub))
.build ();
ASSERT_EQ (nano::block_status::progress, node.process (receive));
node.process_confirmed (nano::election_status{ receive });

ASSERT_TIMELY (5s, nano::test::confirmed (node, { send, receive }));

// Second, process two eligible transactions
auto block1 = builder.make_block ()
.account (nano::dev::genesis_key.pub)
.previous (send->hash ())
.representative (nano::dev::genesis_key.pub)
.link (nano::dev::genesis_key.pub)
.balance (nano::dev::constants.genesis_amount - 2 * nano::Gxrb_ratio)
.sign (nano::dev::genesis_key.prv, nano::dev::genesis_key.pub)
.work (*system.work.generate (send->hash ()))
.build ();
ASSERT_EQ (nano::block_status::progress, node.process (block1));

// There is vacancy so it should be inserted
node.scheduler.priority.activate (node.ledger.tx_begin_read (), nano::dev::genesis_key.pub);
std::shared_ptr<nano::election> election{};
ASSERT_TIMELY (5s, (election = node.active.election (block1->qualified_root ())) != nullptr);

auto block2 = builder.make_block ()
.account (key.pub)
.previous (receive->hash ())
.representative (key.pub)
.link (key.pub)
.balance (0)
.sign (key.prv, key.pub)
.work (*system.work.generate (receive->hash ()))
.build ();
ASSERT_EQ (nano::block_status::progress, node.process (block2));

// There is no vacancy so it should stay queued
node.scheduler.priority.activate (node.ledger.tx_begin_read (), key.pub);
ASSERT_TIMELY_EQ (5s, node.scheduler.priority.size (), 1);
ASSERT_EQ (node.active.election (block2->qualified_root ()), nullptr);

// Election confirmed, next in queue should begin
election->force_confirm ();
ASSERT_TIMELY (5s, node.active.election (block2->qualified_root ()) != nullptr);
ASSERT_TRUE (node.scheduler.priority.empty ());
}
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