add dedicated IO thread (capability only) #53422
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
function make_io_thread()
tid = UInt[0]
threadwork = @cfunction function(arg::Ptr{Cvoid})
@CCall jl_set_io_loop_tid((Threads.threadid() - 1)::Int16)::Cvoid
wait() # spin uv_run as long as needed
nothing
end Cvoid (Ptr{Cvoid},)
err = @CCall uv_thread_create(tid::Ptr{UInt}, threadwork::Ptr{Cvoid}, C_NULL::Ptr{Cvoid})::Cint
err == 0 || Base.uv_error("uv_thread_create", err)
tid[]
end
vtjnash
added
the
domain:io
vtjnash
added
the
status:merge me
|
I don't really trust threading to be stable enough to run a test for it. Gabriel has an existing PR to fix some of the threading bugs, so this PR is really only intended to help someone in the future to implement this by providing an example. |
inkydragon
removed
the
status:merge me
|
Is this a minor enough change with a NFC default state to backport to 1.11 as experimental & undocumented? |
tecosaur
pushed a commit
to tecosaur/julia
that referenced
this pull request
Mar 4, 2024
It has been oft-requested that we have a dedicated IO thread. That
actually turns out to already be the case of something that exists,
except that we hard-code the identity of that thread as being thread 0.
This PR replaces all of the places where we hard code that assumption
with a variable so that they are more easily searched for in the code.
It also adds an internal function (`jl_set_io_loop_tid`) that can be
used to transfer ownership of the loop to any (valid) tid. In
conjunction with the prior foreign-threads work and foreign-thread pool,
this lets us spawn a dedicate IO-management thread with this bit of
code:
```julia
function make_io_thread()
tid = UInt[0]
threadwork = @cfunction function(arg::Ptr{Cvoid})
Base.errormonitor(current_task()) # this may not go particularly well if the IO loop is dead, but try anyways
@CCall jl_set_io_loop_tid((Threads.threadid() - 1)::Int16)::Cvoid
wait() # spin uv_run as long as needed
nothing
end Cvoid (Ptr{Cvoid},)
err = @CCall uv_thread_create(tid::Ptr{UInt}, threadwork::Ptr{Cvoid}, C_NULL::Ptr{Cvoid})::Cint
err == 0 || Base.uv_error("uv_thread_create", err)
@CCall uv_thread_detach(tid::Ptr{UInt})::Cint
err == 0 || Base.uv_error("uv_thread_detach", err)
# n.b. this does not wait for the thread to start or to take ownership of the event loop
nothing
end
```
JeffBezanson
added
the
domain:multithreading
mkitti
pushed a commit
to mkitti/julia
that referenced
this pull request
Mar 7, 2024
It has been oft-requested that we have a dedicated IO thread. That
actually turns out to already be the case of something that exists,
except that we hard-code the identity of that thread as being thread 0.
This PR replaces all of the places where we hard code that assumption
with a variable so that they are more easily searched for in the code.
It also adds an internal function (`jl_set_io_loop_tid`) that can be
used to transfer ownership of the loop to any (valid) tid. In
conjunction with the prior foreign-threads work and foreign-thread pool,
this lets us spawn a dedicate IO-management thread with this bit of
code:
```julia
function make_io_thread()
tid = UInt[0]
threadwork = @cfunction function(arg::Ptr{Cvoid})
Base.errormonitor(current_task()) # this may not go particularly well if the IO loop is dead, but try anyways
@CCall jl_set_io_loop_tid((Threads.threadid() - 1)::Int16)::Cvoid
wait() # spin uv_run as long as needed
nothing
end Cvoid (Ptr{Cvoid},)
err = @CCall uv_thread_create(tid::Ptr{UInt}, threadwork::Ptr{Cvoid}, C_NULL::Ptr{Cvoid})::Cint
err == 0 || Base.uv_error("uv_thread_create", err)
@CCall uv_thread_detach(tid::Ptr{UInt})::Cint
err == 0 || Base.uv_error("uv_thread_detach", err)
# n.b. this does not wait for the thread to start or to take ownership of the event loop
nothing
end
```
|
FWIW, the example given above currently reliably |
|
It does not segfault, but the |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
It has been oft-requested that we have a dedicated IO thread. That actually turns out to already be the case of something that exists, except that we hard-code the identity of that thread as being thread 0. This PR replaces all of the places where we hard code that assumption with a variable so that they are more easily searched for in the code. It also adds an internal function (
jl_set_io_loop_tid) that can be used to transfer ownership of the loop to any (valid) tid. In conjunction with the prior foreign-threads work and foreign-thread pool, this lets us spawn a dedicate IO-management thread with this bit of code: