:> :--- uthread_create.c 1999/03/23 05:07:55 1.12 :> :+++ uthread_create.c 1999/05/06 15:27:33 :> :@@ -42,6 +42,8 @@ :> : #include "pthread_private.h" :> : #include "libc_private.h" :> : :> :+static int next_tid = 1; :> :+ :> : int :> : pthread_create(pthread_t * thread, const pthread_attr_t * attr, :> : void *(*start_routine) (void *), void *arg) :> :@@ -87,6 +89,7 @@ :> : } else { :> : /* Initialise the thread structure: */ :> : memset(new_thread, 0, sizeof(struct pthread)); :> :+ new_thread->tid = next_tid++; :> : :> :Doug Rabson Mail: d...@nlsystems.com :> :Nonlinear Systems Ltd. Phone: +44 181 442 9037 :> :> Hmmm. tid is only an int and some programs which create and destroy :> threads a lot are almost certainly going to overflow it. 4 billion :> is not hard to reach. This can result in duplicate tid's. : :Didn't think of that. It gets a bit ugly inside gdb since gdb needs a :single int to encode the pid and thread id. I'm currently allowing 20 :bits for the pid and 11 for the tid. Any ideas? : :-- :Doug Rabson Mail: d...@nlsystems.com :Nonlinear Systems Ltd. Phone: +44 181 442 9037
Hmmm. 11 bits is only 2048 threads. You are going to have problems no matter what. You could have a pool of tid structures. A simple freelist. Pseudo code below. This would fix the unique-tid problem but it would not fix the 2048 thread limit with gdb. #define TIDINCR 32 struct tid { struct tid *t_next; int t_tid; }; int maxtid = 1; struct tid *tidpool; struct tid * alloctid(void) { struct tid *tid; while ((tid = tidpool) == NULL) { int i; tidpool = malloc(sizeof(struct tid) * TIDINCR); if (tidpool == NULL) { ... memory allocation failed ... } for (i = 0; i < TIDINCR; ++i) { tidpool[i].t_tid = maxtid + i; tidpool[i].t_next = &tidpool[i+1]; } tidpool[i-1].t_next = NULL; maxtid += TIDINCR; } tidpool = tid->t_next; return(tid); } freetid(struct tid *tid) { tid->t_next = tidpool; tidpool = tid; } -Matt Matthew Dillon <dil...@backplane.com> To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-current" in the body of the message