-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi,
> I encounter strange problems with semaphore library from l4env. I use > a vanillia revision 230 on an intel PIII architecture. After some > debugging and tracing, I get the following scenarion : > > 1. thread 03 of my process calls a semaphore down timed which then > calls BLOCKTIMED IPC to semaphore thread 02. So semaphore structure is: > counter = -1 > pending = 0 > queue = 03 > > 2. thread 08 calls semaphore_up inline assembler code. Before IPC > call, the semaphore structure is as follow : > counter = 0 > pending = 0 > queue = 03 > > 3. Thread 03 gains the CPU after timeout and calls IPC RELEASETIMED : > counter = 1 > pending = 0 > queue = empty > > 4. Thread 02 doesn't find thread into queue, so that pending is set to 1. > counter = 1 > pending = 1 > queue = empty > > 5. Thread 03 calls semaphore_down. No IPC is called. > counter = 0 > pending = 1 > queue = empty > > 6. Thread 03 calls semaphore_down again and IPC BLOCK is called. IPC > awakes imediately 03 with a counter value of -1 and nobody into queue. > counter = -1 > pending = 0 > queue = empty > > It seems to me that this state is not normal. Do you agree ? Is this > scenario possible as I observe clearly state 4 5 and 6 ? What pending > is for ? Are you just having a problem understanding the observed values or is there a real problem that you are running into? If the latter, could you provide a small example program so that we can reproduce it here? Regards, Bjoern -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iD8DBQFHHbCcP5ijxgQLUNkRAtUAAJ93MKuwxsdhPn5vzWzhRG2ahW+DEgCgiZoo CAy9LWdBVZXb/JJZ5sW+Y1M= =9jpE -----END PGP SIGNATURE----- _______________________________________________ l4-hackers mailing list l4-hackers@os.inf.tu-dresden.de http://os.inf.tu-dresden.de/mailman/listinfo/l4-hackers
