3rd-party/catch2
1
0
Fork 0
mirror of https://github.com/catchorg/Catch2.git synced 2025-08-02 21:35:40 +02:00
Code Issues Packages Projects Releases Wiki Activity

Add configuration option to make assertions thread-safe

Browse Source 
All the previous refactoring to make the assertion fast paths
smaller and faster also allows us to implement the fast paths
just with thread-local and atomic variables, without full mutexes.

However, the performance overhead of thread-safe assertions is
still significant for single threaded usage:

|  slowdown |  Debug  | Release |
|-----------|--------:|--------:|
| fast path |   1.04x |   1.43x |
| slow path |   1.16x |   1.22x |

Thus, we don't make the assertions thread-safe by default, and instead
provide a build-time configuration option that the users can set to get
thread-safe assertions.

This commit is functional, but it still needs some follow-up work:
 * We do not need full seq_cst increments for the atomic counters,
   and using weaker ones can be faster.
 * We brute-force updating the reporter-friendly totals from internal
   atomic counters by doing it everywhere. We should properly trace
   where this is needed instead.
 * Message macros (`INFO`, `UNSCOPED_INFO`, `CAPTURE`, etc) are not
   made thread safe in this commit, but they can be made thread safe
   in the future, by building on top of this work.
 * Add more tests, including with thread-sanitizer, and compiled
   examples to the repository. Right now, these changes have been
   compiled with tsan manually, but these tests are not added to CI.

Closes #2948
This commit is contained in:
Martin Hořeňovský
2025-07-17 22:58:41 +02:00
parent 900a6d5516
commit 2a8a8a7210
12 changed files with 332 additions and 49 deletions
Download Patch File Download Diff File Expand all files Collapse all files

17
docs/configuration.md
View File

@@ -14,8 +14,10 @@
[Other toggles](#other-toggles)<br>
[Enabling stringification](#enabling-stringification)<br>
[Disabling exceptions](#disabling-exceptions)<br>
[Disabling deprecation warnings](#disabling-deprecation-warnings)<br>
[Overriding Catch's debug break (`-b`)](#overriding-catchs-debug-break--b)<br>
[Static analysis support](#static-analysis-support)<br>
[Experimental thread safety](#experimental-thread-safety)<br>
Catch2 is designed to "just work" as much as possible, and most of the
configuration options below are changed automatically during compilation,
@@ -314,6 +316,21 @@ no backwards compatibility guarantees._
are not meant to be runnable, only "scannable".
## Experimental thread safety
> Introduced in Catch2 X.Y.Z
Catch2 can optionally support thread-safe assertions, that means, multiple
user-spawned threads can use the assertion macros at the same time. Due
to the performance cost this imposes even on single-threaded usage, Catch2
defaults to non-thread-safe assertions.
CATCH_CONFIG_EXPERIMENTAL_THREAD_SAFE_ASSERTIONS // enables thread safe assertions
CATCH_CONFIG_NO_EXPERIMENTAL_THREAD_SAFE_ASSERTIONS // force-disables thread safe assertions
See [the documentation on thread safety in Catch2](thread-safety.md#top)
for details on which macros are safe and other notes.
---