[ python-Bugs-1484172 ] hyper-threading locks up sleeping threads

[SourceForge.net]

Bugs item #1484172, was opened at 2006-05-08 17:45
Message generated for change (Comment added) made by tim_one
You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1484172&group_id=5470

Please note that this message will contain a full copy of the comment thread,
including the initial issue submission, for this request,
not just the latest update.
Category: Threads
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Olaf Meding (olafmeding)
Assigned to: Nobody/Anonymous (nobody)
Summary: hyper-threading locks up sleeping threads

Initial Comment:
Below are 2 files.  The first is a Python program that 
demonstrates the problem within less than 1 hour 
(often just a few minutes).  The second is a C++ 
program that shows that the Win32 Sleep() function 
works as expected (the program was started 3 days ago 
and is still running).

Note, I also attached the source code.

Note, the Python programs hangs (stops responding) 
with hyper-threading turned on (a BIOS setting), but 
works as expected with hyper-threading turned off.

This problem happens on Windows only (the below Python 
program ran for 24 hours on Linux without a problem).

Variations of the Python program also lock up:

Tried importing win32api instead of importing time and 
using the win32api.GetTickCount() and win32api.Sleep() 
methods.

Tried using lock = threading.Event() and lock.wait() 
instead of time.sleep().

Tried importing Queue and using q = Queue.Queue() and 
q.get(True, sleepTime).

Note, the Windows task manager shows 2 CPUs on the 
Performance tab with hyper-threading is turned on.

Both Python 2.3.5 and 2.4.3 (downloaded from 
python.org) have this problem.

The operating system is MS Windows XP Professional.

winmsd.exe (Start Menu > Run) shows:
2CPUs: x86 Family 15 Model 4 Stepping 1 GenuineIntel 
~3000 MHz
Version: 5.1.2600 Service Pack 2 Build 2600

Could someone with a hyper-threading (or dual-core or 
multi-processor) CPU please confirm this bug?

Many Thanks

Olaf


Here is the expected output of both programs (the 
progam has locked up if the numbers stop printing 
every 10 seconds or so):
python testsleep.py
thread 1 started, sleep time 0.010
thread 2 started, sleep time 0.003
1 1 1 2 1 1 1 2 1 1 1 2 1 1 1 1 2 1 1 1

# testsleep.py
import threading
import time

class Task(threading.Thread):
        def __init__(self, n, t):
                threading.Thread.__init__(self)
                self.n = n  # thread id
                self.t = t  # sleep time
        def run(self):
                print 'thread %d started, sleep time 
%.3f' % (self.n, self.t)
                count = 0
                printCount = int(10 / self.t)
                while True:
                        start = time.clock()
                        time.sleep(self.t)
                        stop = time.clock()
                        if stop - start > 1.0:
                                print 'thread', 
self.n, stop - start

                        count += 1
                        if count > printCount:
                                count = 0
                                print self.n,  # print 
sign of live

def test():
        thread1 = Task(1, 0.01)  # thread 1, sleep 10 
ms
        thread2 = Task(2, 0.003) # thread 2, sleep  3 
ms
        thread1.start()
        thread2.start()

test()

-------------------------------------------------------
---------------------------

// testsleep.cpp
// Compiled with Visual C++ version 6 (in debug mode) 
as a Win32 console application.

#include <windows.h>
#include <stdio.h>
#include <time.h>

typedef struct {
    int id;
    int ms;

} param_s;

DWORD WINAPI threadFunction(LPVOID param)
{
    param_s* p = (param_s*)param;
    long elapsedTime;
    long time1, time2;
    long printCount = long(10000 / p->ms);  // loop 
iterations in 10 seconds
    long count = 0;

    printf("thread %d started, sleep time: %d 
ms" "\n", p->id, p->ms);

    while(true) {
        time1 = GetTickCount();
        Sleep(p->ms);
        time2 = GetTickCount();

        elapsedTime = time2 - time1;
        if(elapsedTime > 1000)
            printf("thread %d slept for %d ms" "\n", p-
>id, elapsedTime);

        count++;
        if(count > printCount) {
            count = 0;
            printf("%d ", p->id);  // print sign of 
live
        }
    }

    return 0;
}

int main(int argc, char* argv[])
{
    param_s p1, p2;

    p1.id = 1;
    p1.ms = 10;

    p2.id = 2;
    p2.ms = 3;

    CreateThread(NULL, 0, threadFunction, (void*)&p1, 
0, NULL);
    CreateThread(NULL, 0, threadFunction, (void*)&p2, 
0, NULL);

    getchar();  // wait until the user presses the 
enter key.

    return 0; 
}

----------------------------------------------------------------------

>Comment By: Tim Peters (tim_one)
Date: 2006-05-08 17:58

Message:
Logged In: YES 
user_id=31435

As noted (multiple times by now ;-)) on c.l.py, the Python
program does not hang on my similar HT box:

http://mail.python.org/pipermail/python-list/2006-May/340538.html


----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=1484172&group_id=5470