3 files changed, 59 insertions, 22 deletions
diff --git a/tool/lib/test/jobserver.rb b/tool/lib/test/jobserver.rb
new file mode 100644
index 0000000000..7b889163b0
--- /dev/null
+++ b/tool/lib/test/jobserver.rb
@@ -0,0 +1,47 @@
+module Test
+  module JobServer
+  end
+end
+
+class << Test::JobServer
+  def connect(makeflags = ENV["MAKEFLAGS"])
+    return unless /(?:\A|\s)--jobserver-(?:auth|fds)=(?:(\d+),(\d+)|fifo:((?:\\.|\S)+))/ =~ makeflags
+    begin
+      if fifo = $3
+        fifo.gsub!(/\\(?=.)/, '')
+        r = File.open(fifo, IO::RDONLY|IO::NONBLOCK|IO::BINARY)
+        w = File.open(fifo, IO::WRONLY|IO::NONBLOCK|IO::BINARY)
+      else
+        r = IO.for_fd($1.to_i(10), "rb", autoclose: false)
+        w = IO.for_fd($2.to_i(10), "wb", autoclose: false)
+      end
+    rescue
+      r&.close
+      nil
+    else
+      return r, w
+    end
+  end
+
+  def acquire_possible(r, w, max)
+    return unless tokens = r.read_nonblock(max - 1, exception: false)
+    if (jobs = tokens.size) > 0
+      jobserver, w = w, nil
+      at_exit do
+        jobserver.print(tokens)
+        jobserver.close
+      end
+    end
+    return jobs + 1
+  rescue Errno::EBADF
+  ensure
+    r&.close
+    w&.close
+  end
+
+  def max_jobs(max = 2, makeflags = ENV["MAKEFLAGS"])
+    if max > 1 and (r, w = connect(makeflags))
+      acquire_possible(r, w, max)
+    end
+  end
+end
diff --git a/tool/lib/test/unit.rb b/tool/lib/test/unit.rb
index 7d43e825e1..2663b7b76a 100644
--- a/tool/lib/test/unit.rb
+++ b/tool/lib/test/unit.rb
@@ -19,6 +19,7 @@ require_relative '../envutil'
 require_relative '../colorize'
 require_relative '../leakchecker'
 require_relative '../test/unit/testcase'
+require_relative '../test/jobserver'
 require 'optparse'
 
 # See Test::Unit
@@ -262,27 +263,8 @@ module Test
 
       def non_options(files, options)
         @jobserver = nil
-        makeflags = ENV.delete("MAKEFLAGS")
-        if !options[:parallel] and
-          /(?:\A|\s)--jobserver-(?:auth|fds)=(?:(\d+),(\d+)|fifo:((?:\\.|\S)+))/ =~ makeflags
-          begin
-            if fifo = $3
-              fifo.gsub!(/\\(?=.)/, '')
-              r = File.open(fifo, IO::RDONLY|IO::NONBLOCK|IO::BINARY)
-              w = File.open(fifo, IO::WRONLY|IO::NONBLOCK|IO::BINARY)
-            else
-              r = IO.for_fd($1.to_i(10), "rb", autoclose: false)
-              w = IO.for_fd($2.to_i(10), "wb", autoclose: false)
-            end
-          rescue
-            r.close if r
-            nil
-          else
-            r.close_on_exec = true
-            w.close_on_exec = true
-            @jobserver = [r, w]
-            options[:parallel] ||= 256 # number of tokens to acquire first
-          end
+        if !options[:parallel] and @jobserver = Test::JobServer.connect(ENV.delete("MAKEFLAGS"))
+          options[:parallel] ||= 256 # number of tokens to acquire first
         end
         @worker_timeout = EnvUtil.apply_timeout_scale(options[:worker_timeout] || 1200)
         super
diff --git a/tool/lib/test/unit/assertions.rb b/tool/lib/test/unit/assertions.rb
index 19581fc3ab..0908666166 100644
--- a/tool/lib/test/unit/assertions.rb
+++ b/tool/lib/test/unit/assertions.rb
@@ -128,8 +128,16 @@ module Test
 
       def assert_in_delta exp, act, delta = 0.001, msg = nil
         n = (exp - act).abs
+        loadavg = begin
+          if File.readable?("/proc/loadavg")
+            " (/proc/loadavg=#{File.read("/proc/loadavg").strip})"
+          end
+        rescue StandardError
+          nil
+        end
+        loadavg ||= ""
         msg = message(msg) {
-          "Expected |#{exp} - #{act}| (#{n}) to be <= #{delta}"
+          "Expected |#{exp} - #{act}| (#{n}) to be <= #{delta}#{loadavg}"
         }
         assert delta >= n, msg
       end