4b7aec2951 Add mempool tracepoints (virtu)
Pull request description:
This PR adds multiple mempool tracepoints.
| tracepoint | description |
| ------------- | ------------- |
| `mempool:added` | Is called when a transaction enters the mempool |
| `mempool:removed` | ... when a transaction is removed from the mempool |
| `mempool:replaced` | ... when a transaction is replaced in the mempool |
| `mempool:rejected` | ... when a transaction is rejected from entering the mempool |
The tracepoints are further documented in `docs/tracing.md`. Usage is demonstrated in the example script `contrib/tracing/mempool_monitor.py`. Interface tests are provided in `test/functional/interface_usdt_mempool.py`.
The rationale for passing the removal reason as a string instead of numerically is that the benefits of not having to maintain a redundant enum-string mapping seem to outweigh the small cost of string generation. The reject reason is passed as string as well, although in this instance the string does not have to be generated but is readily available.
ACKs for top commit:
0xB10C:
ACK 4b7aec2951
achow101:
ACK 4b7aec2951
Tree-SHA512: 6deb3ba2d1a061292fb9b0f885f7a5c4d11b109b838102d8a8f4828cd68f5cd03fa3fc64adc6fdf54a08a1eaccce261b0aa90c2b8c33cd5fd3828c8f74978958
Tracepoints for added, removed, replaced, and rejected transactions.
The removal reason is passed as string instead of a numeric value, since
the benefits of not having to maintain a redundant enum-string mapping
seem to outweigh the small cost of string generation. The reject reason
is passed as string as well, although here the string does not have to
be generated but is readily available.
So far, tracepoint PRs typically included two demo scripts: a naive
bpftrace script to show raw tracepoint data and a bcc script for a more
refined view. However, as some of the ongoing changes to bpftrace
introduce a certain degree of unreliability (running some of the
existing bpftrace scripts was not possible with standard kernels and
bpftrace packages on latest stable Ubuntu, Debian, and NixOS), this PR
includes only a single bcc script that fuses the functionality of former
bpftrace and bcc scripts.
fa818e103c txmempool: Remove unused clear() member function (MarcoFalke)
Pull request description:
Seems odd to have code in Bitcoin Core that is unused.
Moreover the function was broken (see https://github.com/bitcoin/bitcoin/pull/24145) and is brittle, as there is nothing that prevents similar bugs from re-appearing.
Fix both issues by replacing it with C++11 member initializers.
ACKs for top commit:
glozow:
ACK fa818e103c
Tree-SHA512: e79e44cac7d5a84d9ecc8e3f3b0b9a50e1e3ebec358b20ba5dac175ef07d1fbe338a20f83ee80f746f7c726c79e77f8be49e14bca57a41063da8a5302123c3a9
47c4b1f52a mempool: log/halt when CalculateMemPoolAncestors fails unexpectedly (stickies-v)
5481f65849 mempool: add AssumeCalculateMemPoolAncestors helper function (stickies-v)
f911bdfff9 mempool: use util::Result for CalculateMemPoolAncestors (stickies-v)
66e028f739 mempool: use util::Result for CalculateAncestorsAndCheckLimits (stickies-v)
Pull request description:
Upon reviewing the documentation for `CTxMemPool::CalculateMemPoolAncestors`, I noticed `setAncestors` was meant to be an `out` parameter but actually is an `in,out` parameter, as can be observed by adding `assert(setAncestors.empty());` as the first line in the function and running `make check`. This PR fixes this unexpected behaviour and introduces refactoring improvements to make intents and effects of the code more clear.
## Unexpected behaviour
This behaviour occurs only in the package acceptance path, currently only triggered by `testmempoolaccept` and `submitpackage` RPCs.
In `MemPoolAccept::AcceptMultipleTransactions()`, we first call `PreChecks()` and then `SubmitPackage()` with the same `Workspace ws` reference. `PreChecks` leaves `ws.m_ancestors` in a potentially non-empty state, before it is passed on to `MemPoolAccept::SubmitPackage`. `SubmitPackage` is the only place where `setAncestors` isn't guaranteed to be empty before calling `CalculateMemPoolAncestors`. The most straightforward fix is to just forcefully clear `setAncestors` at the beginning of CalculateMemPoolAncestors, which is done in the first bugfix commit.
## Improvements
### Return value instead of out-parameters
This PR updates the function signatures for `CTxMemPool::CalculateMemPoolAncestors` and `CTxMemPool::CalculateAncestorsAndCheckLimits` to use a `util::Result` return type and eliminate both the `setAncestors` `in,out`-parameter as well as the error string. It simplifies the code and makes the intent and effects more explicit.
### Observability
There are 7 instances where we currently call `CalculateMemPoolAncestors` without actually checking if the function succeeded because we assume that it can't fail, such as in [miner.cpp](69b10212ea/src/node/miner.cpp (L399)). This PR adds a new wrapper `AssumeCalculateMemPoolAncestors` function that logs such unexpected failures, or in case of debug builds even halts the program. It's not crucial to the objective, more of an observability improvement that seems sensible to add on here.
ACKs for top commit:
achow101:
ACK 47c4b1f52a
w0xlt:
ACK https://github.com/bitcoin/bitcoin/pull/26289/commits/47c4b1f52ab8d95d7deef83050bad49d1e3e5990
glozow:
ACK 47c4b1f52a
furszy:
light code review ACK 47c4b1f5
aureleoules:
ACK 47c4b1f52a
Tree-SHA512: d908dad00d1a5645eb865c4877cc0bae74b9cd3332a3641eb4a285431aef119f9fc78172d38b55c592168a73dae83242e6af3348815f7b37cbe2d448a3a58648
When CalculateMemPoolAncestors fails unexpectedly (e.g. it exceeds
ancestor/descendant limits even though we expect no limits to be applied),
add an error log entry for increased visibility. For debug builds,
the application will even halt completely since this is not supposed
to happen.
There are quite a few places that assume CalculateMemPoolAncestors
will return a value without raising an error. This helper function
adds logging (and Assume for debug builds) that ensures robustness
but increases visibility in case of unexpected failures
c8dc0e3eaa refactor: Inline `CTxMemPoolEntry` class's functions (Hennadii Stepanov)
75bbe594e5 refactor: Move `CTxMemPoolEntry` class to its own module (Hennadii Stepanov)
Pull request description:
This PR:
- gets rid of the `policy/fees` -> `txmempool` -> `policy/fees` circular dependency
- is an alternative to #13949, which nukes only one circular dependency
ACKs for top commit:
ryanofsky:
Code review ACK c8dc0e3eaa. Just include and whitespace changes since last review, and there's a moveonly commit now so it's very easy to review
theStack:
Code-review ACK c8dc0e3eaa
glozow:
utACK c8dc0e3eaa, agree these changes are an improvement.
Tree-SHA512: 36ece824e6ed3ab1a1e198b30a906c8ac12de24545f840eb046958a17315ac9260c7de26e11e2fbab7208adc3d74918db7a7e389444130f8810548ca2e81af41
