nthreads() -> nthreads(threadpool)

CHANGELOG.md

@@ -5,6 +5,7 @@ Version 0.4.0
 -------------
 
 - ![BREAKING][badge-breaking] Instead of taking keyword arguments `schedule`, `nchunks`, `split` directly, we now use `Scheduler` structs to specify scheduling options ([#22](https://github.com/JuliaFolds2/OhMyThreads.jl/issues/22)). The latter can be provided to all API functions via the new `scheduler` keyword argument.
+- ![BREAKING][badge-breaking] The default scheduler (`DynamicScheduler`) now, by default, creates `2*nthreads()` tasks to provide load-balancing by default. The old behavior can be restored with `DynamicScheduler(nchunks=nthreads())`.
 - ![Enhancement][badge-enhancement] We reject unsupported keyword arguments early and give a more helpful error message.
 
 Version 0.3.1

src/schedulers.jl

@@ -22,7 +22,7 @@ with other multithreaded code.
 
 ## Keyword arguments:
 
-- `nchunks::Int` (default `2 * nthreads()`):
+- `nchunks::Int` (default `2 * nthreads(threadpool)`):
     * Determines the number of chunks (and thus also the number of parallel tasks).
     * Increasing `nchunks` can help with [load balancing](https://en.wikipedia.org/wiki/Load_balancing_(computing)), but at the expense of creating more overhead. For `nchunks <= nthreads()` there are not enough chunks for any load balancing.
     * Setting `nchunks < nthreads()` is an effective way to use only a subset of the available threads.
@@ -34,14 +34,14 @@ with other multithreaded code.
     * The high-priority pool `:interactive` should be used very carefully since tasks on this threadpool should not be allowed to run for a long time without `yield`ing as it can interfere with [heartbeat](https://en.wikipedia.org/wiki/Heartbeat_(computing)) processes.
 """
 Base.@kwdef struct DynamicScheduler <: Scheduler
-    nchunks::Int = 2 * nthreads() # a multiple of nthreads to enable load balancing
-    split::Symbol = :batch
     threadpool::Symbol = :default
+    nchunks::Int = 2 * nthreads(threadpool) # a multiple of nthreads to enable load balancing
+    split::Symbol = :batch
 
-    function DynamicScheduler(nchunks::Int, split::Symbol, threadpool::Symbol)
-        nchunks > 0 || throw(ArgumentError("nchunks must be a positive integer"))
+    function DynamicScheduler(threadpool::Symbol, nchunks::Int, split::Symbol)
         threadpool in (:default, :interactive) ||
             throw(ArgumentError("threadpool must be either :default or :interactive"))
+        nchunks > 0 || throw(ArgumentError("nchunks must be a positive integer"))
         new(nchunks, split, threadpool)
     end
 end