Skip to content

Clarify the guarantees on the number of IO threads #4578

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
dkhalanskyjb wants to merge 1 commit into
base: develop
Choose a base branch
from
+4 −2
Open

Clarify the guarantees on the number of IO threads #4578

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 4 additions & 2 deletions kotlinx-coroutines-core/jvm/src/Dispatchers.kt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -57,8 +57,10 @@ public actual object Dispatchers {
* dispatcher typically does not lead to an actual switching to another thread. In such scenarios,
* the underlying implementation attempts to keep the execution on the same thread on a best-effort basis.
*
* As a result of thread sharing, more than 64 (default parallelism) threads can be created (but not used)
* during operations over IO dispatcher.
* Whenever we are talking about the number of IO threads in the pool being limited by some number,
* that only means that at most that many threads are going to *actually perform* IO work in parallel.
Comment on lines +60 to +61
Copy link
Contributor

@murfel murfel Dec 1, 2025

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Possibly make it more formal, by getting rid of "we"

"The number of IO threads is at most N" means that at most N threads...

* It is still possible to observe more threads than that, but those threads are guaranteed to be in their
* start-up or shutdown phases.
*/
@JvmStatic
public val IO: CoroutineDispatcher get() = DefaultIoScheduler
Expand Down