test: reduce runtime of p2p_opportunistic_1p1c.py #33048

1. 
   glozow commented at 7:23 pm on July 23, 2025: member

   It was brought to my attention that the runtime of this test is Too Damn High. The test is slow due to the many wait_for_getdatas with delays (inbound peer + txid request) and the large volume of messages sent in the dos-related tests. This PR cuts the runtime by about 60% by reducing the number of messages/transactions and using setmocktime instead of waiting.

   On my machine, master:

   084.51s user 1.55s system 57% cpu 2:28.53 total
   

   After first commit (about 1min faster):

   028.29s user 0.88s system 35% cpu 1:22.84 total
   

   After second commit (about 30sec faster):

   028.17s user 0.87s system 59% cpu 49.082 total
   

   Reviewers should verify that the transactions in the DoS tests are still enough to cause evictions, and that the bumpmocktime amounts are not more than necessary.

   Alternatives:

   • If we don’t like mocking the times, we can use outbound connections for all the peers. However, that approach won’t improve the runtime as much because we impose a 2-second delay on all txid requests regardless of peer type.
   • Note that noban_tx_relay is not relevant for this test because all delays are related to downloading, not announcing.
2. [test] cut the number of transactions involved in 1p1c DoS tests

   We just need enough transactions to push us above the orphanage limits
   and trigger trimming. Reducing the number of transactions cuts the
   runtime of this test significantly.

   70772dd469
3. [test] setmocktime instead of waiting in 1p1c tests

   Significantly speed up the runtime of the test.

   eb65f57f31
4. glozow added the label Tests on Jul 23, 2025
5. 
   DrahtBot commented at 7:24 pm on July 23, 2025: contributor

   The following sections might be updated with supplementary metadata relevant to reviewers and maintainers.

   Code Coverage & Benchmarks

   For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33048.

   Reviews

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   Type	Reviewers
   ACK	achow101, w0xlt

   If your review is incorrectly listed, please react with 👎 to this comment and the bot will ignore it on the next update.

6. glozow force-pushed on Jul 23, 2025
7. 
   glozow commented at 7:25 pm on July 23, 2025: member

   cc @achow101
8. 
   achow101 commented at 8:57 pm on July 23, 2025: member

   The runtime is now much better, thanks!

   ACK eb65f57f319dc4e2ea8c83cf7e283c36f1c0d53b

   I checked that the changes looked sane, but did not exhaustively walkthrough the scenarios to determine whether evictions were occurring.

9. 
   w0xlt commented at 8:51 pm on July 24, 2025: contributor

   ACK https://github.com/bitcoin/bitcoin/pull/33048/commits/eb65f57f319dc4e2ea8c83cf7e283c36f1c0d53b

   On my machine, master: 43 s This PR: 27 s

   Even reducing the number of transactions and peer connections used in the DoS portions of the test, it still fills the orphan pool past its limit, ensuring that evictions occur. The use of mock time also makes the test more deterministic.

10. fanquake merged this on Aug 1, 2025
11. fanquake closed this on Aug 1, 2025

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Contributors
glozow DrahtBot achow101 w0xlt

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Tests