MarcoFalke 5029e94f85
Merge #14519: tests: add utility to easily profile node performance with perf
13782b8ba8 docs: add perf section to developer docs (James O'Beirne)
58180b5fd4 tests: add utility to easily profile node performance with perf (James O'Beirne)

Pull request description:

  Adds a context manager to easily (and selectively) profile node performance during functional test execution using `perf`.

  While writing some tests, I encountered some odd bitcoind slowness. I wrote up a utility (`TestNode.profile_with_perf`) that generates performance diagnostics for a node by running `perf` during the execution of a particular region of test code.

  `perf` usage is detailed in the excellent (and sadly unmerged) https://github.com/bitcoin/bitcoin/pull/12649; all due props to @eklitzke.

  ### Example

  ```python
  with node.profile_with_perf("large-msgs"):
      for i in range(200):
          node.p2p.send_message(some_large_msg)
      node.p2p.sync_with_ping()
  ```

  This generates a perf data file in the test node's datadir (`/tmp/testtxmpod0y/node0/node-0-TestName-large-msgs.perf.data`).

  Running `perf report` generates nice output about where the node spent most of its time while running that part of the test:

  ```bash
  $ perf report -i /tmp/testtxmpod0y/node0/node-0-TestName-large-msgs.perf.data --stdio \
    | c++filt \
    | less

  # To display the perf.data header info, please use --header/--header-only options.
  #
  #
  # Total Lost Samples: 0
  #
  # Samples: 135  of event 'cycles:pp'
  # Event count (approx.): 1458205679493582
  #
  # Children      Self  Command          Shared Object        Symbol
  # ........  ........  ...............  ...................  ........................................................................................................................................................................................................................................................................
  #
      70.14%     0.00%  bitcoin-net      bitcoind             [.] CNode::ReceiveMsgBytes(char const*, unsigned int, bool&)
                  |
                  ---CNode::ReceiveMsgBytes(char const*, unsigned int, bool&)

      70.14%     0.00%  bitcoin-net      bitcoind             [.] CNetMessage::readData(char const*, unsigned int)
                  |
                  ---CNetMessage::readData(char const*, unsigned int)
                     CNode::ReceiveMsgBytes(char const*, unsigned int, bool&)

      35.52%     0.00%  bitcoin-net      bitcoind             [.] std::vector<char, zero_after_free_allocator<char> >::_M_fill_insert(__gnu_cxx::__normal_iterator<char*, std::vector<char, zero_after_free_allocator<char> > >, unsigned long, char const&)
                  |
                  ---std::vector<char, zero_after_free_allocator<char> >::_M_fill_insert(__gnu_cxx::__normal_iterator<char*, std::vector<char, zero_after_free_allocator<char> > >, unsigned long, char const&)
                     CNetMessage::readData(char const*, unsigned int)
                     CNode::ReceiveMsgBytes(char const*, unsigned int, bool&)

  ...
  ```

Tree-SHA512: 9ac4ceaa88818d5eca00994e8e3c8ad42ae019550d6583972a0a4f7b0c4f61032e3d0c476b4ae58756bc5eb8f8015a19a7fc26c095bd588f31d49a37ed0c6b3e
2019-02-05 17:40:16 -05:00
..
2018-12-29 10:26:00 +01:00
2018-10-19 01:13:57 +03:00
2019-01-18 10:25:14 +02:00
2018-12-11 22:24:09 +01:00
2018-12-20 21:59:56 +00:00
2016-10-04 13:27:38 +02:00

Bitcoin Core

Setup

Bitcoin Core is the original Bitcoin client and it builds the backbone of the network. It downloads and, by default, stores the entire history of Bitcoin transactions, which requires a few hundred gigabytes of disk space. Depending on the speed of your computer and network connection, the synchronization process can take anywhere from a few hours to a day or more.

To download Bitcoin Core, visit bitcoincore.org.

Running

The following are some helpful notes on how to run Bitcoin Core on your native platform.

Unix

Unpack the files into a directory and run:

  • bin/bitcoin-qt (GUI) or
  • bin/bitcoind (headless)

Windows

Unpack the files into a directory, and then run bitcoin-qt.exe.

macOS

Drag Bitcoin Core to your applications folder, and then run Bitcoin Core.

Need Help?

Building

The following are developer notes on how to build Bitcoin Core on your native platform. They are not complete guides, but include notes on the necessary libraries, compile flags, etc.

Development

The Bitcoin repo's root README contains relevant information on the development process and automated testing.

Resources

Miscellaneous

License

Distributed under the MIT software license. This product includes software developed by the OpenSSL Project for use in the OpenSSL Toolkit. This product includes cryptographic software written by Eric Young (eay@cryptsoft.com), and UPnP software written by Thomas Bernard.