Mutex Try-Lock Coordination Report

Attempt a nonblocking mutex acquisition a fixed number of times and report whether the guard stayed open or blocked a later attempt.

Mutex Try-Lock Coordination Report

mutex_try_lock_coordination_report.rb

holds = 
guard = Mutex.new
acquired = 0
blocked = 0

holds.times do
  if guard.try_lock
    acquired += 1
  else
    blocked += 1
  end
end

guard.unlock if guard.locked?

status = if acquired == 0
  "open"
elsif blocked > 0
  "blocked"
else
  "guarded"
end

puts "holds=#{holds}"
puts "acquired=#{acquired}"
puts "blocked=#{blocked}"
puts "status=#{status}"

holds = 
guard = Mutex.new
acquired = 0
blocked = 0

holds.times do
  if guard.try_lock
    acquired += 1
  else
    blocked += 1
  end
end

guard.unlock if guard.locked?

status = if acquired == 0
  "open"
elsif blocked > 0
  "blocked"
else
  "guarded"
end

puts "holds=#{holds}"
puts "acquired=#{acquired}"
puts "blocked=#{blocked}"
puts "status=#{status}"

holds = 
guard = Mutex.new
acquired = 0
blocked = 0

holds.times do
  if guard.try_lock
    acquired += 1
  else
    blocked += 1
  end
end

guard.unlock if guard.locked?

status = if acquired == 0
  "open"
elsif blocked > 0
  "blocked"
else
  "guarded"
end

puts "holds=#{holds}"
puts "acquired=#{acquired}"
puts "blocked=#{blocked}"
puts "status=#{status}"

nonblocking mutex `Mutex#try_lock` returns `true` when it takes the lock and `false` when the guard is already held, so a second attempt that fails reports that the mutex is not reentrant and the section is busy.