Separate foreign threads into a :foreign threadpool #50912
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Won't that only happen if the foreign thread yields though? During that time we might as well use it for other work. I also don't really like having a special-case "threadpool that is not really a threadpool". |
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Yeah I really don't like this as well. I think the question if the foreign thread is yielding Part of the question is what are the semantics of
The problem is that we don't have a real notion of fairness in the scheduler. So it is indeterminate when/if the foreign thread returns. The root task is marked as In particular the comment here motivated me to differentiate between, not in a threadpool and in a threadpool. |
That thread could be considered interactive, but also our own event loop thread is worthy of a special case!
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At least from the perspective of a user I would think that if I called into julia, it would run my function and return. At least as a default behaviour. |
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I was also half thinking of introducing two different categories instead of |
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My concern was that the user might have started Julia with, say, |
Yeah, we do not. We currently associate them with the I think long-term we may want to make pools resizable, but that's a bigger more complicated change. It might make sense to split utility/system threads out, and then we could turn these workloads into tasks for GC sweep, libuv polling, maybe finalizers? GC sweep and finalizers could definitly run on the same thread (except for the fact that we currently don't start one by default.) |
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Co-authored-by: Gabriel Baraldi <[email protected]>
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Co-authored-by: Gabriel Baraldi <[email protected]> Co-authored-by: Dilum Aluthge <[email protected]> (cherry picked from commit 8be469e)
Backported PRs: - [x] #48625 <!-- add replace(io, str, patterns...) --> - [x] #48387 <!-- Improve documentation of sort-related functions --> - [x] #48363 <!-- Revise sort.md and docstrings in sort.jl --> - [x] #48977 <!-- Update SparseArrays.jl stdlib for SuiteSparse 7 --> - [x] #50719 <!-- fix `CyclePadding(::DataType)` --> - [x] #50694 <!-- inference: permit recursive type traits --> - [x] #50860 <!-- Add `Base.get_extension` to docs/API --> - [x] #50594 <!-- Disallow non-index Integer types in isassigned --> - [x] #50802 <!-- Makes IntrusiveLinkedListSynchronized mutable to avoid allocation on poptask --> - [x] #50858 <!-- Add a `threadpool` parameter to `Channel` constructor --> - [x] #50874 <!-- Restrict COFF to a single thread when symbol count is high --> - [x] #50822 <!-- Add default method for setmodifiers! --> - [x] #50730 <!-- Fix integer overflow in `isapprox` --> - [x] #50850 <!-- Remove weird Rational dispatch and add pi functions to list --> - [x] #50809 <!-- Limit type-printing in MethodError --> - [x] #50915 <!-- Add note the `Task` about sticky bit --> - [x] #50929 <!-- when widening tuple types in tmerge, only widen the complex parts --> - [x] #50928 <!-- Bump JuliaSyntax to 0.4.6 --> - [x] #50959 <!-- Update libssh2 patches --> - [x] #50823 <!-- Make ranges more robust with unsigned indexes. --> - [x] #48542 <!-- Add docs on task-specific buffering using multithreading --> - [x] #50912 <!-- Separate foreign threads into a :foreign threadpool --> - [x] #51010 <!-- Add ORIGIN to SuiteSparse rpath on Linux/FreeBSD --> - [x] #50753 <!-- cat: remove unused promote_eltype methods that confuse inference --> - [x] #51027 <!-- Implement realloc accounting correctly --> - [x] #51019 <!-- fix a case of potentially use of undefined variable when handling error in distributed message processing --> - [x] #51039 <!-- Revert "Optimize findall(f, ::AbstractArray{Bool}) (#42202)" --> - [x] #51036 <!-- add missing invoke edge for nospecialize targets --> - [x] #51042 <!-- inference: fix return_type_tfunc modeling of concrete functions --> - [x] #51114 <!-- Workaround upstream FreeBSD issue #272992 --> - [x] #50892 <!-- Add `JL_DLLIMPORT` to `small_typeof` declaration --> - [x] #51154 <!-- broadcast: use recursion rather than ntuple to map over a tuple --> - [x] #51153 <!-- fix debug typo in "add missing invoke edge for nospecialize targets (#51036)" --> - [x] #51222 <!-- Check again if the tty is open inside the IO lock --> - [x] #51236 <!-- Add lock around uv_unref during init --> - [x] #51243 <!-- GMP: Gracefully handle more overflows. --> - [x] #51254 <!-- Ryu: make sure adding zeros does not overwrite trailing dot --> - [x] #51175 <!-- shorten stale_age for cachefile lock --> - [x] #51300 <!-- fix method definition error for bad vararg --> - [x] #51307 <!-- fix force-throw ctrl-C on Windows --> - [x] #51303 <!-- ensure revising structs is safe --> - [x] #51393 - [x] #51403 Need manual backport: - [x] #51009 <!-- fix #50562, regression in `in` of tuple of Symbols --> - [x] #51053 <!-- Bump Statistics stdlib --> - [x] #51013 <!-- fix #50709, type bound error due to free typevar in sparam env --> - [x] #51305 <!-- reduce test time for rounding and floatfuncs --> Contains multiple commits, manual intervention needed: - [ ] #50663 <!-- Fix Expr(:loopinfo) codegen --> - [ ] #51035 <!-- refactor GC scanning code to reflect jl_binding_t are now first class --> - [ ] #51092 <!-- inference: fix bad effects for recursion --> - [x] #51247 <!-- Check if malloc has succeeded before incrementing gc stats --> - [x] #51294 <!-- use LibGit2_jll for LibGit2 library --> Non-merged PRs with backport label: - [ ] #51132 <!-- Handle `AbstractQ` in concatenation --> - [x] #51029 <!-- testdefs: make sure that if a test set changes the active project, they change it back when they're done --> - [ ] #50919 <!-- Code loading: do the "skipping mtime check for stdlib" check regardless of the value of `ispath(f)` --> - [ ] #50824 <!-- Add some aliasing warnings to docstrings for mutating functions --> - [x] #50385 <!-- Precompile pidlocks: add to NEWS and docs --> - [ ] #49805 <!-- Limit TimeType subtraction to AbstractDateTime -->
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Co-authored-by: Gabriel Baraldi <[email protected]> Co-authored-by: Dilum Aluthge <[email protected]> (cherry picked from commit 8be469e)
Co-authored-by: Gabriel Baraldi <[email protected]> Co-authored-by: Dilum Aluthge <[email protected]> (cherry picked from commit 8be469e)
Backported PRs: - [x] #49357 <!-- Fix unclosed code fence in src/manual/methods.md --> - [x] #50842 <!-- Avoid race conditions with recursive rm --> - [x] #50858 <!-- Add a `threadpool` parameter to `Channel` constructor --> - [x] #50730 <!-- Fix integer overflow in `isapprox` --> - [x] #50823 <!-- Make ranges more robust with unsigned indexes. --> - [x] #50915 <!-- Add note the `Task` about sticky bit --> - [x] #50989 <!-- fix incorrect results in `expm1(::Union{Float16, Float32})` --> - [x] #50912 <!-- Separate foreign threads into a :foreign threadpool --> - [x] #51019 <!-- fix a case of potentially use of undefined variable when handling error in distributed message processing --> - [x] #51222 <!-- Check again if the tty is open inside the IO lock --> - [x] #51254 <!-- Ryu: make sure adding zeros does not overwrite trailing dot --> - [x] #51284 <!-- Avoid infinite loop when doing SIGTRAP in arm64-apple --> - [x] #51491 <!-- Throw clearer ArgumentError for strip with two string args --> - [x] #51531 <!-- fix `_tryonce_download_from_cache` (busybox.exe download error) -->
In separate conversation over the last few days with @maleadt and @gbaraldi,
we noticed that foreign threads (or the utility thread in #50880) were used
by the scheduler for unrelated workloads.
Here we separate out the notion of interactive from unassociated.
In particular for foreign threads we should return to the calling foreign code
as soon as possible and not become co-opted into running unrelated workloads.
@asyncstill executes on the parent thread as usual.