This commit implements most of BIP0143 by adding logic to implement the
new sighash calculation, signing, and additionally introduces the
HashCache optimization which eliminates the O(N^2) computational
complexity for the SIGHASH_ALL sighash type.
The HashCache struct is the equivalent to the existing SigCache struct,
but for caching the reusable midstate for transactions which are
spending segwitty outputs.
This commit implements the new witness encoding/decoding for
transactions as specified by BIP0144. After segwit activation, a
special transaction encoding is used to signal to upgraded nodes that
the transaction being deserialized bares witness data. The prior
BtcEncode and BtcDecode methods have been extended to be aware of the
new signaling bytes and the encoding of witness data within
transactions.
Additionally, a new method has been added to calculate the “stripped
size” of a transaction/block which is defined as the size of a
transaction/block *excluding* any witness data.
This commit adds the new inventory types for segwit which are used by
the responder to explicitly request that transactions/blocks sent for a
particular inv hash should include all witness data.
This commit modifies the existing wire.Message interface to introduce a
new MessageEncoding variant which dictates the exact encoding to be
used when serializing and deserializing messages. Such an option is now
necessary due to the segwit soft-fork package, as btcd will need to be
able to optionally encode transactions/blocks without witness data to
un-upgraded peers.
Two new functions have been introduced: ReadMessageWithEncodingN and
WriteMessageWithEncodingN which wrap BtcDecode/BtcEncode with the
desired encoding format.
This commit introduces the new SFNodeWitness service bit which has been
added to the protocol as part of BIP0144. The new service bit allows
peers on the network to signal their acceptance and adherence to the
new rules defined as part of the segwit soft-fork package.
The github markdown interpreter has been changed such that it no longer
allows spaces in between the brackets and parenthesis of links and now
requires a newline in between anchors and other formatting. This
updates all of the markdown files accordingly.
While here, it also corrects a couple of inconsistencies in some of the
README.md files.
This simplifies the code based on the recommendations of the gosimple
lint tool.
Also, it increases the deadline for the linters to run to 10 minutes and
reduces the number of threads that is uses. This is being done because
the Travis environment has become increasingly slower and it also seems
to be hampered by too many threads running concurrently.
Replace assignments to individual fields of wire.NetAddress with
creating the entire object at once, as one would do if the type was
immutable.
In some places this replaces the creation of a NetAddress with a
high-precision timestamp with a call to a 'constructor' that converts
the timestamp to single second precision. For consistency, the tests
have also been changed to use single-precision timestamps.
Lastly, the number of allocations in readNetAddress have been reduced by
reading the services directly into the NetAddress instead of first into
a temporary variable.
This commit adds all of the infrastructure needed to support BIP0009
soft forks.
The following is an overview of the changes:
- Add new configuration options to the chaincfg package which allows the
rule deployments to be defined per chain
- Implement code to calculate the threshold state as required by BIP0009
- Use threshold state caches that are stored to the database in order
to accelerate startup time
- Remove caches that are invalid due to definition changes in the
params including additions, deletions, and changes to existing
entries
- Detect and warn when a new unknown rule is about to activate or has
been activated in the block connection code
- Detect and warn when 50% of the last 100 blocks have unexpected
versions.
- Remove the latest block version from wire since it no longer applies
- Add a version parameter to the wire.NewBlockHeader function since the
default is no longer available
- Update the miner block template generation code to use the calculated
block version based on the currently defined rule deployments and
their threshold states as of the previous block
- Add tests for new error type
- Add tests for threshold state cache
Rather than accepting a net.Addr interface and returning an error when
it's not specifically a *net.TCPConn, just accept a *net.TCPConn
directly so the compiler will assert it. Also, remove the error return
since it can no longer occur.
This function is a legacy function from way back during initial
development. Nothing actually uses it and it's not very useful anyways
since it requires the connection to be a specific type (net.TCPConn) and
therefore doesn't work right with things that typically provide their
own net.Conn implementation like proxies.
This modifies the NewMsgTx function to accept the transaction version as
a parameter and updates all callers.
The reason for this change is so the transaction version can be bumped
in wire without breaking existing tests and to provide the caller with
the flexibility to create the specific transaction version they desire.
This commit introduces the concept of “sequence locks” borrowed from
Bitcoin Core for converting an input’s relative time-locks to an
absolute value based on a particular block for input maturity
evaluation.
A sequence lock is computed as the most distant maturity height/time
amongst all the referenced outputs within a particular transaction.
A transaction with sequence locks activated within any of its inputs
can *only* be included within a block if from the point-of-view of that
block either the time-based or height-based maturity for all referenced
inputs has been met.
A transaction with sequence locks can only be accepted to the mempool
iff from the point-of-view of the *next* (yet to be found block) all
referenced inputs within the transaction are mature.
The protocol was silently upgrade in Core some time ago to enforce a
limit of 256 for the user agent in version messages. This updates wire
to coincide with that change and consequently includes a wire version
bump to 0.4.1.
This is mostly a backport of some of the same modifications made in
Decred along with a few additional things cleaned up. In particular,
this updates the code to make use of the new chainhash package.
Also, since this required API changes anyways and the hash algorithm is
no longer tied specifically to SHA, all other functions throughout the
code base which had "Sha" in their name have been changed to Hash so
they are not incorrectly implying the hash algorithm.
The following is an overview of the changes:
- Remove the wire.ShaHash type
- Update all references to wire.ShaHash to the new chainhash.Hash type
- Rename the following functions and update all references:
- wire.BlockHeader.BlockSha -> BlockHash
- wire.MsgBlock.BlockSha -> BlockHash
- wire.MsgBlock.TxShas -> TxHashes
- wire.MsgTx.TxSha -> TxHash
- blockchain.ShaHashToBig -> HashToBig
- peer.ShaFunc -> peer.HashFunc
- Rename all variables that included sha in their name to include hash
instead
- Update for function name changes in other dependent packages such as
btcutil
- Update copyright dates on all modified files
- Update glide.lock file to use the required version of btcutil
Putting the test code in the same package makes it easier for forks
since they don't have to change the import paths as much and it also
gets rid of the need for internal_test.go to bridge.
This same thing should probably be done for the majority of the code
base.
This commit drastically reduces the number of allocations needed to
deserialize a transaction and its scripts by using the combination of a
free list for initially deserializing the individual scripts along with
copying them into a single contiguous byte slice after the final size is
known and modifying each script in the transaction to point to its
location within the contiguous blob.
The end result is only a single allocation that holds all of the scripts
for a transaction regardless of the total number of scripts it has.
The script free list allows a maximum of 12,500 items with each buffer
being 512 bytes. This implies it will have a peak usage of 6.1MB. The
values were chosen based on profiling data and a desire to allow at
least 100 scripts per transaction to be simultaneously deserialized by
125 peers.
Also, while optimizing, decode directly into the existing previous
outpoint structure of each transaction input in order to avoid the extra
allocation per input that is otherwise caused when the local escapes to
the heap.
The following is a before and after comparison of the allocations
with the benchmarks that did not change removed:
benchmark old allocs new allocs delta
-----------------------------------------------------------
ReadTxOut 1 0 -100.00%
ReadTxIn 2 0 -100.00%
DeserializeTxSmall 7 5 -28.57%
DeserializeTxLarge 11146 6 -99.95%
The current code involves a ton of small allocations which is harsh on
the garbage collector and in turn causes a lot of addition runtime
overhead both in terms of additional memory and processing time.
In order to improve the situation, this drasticially reduces the number
of allocations by creating contiguous slices of objects and
deserializing into them. Since the final data structures consist of
slices of pointers to the objects, they are constructed by pointing them
into the appropriate offset of the contiguous slice.
This could be improved upon even further by converting all of the data
structures provided the wire package to be slices of contiguous objects
directly, however that would be a major breaking API change and would
end up requiring updating a lot more code in every caller. I do think
that ultimately the API should be changed, but the changes in this
commit already makes a massive difference and it doesn't require
touching any of the callers, so it is a good place to begin.
The following is a before and after comparison of the allocations
with the benchmarks that did not change removed:
benchmark old allocs new allocs delta
-----------------------------------------------------------
DeserializeTxLarge 16715 11146 -33.32%
DecodeGetHeaders 501 2 -99.60%
DecodeHeaders 2001 2 -99.90%
DecodeGetBlocks 501 2 -99.60%
DecodeAddr 3001 2002 -33.29%
DecodeInv 50003 3 -99.99%
DecodeNotFound 50002 3 -99.99%
DecodeMerkleBlock 107 3 -97.20%
Since the protocol encodes timestamps differently depending on the
message, the code currently decodes into a local variable and then
converts it to a time.Time. However, this causes an allocation due to
the local having to escape to the heap in order for the readElement
function to write to it.
So, in order to avoid that, this introduces two new types for a
timestamp named uint32Time and int64Time that are encoded as the
respective type on the read. When calling the readElements function,
the time.Time field in the message is cast to a pointer of the
appropriate type which effectively allows the allocations to be avoided.
The following is a before and after comparison of the allocations
with the benchmarks that did not change removed:
benchmark old allocs new allocs delta
----------------------------------------------------------------------
ReadBlockHeader 1 0 -100.00%
DecodeHeaders 4001 2001 -49.99%
DecodeAddr 4001 3001 -24.99%
DecodeMerkleBlock 108 107 -0.93%
This introduces a new binary free list which provides a concurrent safe
list of unused buffers for the purpose of serializing and deserializing
primitive integers to their raw binary bytes.
For convenience, the type also provides functions for each of the
primitive unsigned integers that automatically obtain a buffer from the
free list, perform the necessary binary conversion, read from or write
to the given io.Reader or io.Writer, and return the buffer to the free
list.
A global instance of the type has been introduced with a maximum number
of 1024 items. Since each buffer is 8 bytes, it will consume a maximum
of 8KB. Theoretically, this value would only allow up to 1024 peers
simultaneously reading and writing without having to resort to burdening
the garbage collector with additional allocations. However, due to the
fact the code is designed in such a way that the buffers are quickly
used and returned to the free list, in practice it can support much more
than 1024 peers without involving the garbage collector since it is
highly unlikely every peer would need a buffer at the exact same time.
The following is a before and after comparison of the allocations
with the benchmarks that did not change removed:
benchmark old allocs new allocs delta
-------------------------------------------------------------
WriteVarInt1 1 0 -100.00%
WriteVarInt3 1 0 -100.00%
WriteVarInt5 1 0 -100.00%
WriteVarInt9 1 0 -100.00%
ReadVarInt1 1 0 -100.00%
ReadVarInt3 1 0 -100.00%
ReadVarInt5 1 0 -100.00%
ReadVarInt9 1 0 -100.00%
ReadVarStr4 3 2 -33.33%
ReadVarStr10 3 2 -33.33%
WriteVarStr4 2 1 -50.00%
WriteVarStr10 2 1 -50.00%
ReadOutPoint 1 0 -100.00%
WriteOutPoint 1 0 -100.00%
ReadTxOut 3 1 -66.67%
WriteTxOut 2 0 -100.00%
ReadTxIn 5 2 -60.00%
WriteTxIn 3 0 -100.00%
DeserializeTxSmall 15 7 -53.33%
DeserializeTxLarge 33428 16715 -50.00%
SerializeTx 8 0 -100.00%
ReadBlockHeader 7 1 -85.71%
WriteBlockHeader 10 4 -60.00%
DecodeGetHeaders 1004 501 -50.10%
DecodeHeaders 18002 4001 -77.77%
DecodeGetBlocks 1004 501 -50.10%
DecodeAddr 9002 4001 -55.55%
DecodeInv 150005 50003 -66.67%
DecodeNotFound 150004 50002 -66.67%
DecodeMerkleBlock 222 108 -51.35%
TxSha 10 2 -80.00%
This adds decode benchmarks for several of the messages that profiling
has identified to cause a lot of allocations in addition to those that
already exist. By adding these benchmarks, it makes it easier to get
allocation and speed statistics which can in turn be used to compare
future improvements.
The following bencharmarks have been added:
DecodeGetHeaders, DecodeHeaders, DecodeGetBlocks, DecodeAddr, DecodeInv,
DecodeNotFound, and DecodeMerkleBlock
For reference, here is the benchmark data as of this commit.
DecodeGetHeaders 93261 ns/op 24120 B/op 1004 allocs/op
DecodeHeaders 2071263 ns/op 368399 B/op 18002 allocs/op
DecodeGetBlocks 92486 ns/op 24120 B/op 1004 allocs/op
DecodeAddr 850608 ns/op 136202 B/op 9002 allocs/op
DecodeInv 17107172 ns/op 3601447 B/op 150004 allocs/op
DecodeNotFound 17522225 ns/op 3601444 B/op 150004 allocs/op
DecodeMerkleBlock 21062 ns/op 5192 B/op 222 allocs/op
This modifies the benchmarks in the wire package to avoid creating a new
reader for each iteration. This is useful since it means that showing
the memory allocations will only show the function under test instead of
the allocation for the benchmark setup as well.
The following is a before and after comparison of the allocations
with the benchmarks that did not change removed:
benchmark old allocs new allocs delta
------------------------------------------------------------
ReadVarInt1 2 1 -50.00%
ReadVarInt3 2 1 -50.00%
ReadVarInt5 2 1 -50.00%
ReadVarInt9 2 1 -50.00%
ReadVarStr4 4 3 -25.00%
ReadVarStr10 4 3 -25.00%
ReadOutPoint 2 1 -50.00%
ReadTxOut 4 3 -25.00%
ReadTxIn 6 5 -16.67%
DeserializeTxSmall 16 15 -6.25%
DeserializeTxLarge 33430 33428 -0.01%
ReadBlockHeader 8 7 -12.50%
This adds a benchmark for deserializing a large transaction that is
often referred to as the megatransaction since it is the largest Bitcoin
transaction mined to date. It consists of 5569 inputs and 1 output and
its hash is:
bb41a757f405890fb0f5856228e23b715702d714d59bf2b1feb70d8b2b4e3e08.
This is being done so there is a benchmark that tests more of a
worst-case scenario which is a better candidate for identifying and
testing improvements.
The following benchmark results shows the how much more intensive this
transaction is over the existing mock transaction:
DeserializeTxSmall 1000000 1751 ns/op 376 B/op 16 allocs/op
DeserializeTxLarge 300 5093980 ns/op 1672829 B/op 33430 allocs/op
This commit is the first stage of several that are planned to convert
the blockchain package into a concurrent safe package that will
ultimately allow support for multi-peer download and concurrent chain
processing. The goal is to update btcd proper after each step so it can
take advantage of the enhancements as they are developed.
In addition to the aforementioned benefit, this staged approach has been
chosen since it is absolutely critical to maintain consensus.
Separating the changes into several stages makes it easier for reviewers
to logically follow what is happening and therefore helps prevent
consensus bugs. Naturally there are significant automated tests to help
prevent consensus issues as well.
The main focus of this stage is to convert the blockchain package to use
the new database interface and implement the chain-related functionality
which it no longer handles. It also aims to improve efficiency in
various areas by making use of the new database and chain capabilities.
The following is an overview of the chain changes:
- Update to use the new database interface
- Add chain-related functionality that the old database used to handle
- Main chain structure and state
- Transaction spend tracking
- Implement a new pruned unspent transaction output (utxo) set
- Provides efficient direct access to the unspent transaction outputs
- Uses a domain specific compression algorithm that understands the
standard transaction scripts in order to significantly compress them
- Removes reliance on the transaction index and paves the way toward
eventually enabling block pruning
- Modify the New function to accept a Config struct instead of
inidividual parameters
- Replace the old TxStore type with a new UtxoViewpoint type that makes
use of the new pruned utxo set
- Convert code to treat the new UtxoViewpoint as a rolling view that is
used between connects and disconnects to improve efficiency
- Make best chain state always set when the chain instance is created
- Remove now unnecessary logic for dealing with unset best state
- Make all exported functions concurrent safe
- Currently using a single chain state lock as it provides a straight
forward and easy to review path forward however this can be improved
with more fine grained locking
- Optimize various cases where full blocks were being loaded when only
the header is needed to help reduce the I/O load
- Add the ability for callers to get a snapshot of the current best
chain stats in a concurrent safe fashion
- Does not block callers while new blocks are being processed
- Make error messages that reference transaction outputs consistently
use <transaction hash>:<output index>
- Introduce a new AssertError type an convert internal consistency
checks to use it
- Update tests and examples to reflect the changes
- Add a full suite of tests to ensure correct functionality of the new
code
The following is an overview of the btcd changes:
- Update to use the new database and chain interfaces
- Temporarily remove all code related to the transaction index
- Temporarily remove all code related to the address index
- Convert all code that uses transaction stores to use the new utxo
view
- Rework several calls that required the block manager for safe
concurrency to use the chain package directly now that it is
concurrent safe
- Change all calls to obtain the best hash to use the new best state
snapshot capability from the chain package
- Remove workaround for limits on fetching height ranges since the new
database interface no longer imposes them
- Correct the gettxout RPC handler to return the best chain hash as
opposed the hash the txout was found in
- Optimize various RPC handlers:
- Change several of the RPC handlers to use the new chain snapshot
capability to avoid needlessly loading data
- Update several handlers to use new functionality to avoid accessing
the block manager so they are able to return the data without
blocking when the server is busy processing blocks
- Update non-verbose getblock to avoid deserialization and
serialization overhead
- Update getblockheader to request the block height directly from
chain and only load the header
- Update getdifficulty to use the new cached data from chain
- Update getmininginfo to use the new cached data from chain
- Update non-verbose getrawtransaction to avoid deserialization and
serialization overhead
- Update gettxout to use the new utxo store versus loading
full transactions using the transaction index
The following is an overview of the utility changes:
- Update addblock to use the new database and chain interfaces
- Update findcheckpoint to use the new database and chain interfaces
- Remove the dropafter utility which is no longer supported
NOTE: The transaction index and address index will be reimplemented in
another commit.
This implements the wire protocol encoding portion of a new
sendheaders message as described by BIP0130. It purpose is to request
that a peer sends header commands instead of inv commands when
announcing new blocks. This includes a protocol version bump to 70012
and a wire version bump to 0.4.0.
Note that this does not implement logic to handle the command in btcd,
rather it only makes the command available at the wire protocol level.
A future commit which honors the command and therefore provides full
BIP0130 support is still required.
