www.digitalmars.com         C & C++   DMDScript  

digitalmars.D.bugs - [Issue 1828] New: Several Thread Issues

reply d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1828

           Summary: Several Thread Issues
           Product: D
           Version: 2.010
          Platform: PC
        OS/Version: Windows
            Status: NEW
          Keywords: patch
          Severity: normal
          Priority: P2
         Component: DMD
        AssignedTo: bugzilla digitalmars.com
        ReportedBy: kinaba is.s.u-tokyo.ac.jp


// Credit goes to http://pc11.2ch.net/test/read.cgi/tech/1202623572/30-35n

There are several problems in std.thread.
Please find attached the patch to fix all of them.

1. Thread.start

 state = TS.RUNNING;
 hdl = _beginthreadex(null, cast(uint)stacksize, &threadstart, cast(void*)this,
0, &id);


  If context-switch occurs between these two lines,
  thread which acutually is not running is treated as TS.RUNNING.
  This causes problems, for example in pauseAll().
  So these lines should be property synchronized.


 if (hdl == cast(thread_hdl)0)


  When _beginthreadex fails and this branch is taken,
  the variable nthread should be decremented.

2. std.wait timeouts
  When a call to wait() timeouts (not fails),
  > dw = WaitForSingleObject(hdl, 0xFFFFFFFF);
  > state = TS.FINISHED;
  the current implemetation treats it as it fails.
  But in this case, the thread is indeed still alive and may wake up again
  just after the "state = TS.FINISHED" statement. If that happens,
  pauseAll() do not stop the thread (because it's TS.FINISHED) and
  multiple threads may unintendedly run parallel.
  This IS a problem for std.gc, which is relying on the assumption that
  pauseAll() stops all but gc threads.

3. Priority
  It is convenient if one can set the NORMAL thread priority.


--
Feb 11 2008
next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1828






Created an attachment (id=226)
 --> (http://d.puremagic.com/issues/attachment.cgi?id=226&action=view)
Patch to fix the issue


--
Feb 11 2008
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1828


sjguy cs.unc.edu changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |sjguy cs.unc.edu





I applied this patch and it fixed an issue I was having.  My program would
eventually crash with either a "Win32 Error" or a "Error: Cannot Pause" error. 
This seemed to happen when my compute intensive threads were garbage collected,
presumable for the exact reason Kazuhiro Inaba stated.

Since recompiling Phobos with this patch, I have not encountered either error.


--
Feb 28 2008
prev sibling next sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1828


spam extrawurst.org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |spam extrawurst.org
           Severity|normal                      |critical





pretty please apply this patch in the next release. i am encountering these
mutlithreading crashes due to the GC, too.


--
Feb 28 2008
prev sibling parent d-bugmail puremagic.com writes:
http://d.puremagic.com/issues/show_bug.cgi?id=1828


bugzilla digitalmars.com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED





Fixed dmd 1.028 and 2.012 (and thanks for sorting this out)


--
Mar 06 2008