[Tcl-Threads] Threads preemption - big problem - continued

[Krzysztof F. <fru...@gm...>]

Hello again,

I was trying to solve the problem from my previous post using mutex.
But it does not seem to work.
Blow is the code. Senders, one worker.

package require Thread

tsv::set threads worker [thread::create]
tsv::set threads sender1 [thread::create]
tsv::set threads sender2 [thread::create]
tsv::set threads sender3 [thread::create]

puts "sender 1: [tsv::get threads sender1]"
puts "sender 2: [tsv::get threads sender2]"
puts "sender 3: [tsv::get threads sender3]"
puts "worker:  [tsv::get threads worker]"

tsv::set db mutex [thread::mutex create]


thread::send [tsv::get threads worker] {
	package require Expect
	set timeout 2
	spawn picocom /home/dib/vmodem0
}

thread::send -async [tsv::get threads sender1] {
	package require Thread
	
	for {set i 0} {$i < 3} {incr i} {
		
		set mutex [tsv::get db mutex]
		thread::mutex lock $mutex
		thread::send -async [tsv::get threads worker] {
			
			puts "Worker IN - from sender1"
			catch {expect {
				"D" {puts "[thread::id] got D"}
				timeout {puts "[thread::id] timedout"}
				}
				
			}
			puts "Worker OUT - from sender1"
		}
		thread::mutex unlock $mutex
		
		::after 1110
	}
}

thread::send -async [tsv::get threads sender2] {
	package require Thread
	
	for {set i 0} {$i < 3} {incr i} {
		
		set mutex [tsv::get db mutex]
		thread::mutex lock $mutex
		thread::send -async [tsv::get threads worker] {
			
			puts "Worker IN - from sender2"
			catch {expect {
				"D" {puts "[thread::id] got D"}
				timeout {puts "[thread::id] timedout"}
					}
							
			}
			puts "Worker OUT - from sender2"
		}
		thread::mutex unlock $mutex
		::after 690
	}
}

thread::send -async [tsv::get threads sender3] {
	package require Thread
	
	for {set i 0} {$i < 3} {incr i} {
		
		set mutex [tsv::get db mutex]
		thread::mutex lock $mutex
		thread::send -async [tsv::get threads worker] {
			
			puts "Worker IN - from sender3"
			catch {expect {
				"D" {puts "[thread::id] got D"}
				timeout {puts "[thread::id] timedout"}
				}
							
			}
			puts "Worker OUT - from sender3"
		}
		thread::mutex unlock $mutex
		
		::after 550
	}
}

puts "main thread done"

thread::wait




An the output:
sender 1: tid0x7f2a8a059700
sender 2: tid0x7f2a89858700
sender 3: tid0x7f2a89057700
worker:  tid0x7f2a8a85a700
spawn picocom /home/dib/vmodem0
main thread done
Worker IN - from sender1
Worker IN - from sender2
Worker IN - from sender3
picocom v1.4

port is        : /home/dib/vmodem0
flowcontrol    : none
baudrate is    : 9600
parity is      : none
databits are   : 8
escape is      : C-a
noinit is      : no
noreset is     : no
nolock is      : no
send_cmd is    : ascii_xfr -s -v -l10
receive_cmd is : rz -vv

Terminal ready
Worker IN - from sender3
Worker IN - from sender2
Worker IN - from sender3
Worker IN - from sender1
Worker IN - from sender2
Worker IN - from sender1
tid0x7f2a8a85a700 timedout
Worker OUT - from sender1
tid0x7f2a8a85a700 timedout
Worker OUT - from sender2
tid0x7f2a8a85a700 timedout
Worker OUT - from sender1
tid0x7f2a8a85a700 timedout
Worker OUT - from sender3
tid0x7f2a8a85a700 timedout
Worker OUT - from sender2
tid0x7f2a8a85a700 timedout
Worker OUT - from sender3
tid0x7f2a8a85a700 timedout
Worker OUT - from sender3
tid0x7f2a8a85a700 timedout
Worker OUT - from sender2
tid0x7f2a8a85a700 timedout
Worker OUT - from sender1

Why does a mutex let several threads in to the critical section?