Include an adjustment to mempool_tests.cpp due to the additional memory used by
txgraph.
Includes a temporary change to the mempool_ephemeral_dust.py functional test,
due to validation checks being reordered. This change will revert once the RBF
rules are changed in a later commit.
Simplifies `m_tx_inventory_to_send` a bit by making it a set of Wtxids.
Wtxid relay is prevalent throughout the network, so the complexity of
dealing with a GenTxid in this data structure isn't necessary.
For peers that aren't wtxid relay, the txid is now retrieved from our
mempool entry when the inv is constructed.
During Initial Block Download, the mempool is usually empty, but `CTxMemPool::removeForBlock` is still called for every connected block where we:
* iterate over every transaction in the block even though none will be found in the empty `mapTx`, always leaving `txs_removed_for_block` empty...
* which is pre-allocated regardless with 40 bytes * vtx.size(), even though it will always remain empty.
This change introduces a minor performance optimization by only executing the loop if any of the core mempool maps have any contents.
The call to `MempoolTransactionsRemovedForBlock` and the updates to the rolling fee logic remain unchanged.
The `removeForBlock` was also updated stylistically to match the surrounding methods and a clarification was added to clarify that it affects fee estimation as well.
a60f863d3e scripted-diff: Replace GenTxidVariant with GenTxid (marcofleon)
c8ba199598 Remove old GenTxid class (marcofleon)
072a198ea4 Convert remaining instances of GenTxid to GenTxidVariant (marcofleon)
1b528391c7 Convert `txrequest` to GenTxidVariant (marcofleon)
bde4579b07 Convert `txdownloadman_impl` to GenTxidVariant (marcofleon)
c876a892ec Replace GenTxid with Txid/Wtxid overloads in `txmempool` (marcofleon)
de858ce2be move-only: make GetInfo a private CTxMemPool member (stickies-v)
eee473d9f3 Convert `CompareInvMempoolOrder` to GenTxidVariant (marcofleon)
243553d590 refactor: replace get_iter_from_wtxid with GetIter(const Wtxid&) (stickies-v)
fcf92fd640 refactor: make CTxMemPool::GetIter strongly typed (marcofleon)
11d28f21bb Implement GenTxid as a variant (marcofleon)
Pull request description:
Part of the [type safety refactor](https://github.com/bitcoin/bitcoin/pull/32189).
This PR changes the GenTxid class to a variant, which holds both Txids and Wtxids. This provides compile-time type safety and eliminates the manual type check (bool m_is_wtxid). Variables that can be either a Txid or a Wtxid are now using the new GenTxid variant, instead of uint256.
ACKs for top commit:
w0xlt:
ACK a60f863d3e
dergoegge:
Code review ACK a60f863d3e
maflcko:
review ACK a60f863d3e🎽
theStack:
Code-review ACK a60f863d3e
Tree-SHA512: da9b73b7bdffee2eb9281a409205519ac330d3336094d17681896703fbca8099608782c9c85801e388e4d90af5af8abf1f34931f57bbbe6e9674d802d6066047
Now that we are storing `CTxMemPool::CompareDepthAndScore` parameters using
`std::variant` we have no portable zero-overhead way of accessing them,
so use `std::visit` and drop `bool wtxid` in-parameter.
Co-authored-by: stickies-v <stickies-v@protonmail.com>
This allows adding a GetIter(const Wtxid&) overload in a next
commit, making it easier to visit this function from a variant.
Co-authored-by: stickies-v <stickies-v@protonmail.com>
Also explicitly check for txid equality rather than transaction equality as the
former is a tighter constraint if witness data is included when comparing the
full transactions.
Co-authored-by: glozow <gloriajzhao@gmail.com>
Rather than individually calling addUnchecked for each transaction added in a
changeset (after removing all the to-be-removed transactions), instead we can
take advantage of boost::multi_index's splicing features to extract and insert
entries directly from the staging multi_index into mapTx.
This has the immediate advantage of saving allocation overhead for mempool
entries which have already been allocated once. This also means that the memory
locations of mempool entries will not change when transactions go from staging
to the main mempool.
Additionally, eliminate addUnchecked and require all new transactions to enter
the mempool via a CTxMemPoolChangeSet.
Before this commit, we would always prepare tracepoint arguments
regardless of the tracepoint being used or not. While we already made
sure not to include expensive arguments in our tracepoints, this
commit introduces gating to make sure the arguments are only prepared
if the tracepoints are actually used. This is a win-win improvement
to our tracing framework. For users not interested in tracing, the
overhead is reduced to a cheap 'greater than 0' compare. As the
semaphore-gating technique used here is available in bpftrace, bcc,
and libbpf, users interested in tracing don't have to change their
tracing scripts while profiting from potential future tracepoints
passing slightly more expensive arguments. An example are mempool
tracepoints that pass serialized transactions. We've avoided the
serialization in the past as it was too expensive.
Under the hood, the semaphore-gating works by placing a 2-byte
semaphore in the '.probes' ELF section. The address of the semaphore
is contained in the ELF note providing the tracepoint information
(`readelf -n ./src/bitcoind | grep NT_STAPSDT`). Tracing toolkits
like bpftrace, bcc, and libbpf increase the semaphore at the address
upon attaching to the tracepoint. We only prepare the arguments and
reach the tracepoint if the semaphore is greater than zero. The
semaphore is decreased when detaching from the tracepoint.
This also extends the "Adding a new tracepoint" documentation to
include information about the semaphores and updated step-by-step
instructions on how to add a new tracepoint.
This new function takes the populated sets of
direct and all conflicts computed in the current
mempool, assuming the replacements are a single
chunk, and computes a diagram check.
The diagram check only works against cluster
sizes of 2 or less, and fails if it encounters
a different topology.
Co-authored-by: Suhas Daftuar <sdaftuar@chaincode.com>
This is done in preparation for the next two commits, where the
CMainSignals are de-globalized.
This avoids adding new constructor arguments to the ChainstateManager
and CTxMemPool classes over the next two commits.
This could also allow future tests that are only interested in the
internal behaviour of the classes to forgo instantiating the signals.
29029df5c7 [doc] v3 signaling in mempool-replacements.md (glozow)
e643ea795e [fuzz] v3 transactions and sigop-adjusted vsize (glozow)
1fd16b5c62 [functional test] v3 transaction submission (glozow)
27c8786ba9 test framework: Add and use option for tx-version in MiniWallet methods (MarcoFalke)
9a1fea55b2 [policy/validation] allow v3 transactions with certain restrictions (glozow)
eb8d5a2e7d [policy] add v3 policy rules (glozow)
9a29d470fb [rpc] return full string for package_msg and package-error (glozow)
158623b8e0 [refactor] change Workspace::m_conflicts and adjacent funcs/structs to use Txid (glozow)
Pull request description:
See #27463 for overall package relay tracking.
Delving Bitcoin discussion thread: https://delvingbitcoin.org/t/v3-transaction-policy-for-anti-pinning/340
Delving Bitcoin discussion for LN usage: https://delvingbitcoin.org/t/lightning-transactions-with-v3-and-ephemeral-anchors/418
Rationale:
- There are various pinning problems with RBF and our general ancestor/descendant limits. These policies help mitigate many pinning attacks and make package RBF feasible (see #28984 which implements package RBF on top of this). I would focus the most here on Rule 3 pinning. [1][2]
- Switching to a cluster-based mempool (see #27677 and #28676) requires the removal of CPFP carve out, which applications depend on. V3 + package RBF + ephemeral anchors + 1-parent-1-child package relay provides an intermediate solution.
V3 policy is for "Priority Transactions." [3][4] It allows users to opt in to more restrictive topological limits for shared transactions, in exchange for the more robust fee-bumping abilities that offers. Even though we don't have cluster limits, we are able to treat these transactions as having as having a maximum cluster size of 2.
Immediate benefits:
- You can presign a transaction with 0 fees (not just 1sat/vB!) and add a fee-bump later.
- Rule 3 pinning is reduced by a significant amount, since the attacker can only attach a maximum of 1000vB to your shared transaction.
This also enables some other cool things (again see #27463 for overall roadmap):
- Ephemeral Anchors
- Package RBF for these 1-parent-1-child packages. That means e.g. a commitment tx + child can replace another commitment tx using the child's fees.
- We can transition to a "single anchor" universe without worrying about package limit pinning. So current users of CPFP carve out would have something else to use.
- We can switch to a cluster-based mempool [5] (#27677#28676), which removes CPFP carve out [6].
[1]: Original mailing list post and discussion about RBF pinning problems https://gist.github.com/glozow/25d9662c52453bd08b4b4b1d3783b9ff, https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-January/019817.html
[2]: A FAQ is "we need this for cluster mempool, but is this still necessary afterwards?" There are some pinning issues that are fixed here and not fully fixed in cluster mempool, so we will still want this or something similar afterward.
[3]: Mailing list post for v3 https://lists.linuxfoundation.org/pipermail/bitcoin-dev/2022-September/020937.html
[4]: Original PR #25038 also contains a lot of the discussion
[5]: https://delvingbitcoin.org/t/an-overview-of-the-cluster-mempool-proposal/393/7
[6]: https://delvingbitcoin.org/t/an-overview-of-the-cluster-mempool-proposal/393#the-cpfp-carveout-rule-can-no-longer-be-supported-12
ACKs for top commit:
sdaftuar:
ACK 29029df5c7
achow101:
ACK 29029df5c7
instagibbs:
ACK 29029df5c7 modulo that
Tree-SHA512: 9664b078890cfdca2a146439f8835c9d9ab483f43b30af8c7cd6962f09aa557fb1ce7689d5e130a2ec142235dbc8f21213881baa75241c5881660f9008d68450
It's preferable to use type-safe transaction identifiers to avoid
confusing txid and wtxid. The next commit will add a reference to this
set; we use this opportunity to change it to Txid ahead of time instead
of adding new uses of uint256.
Update CheckPackageLimits to use util::Result to pass the error message
instead of out parameter.
Also update test to reflect the error message from `CTxMempool`
`CheckPackageLimits` output.
91504cbe0d rpc: `SyncWithValidationInterfaceQueue` on fee estimation RPC's (ismaelsadeeq)
714523918b tx fees, policy: CBlockPolicyEstimator update from `CValidationInterface` notifications (ismaelsadeeq)
dff5ad3b99 CValidationInterface: modify the parameter of `TransactionAddedToMempool` (ismaelsadeeq)
91532bd382 tx fees, policy: update `CBlockPolicyEstimator::processBlock` parameter (ismaelsadeeq)
bfcd401368 CValidationInterface, mempool: add new callback to `CValidationInterface` (ismaelsadeeq)
0889e07987 tx fees, policy: cast with static_cast instead of C-Style cast (ismaelsadeeq)
a0e3eb7549 tx fees, policy: bugfix: move `removeTx` into reason != `BLOCK` condition (ismaelsadeeq)
Pull request description:
This is an attempt to #11775
This Pr will enable fee estimator to listen to ValidationInterface notifications to process new transactions added and removed from the mempool.
This PR includes the following changes:
- Added a new callback to the Validation Interface `MempoolTransactionsRemovedForConnectedBlock`, which notifies listeners about the transactions that have been removed due to a new block being connected, along with the height at which the transactions were removed.
- Modified the `TransactionAddedToMempool` callback parameter to include additional information about the transaction needed for fee estimation.
- Updated `CBlockPolicyEstimator` to process transactions using` CTransactionRef` instead of `CTxMempoolEntry.`
- Implemented the `CValidationInterface` interface in `CBlockPolicyEstimater` and overridden the `TransactionAddedToMempool`, `TransactionRemovedFromMempool`, and `MempoolTransactionsRemovedForConnectedBlock` methods to receive updates from their notifications.
Prior to this PR, the fee estimator updates from the mempool, i.e whenever a new block is connected all transactions in the block that are in our mempool are going to be removed using the `removeForBlock` function in `txmempool.cpp`.
This removal triggered updates to the fee estimator. As a result, the fee estimator would block mempool's `cs` until it finished updating every time a new block was connected.
Instead of being blocked only on mempool tx removal, we were blocking on both tx removal and fee estimator updating.
If we want to further improve fee estimation, or add heavy-calulation steps to it, it is currently not viable as we would be slowing down block relay in the process
This PR is smaller in terms of the changes made compared to #11775, as it focuses solely on enabling fee estimator updates from the validationInterface/cscheduler thread notifications.
I have not split the validation interface because, as I understand it, the rationale behind the split in #11775 was to have `MempoolInterface` signals come from the mempool and `CValidationInterface` events come from validation. I believe this separation can be achieved in a separate refactoring PR when the need arises.
Also left out some commits from #11775
- Some refactoring which are no longer needed.
- Handle reorgs much better in fee estimator.
- Track witness hash malleation in fee estimator
I believe they are a separate change that can come in a follow-up after this.
ACKs for top commit:
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ACK 91504cbe0d
TheCharlatan:
Re-ACK 91504cbe0d
willcl-ark:
ACK 91504cbe0d
Tree-SHA512: 846dfb9da57a8a42458827b8975722d153907fe6302ad65748d74f311e1925557ad951c3d95fe71fb90ddcc8a3710c45abb343ab86b88780871cb9c38c72c7b1
705e3f1de0 refactor: Make CTxMemPoolEntry only explicitly copyable (TheCharlatan)
Pull request description:
This has the goal of prohibiting users from accidentally creating runtime failures, e.g. by interacting with iterator_to with a copied entry. This was brought up here: https://github.com/bitcoin/bitcoin/pull/28886#issuecomment-1814794954.
CTxMemPoolEntry is already implicitly not move-constructable. So be explicit about this and use a std::list to collect the values in the policy_estimator fuzz test instead of a std::vector.
ACKs for top commit:
maflcko:
ACK 705e3f1de0🌯
achow101:
ACK 705e3f1de0
ajtowns:
ACK 705e3f1de0
ismaelsadeeq:
ACK 705e3f1de0
Tree-SHA512: 62056905c679c919d00f9ae065ed66ac986e7e7062015aea542843d8deecda57104d7a68d002f7b20afa3164f8e9215d2d2d002c167224129540e3b1bd0712cc
`CBlockPolicyEstimator` will implement `CValidationInterface` and
subscribe to its notification to process transactions added and removed
from the mempool.
Re-delegate calculation of `validForFeeEstimation` from validation to fee estimator.
Also clean up the validForFeeEstimation arg thats no longer needed in `CTxMempool`.
Co-authored-by: Matt Corallo <git@bluematt.me>
