test: set par=2 in default config for functional test framework #33485

pull andrewtoth wants to merge 1 commits into bitcoin:master from andrewtoth:par-test changing 1 files +1 −0

andrewtoth commented at 4:09 PM on September 27, 2025: contributor

Depending on the host machine, a default par value can spawn up to 15 script verification threads for each node. Running the functional test suite with default par can exhaust file descriptors or hit other resource limits when many threads are spawned. These threads are mostly idle and the same code paths are executed with a value of par=2. Limit this to 2 for functional tests that do not override the default option.
DrahtBot added the label Tests on Sep 27, 2025
DrahtBot commented at 4:09 PM on September 27, 2025: contributor



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For details see: https://corecheck.dev/bitcoin/bitcoin/pulls/33485.



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ACK pablomartin4btc, l0rinc, maflcko, theStack

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in test/functional/test_framework/util.py:477 in 164a1fe956
```
 473 | @@ -474,6 +474,7 @@ def write_config(config_path, *, n, chain, extra_config="", disable_autoconnect=
 474 |          #  min_required_fds = MIN_CORE_FDS + MAX_ADDNODE_CONNECTIONS + nBind = 151 + 8 + 3 = 162;
 475 |          #  nMaxConnections = available_fds - min_required_fds = 256 - 161 = 94;
 476 |          f.write("maxconnections=94\n")
 477 | +        f.write("par=2\n")
```
furszy commented at 7:12 PM on September 27, 2025:

What about min(2, os.cpu_count()) to avoid forcing a second thread when only one core is available.

andrewtoth commented at 7:16 PM on September 27, 2025:

Is there a realistic case where only one core is available?

furszy commented at 8:05 PM on September 27, 2025:

Only the rpi zero comes to mind. It seems like a simple change anyway. I wouldn’t overthink it too much.

l0rinc commented at 8:16 PM on September 27, 2025:

Or maybe a dockerized container

andrewtoth commented at 8:31 PM on September 27, 2025:

Done!

Type	Reviewers
ACK	pablomartin4btc, l0rinc, maflcko, theStack

test: set par=2 in default config for functional test framework

Depending on the host machine, a default `par` value can spawn up to 15 script verification threads for each node.
Running the functional test suite with default `par` can exhaust file descriptors or hit other resource limits when many threads are spawned.
These threads are mostly idle and the same code paths are executed with a value of `par=2`.
Limit this to 2 for functional tests that do not override the default option.

Co-authored-by: maflcko <6399679+maflcko@users.noreply.github.com>

dda5228e02

andrewtoth force-pushed on Sep 27, 2025
pablomartin4btc commented at 9:08 PM on September 27, 2025: member

ACK dda5228e02ca6a839bf87ae7dbd133547563816a

I thought some of the top longest tests would require a diff (>) par=, but it looks alright.
l0rinc approved
l0rinc commented at 12:33 AM on September 28, 2025: contributor

Code review ACK dda5228e02ca6a839bf87ae7dbd133547563816a

Q: does this affect the "-par=1" cases in https://github.com/bitcoin/bitcoin/blob/9a04635432183c437829339dbf10e7d702581010/test/functional/p2p_segwit.py#L221 and https://github.com/bitcoin/bitcoin/blob/6980852416040bdddf111df3cea3ec50639f010a/test/functional/feature_proxy.py#L385?
andrewtoth commented at 12:40 PM on September 28, 2025: contributor

Q: does this affect the "-par=1" cases

No, extra args override args in the configuration file.
maflcko commented at 6:30 AM on September 29, 2025: member

lgtm ACK dda5228e02ca6a839bf87ae7dbd133547563816a
theStack approved
theStack commented at 5:36 PM on September 29, 2025: contributor

ACK dda5228e02ca6a839bf87ae7dbd133547563816a
fanquake merged this on Oct 3, 2025
fanquake closed this on Oct 3, 2025
TheCharlatan referenced this in commit 3f14dd4b2a on Oct 7, 2025
TheCharlatan referenced this in commit 5f9d179b8d on Oct 8, 2025
TheCharlatan referenced this in commit 845b93d99e on Oct 8, 2025
yuvicc referenced this in commit ccce70c31a on Oct 8, 2025
TheCharlatan referenced this in commit 3b1e26d5d3 on Oct 10, 2025
TheCharlatan referenced this in commit 0fa2fdaca0 on Oct 11, 2025
stringintech referenced this in commit f74b275ffc on Oct 14, 2025
andrewtoth deleted the branch on Oct 16, 2025

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test: set par=2 in default config for functional test framework #33485

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