Move resource determination code to its own file

src/ParallelTestRunner.jl

@@ -32,35 +32,8 @@ include("records.jl")
 include("history.jl")
 using .TestHistory
 
-# Always set the max rss so that if tests add large global variables
-#  (which they do) we don't make the GC's life too hard. Apple's memory
-#  management makes setting this value more complicated than it should
-function get_max_worker_rss()
-    mb = if haskey(ENV, "JULIA_TEST_MAXRSS_MB")
-        parse(Int, ENV["JULIA_TEST_MAXRSS_MB"])
-    elseif Sys.WORD_SIZE == 64
-        totalmem = Sys.total_memory()
-        if Sys.isapple()
-            if totalmem <= 8*Int64(2)^30
-                2000
-            elseif totalmem <= 16*Int64(2)^30
-                2500
-            else
-                3800
-            end
-        elseif totalmem > 8*Int64(2)^30
-            3800
-        else # Low memory not on macOS
-            3000
-        end
-    else
-        # Assume that we only have 3.5GB available to a single process, and that a single
-        # test can take up to 2GB of RSS.  This means that we should instruct the test
-        # framework to restart any worker that comes into a test set with 1.5GB of RSS.
-        1536
-    end
-    return mb * 2^20
-end
+# get_max_worker_rss, DEFAULT_MEMORY_PER_WORKER, default_njobs
+include("resources.jl")
 
 
 #
@@ -355,29 +328,6 @@ function runtest(RecordType::Type{<:AbstractTestRecord}, f, name, init_code, sta
     end
 end
 
-# Assumed memory footprint of a single test worker, used to clamp the default
-# number of jobs on memory-constrained machines (e.g. many cores but little
-# memory). Packages whose tests are heavier can pass a larger
-# `memory_per_worker` to `runtests`.
-const DEFAULT_MEMORY_PER_WORKER = 2 * Int64(2)^30
-
-"""
-    default_njobs(; memory_per_worker = 2 * 2^30)
-
-A function used to determine the default number of parallel jobs. Calculated as the
-number of CPU threads, clamped such that each worker can be assumed to use `memory_per_worker`
-bytes of the available system memory.
-"""
-function default_njobs(;
-        memory_per_worker = DEFAULT_MEMORY_PER_WORKER,
-        # Just use Sys.EFFECTIVE_CPU_THREADS when min VERSION >= v"1.13"
-        _cpu_threads = (@static isdefined(Sys, :EFFECTIVE_CPU_THREADS) ? Sys.EFFECTIVE_CPU_THREADS : Sys.CPU_THREADS),
-        _free_memory = available_memory(),
-    )
-    memory_jobs = Int64(_free_memory) ÷ memory_per_worker
-    return max(1, min(_cpu_threads, memory_jobs))
-end
-
 """
     runtests(mod::Module, args::Union{ParsedArgs,Array{String}};
              testsuite::Dict{String,Expr}=find_tests(pwd()),

src/resources.jl

@@ -0,0 +1,54 @@
+# Memory and job-count sizing for test workers
+
+# Always set the max rss so that if tests add large global variables
+#  (which they do) we don't make the GC's life too hard. Apple's memory
+#  management makes setting this value more complicated than it should
+function get_max_worker_rss()
+    mb = if haskey(ENV, "JULIA_TEST_MAXRSS_MB")
+        parse(Int, ENV["JULIA_TEST_MAXRSS_MB"])
+    elseif Sys.WORD_SIZE == 64
+        totalmem = Sys.total_memory()
+        if Sys.isapple()
+            if totalmem <= 8*Int64(2)^30
+                2000
+            elseif totalmem <= 16*Int64(2)^30
+                2500
+            else
+                3800
+            end
+        elseif totalmem > 8*Int64(2)^30
+            3800
+        else # Low memory not on macOS
+            3000
+        end
+    else
+        # Assume that we only have 3.5GB available to a single process, and that a single
+        # test can take up to 2GB of RSS.  This means that we should instruct the test
+        # framework to restart any worker that comes into a test set with 1.5GB of RSS.
+        1536
+    end
+    return mb * 2^20
+end
+
+# Assumed memory footprint of a single test worker, used to clamp the default
+# number of jobs on memory-constrained machines (e.g. many cores but little
+# memory). Packages whose tests are heavier can pass a larger
+# `memory_per_worker` to `runtests`.
+const DEFAULT_MEMORY_PER_WORKER = 2 * Int64(2)^30
+
+"""
+    default_njobs(; memory_per_worker = 2 * 2^30)
+
+A function used to determine the default number of parallel jobs. Calculated as the
+number of CPU threads, clamped such that each worker can be assumed to use `memory_per_worker`
+bytes of the available system memory.
+"""
+function default_njobs(;
+        memory_per_worker = DEFAULT_MEMORY_PER_WORKER,
+        # Just use Sys.EFFECTIVE_CPU_THREADS when min VERSION >= v"1.13"
+        _cpu_threads = (@static isdefined(Sys, :EFFECTIVE_CPU_THREADS) ? Sys.EFFECTIVE_CPU_THREADS : Sys.CPU_THREADS),
+        _free_memory = available_memory(),
+    )
+    memory_jobs = Int64(_free_memory) ÷ memory_per_worker
+    return max(1, min(_cpu_threads, memory_jobs))
+end