The ThreadID is ID of the thread holding the lock. You can get the list of threads asking for the lock by looking at every thread in the process, and checking whether it is sitting inside the lock helper function.
-Jan -----Original Message----- From: Discussion of the Rotor Shared Source CLI implementation [mailto:[EMAIL PROTECTED] On Behalf Of Sriram Krishnan Sent: Saturday, October 16, 2004 11:59 PM To: [EMAIL PROTECTED] Subject: Re: [DOTNET-ROTOR] Explanation of AwareLock's m_MonitorHeld Thanks for the info! Now, since I know that there is some thread waiting on that lock, can I somehow find out *which* thread it is from sos? From a quick reading of the source, this doesn't seem to be possible as threads that ask for a lock don't seem to be recorded anywhere - just the number of threads is stored in the counter. Am I missing something? This would come in handy for debugging deadlocks in production apps Sriram ------------------------------------------------------------------------ ---- - I blog at http://www.dotnetjunkies.com/weblog/sriram ------------------------------------------------------------------------ ---- > -----Original Message----- > From: Discussion of the Rotor Shared Source CLI > implementation [mailto:[EMAIL PROTECTED] On > Behalf Of Jan Kotas > Sent: 17 October 2004 12:06 > To: [EMAIL PROTECTED] > Subject: Re: [DOTNET-ROTOR] Explanation of AwareLock's m_MonitorHeld > > > 1. Why is the number bumped up by 2 every time someone waits on the > lock? > > This field is a combination of a bit flag and counter. The > bit flag is the lowest bit, the counter is the rest. > > > 2. What is the meaning of doing (state - 2) | 1) - and why? > > This decrements the counter and sets the flag. > > > 3. How do I translate the MonitorHeld column in the > !SyncBlk command? > Do I > assume that every 2 incrememnt after 1 corresponds to some > guy waiting? > > Correct. > > > -Jan > > -----Original Message----- > From: Discussion of the Rotor Shared Source CLI > implementation [mailto:[EMAIL PROTECTED] On > Behalf Of Sriram Krishnan > Sent: Saturday, October 16, 2004 11:32 PM > To: [EMAIL PROTECTED] > Subject: [DOTNET-ROTOR] Explanation of AwareLock's m_MonitorHeld > > While debugging with the SOS extension, I used the SyncBlk > command and got the following output. > 0:003> !SyncBlk > Index SyncBlock MonitorHeld Recursion Thread ThreadID Object > Waiting > 3 0016f634 3 1 161a50 910 4 00aa1bac > System.Object > Waiting threads: > 4 0016f660 3 1 161888 d08 3 00aa1ba0 > System.Object > Waiting threads: > > I was curious to know what that MonitorHeld column was - and > dug through the Rotor sos code and found that it mapped to > the m_MonitorHeld of AwareLock. > > The lines of code that interest me are (in SyncBlk.cpp) > > FastInterlockCompareExchange((LONG*)&m_MonitorHeld, state + > 2, state) (which gets executed whenever tries to acquire a lock) > > And > > FastInterlockCompareExchange((LONG*)&m_MonitorHeld, state - > 2, state) (inside AwareLock::EnterEpilog) > > Whenever you get a new guy waiting on the lock, the state > variable (which is the same as the m_MonitorHeld) gets bumped > up by 2 and bumped back down by 2 whenever someone stops waiting. > > When someone *does* acquire the lock, the code executed is > (FastInterlockCompareExchange((LONG*)&m_MonitorHeld, ((state > - 2) | 1), state). > > Now, here are my questions > > 1. Why is the number bumped up by 2 every time someone waits > on the lock? > > 2. What is the meaning of doing (state - 2) | 1) - and why? > > 3. How do I translate the MonitorHeld column in the !SyncBlk > command? Do I assume that every 2 incrememnt after 1 > corresponds to some guy waiting? > > > Thanks in advance, > Sriram > > > -------------------------------------------------------------- > ---------- > ---- > - > > I blog at http://www.dotnetjunkies.com/weblog/sriram > > -------------------------------------------------------------- > ---------- > ---- > > =================================== > This list is hosted by DevelopMentor(r) > http://www.develop.com ASP.NET courses you may be interested in: > > Guerrilla.NET Sept 27-Oct 1, in Torrance > http://www.develop.com/courses/gdotnetls > > Essential.NET Sept 20-24, in San Francisco Essential.NET Oct. > 4-8, in London http://www.develop.com/courses/edotnet > > > View archives and manage your subscription(s) at > http://discuss.develop.com > > =================================== > This list is hosted by DevelopMentor. http://www.develop.com > ASP.NET courses you may be interested in: > > Guerrilla.NET Sept 27-Oct 1, in Torrance > http://www.develop.com/courses/gdotnetls > > Essential.NET Sept 20-24, in San Francisco Essential.NET Oct. > 4-8, in London http://www.develop.com/courses/edotnet > > > View archives and manage your subscription(s) at > http://discuss.develop.com > =================================== This list is hosted by DevelopMentor(r) http://www.develop.com ASP.NET courses you may be interested in: Guerrilla.NET Sept 27-Oct 1, in Torrance http://www.develop.com/courses/gdotnetls Essential.NET Sept 20-24, in San Francisco Essential.NET Oct. 4-8, in London http://www.develop.com/courses/edotnet View archives and manage your subscription(s) at http://discuss.develop.com =================================== This list is hosted by DevelopMentorŪ http://www.develop.com ASP.NET courses you may be interested in: Guerrilla.NET Sept 27-Oct 1, in Torrance http://www.develop.com/courses/gdotnetls Essential.NET Sept 20-24, in San Francisco Essential.NET Oct. 4-8, in London http://www.develop.com/courses/edotnet View archives and manage your subscription(s) at http://discuss.develop.com
