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replace mutex with condition variable in threadpool

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use TRACE instead of ECHO
(based on cehteh's suggested code)
This commit is contained in:
Michael Ploujnikov 2010-01-04 17:03:47 -05:00
parent 7a507a0cee
commit 223e79cc4a
2 changed files with 58 additions and 46 deletions
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99
src/backend/threadpool.c
View file

@ -45,6 +45,9 @@ NOBUG_DEFINE_FLAG_PARENT (threadpool, threads_dbg); /*TODO insert a suitable/bet
void
lumiera_threadpool_init(void)
{
NOBUG_INIT_FLAG (threadpool);
TRACE (threadpool);
for (int i = 0; i < LUMIERA_THREADCLASS_COUNT; ++i)
{
llist_init (&threadpool.pool[i].list);
@ -55,24 +58,28 @@ lumiera_threadpool_init(void)
pthread_attr_init (&threadpool.pool[i].pthread_attrs);
//cancel...
lumiera_mutex_init (&threadpool.pool[i].lock,"pool of threads", &NOBUG_FLAG (threadpool));
lumiera_condition_init (&threadpool.pool[i].sync,"pool of threads", &NOBUG_FLAG (threadpool));
}
}
void
lumiera_threadpool_destroy(void)
{
ECHO ("destroying threadpool");
TRACE (threadpool);
for (int i = 0; i < LUMIERA_THREADCLASS_COUNT; ++i)
{
ECHO ("destroying individual pool #%d", i);
// no locking is done at this point
ECHO ("number of threads in the pool=%d", llist_count (&threadpool.pool[i].list));
LLIST_WHILE_HEAD (&threadpool.pool[i].list, thread)
lumiera_thread_delete ((LumieraThread)thread);
ECHO ("destroying the pool mutex");
lumiera_mutex_destroy (&threadpool.pool[i].lock, &NOBUG_FLAG (threadpool));
ECHO ("pool mutex destroyed");
TRACE (threadpool, "destroying individual pool #%d", i);
LUMIERA_CONDITION_SECTION (threadpool, &threadpool.pool[i].sync)
{
REQUIRE (0 == threadpool.pool[i].working_thread_count, "%d threads are still running", threadpool.pool[i].working_thread_count);
// TODO need to have a stronger assertion that no threads are really running because they will not even be in the list
INFO (threadpool, "number of threads in the pool=%d", llist_count(&threadpool.pool[i].list));
LLIST_WHILE_HEAD (&threadpool.pool[i].list, t)
{
lumiera_thread_delete ((LumieraThread)t);
}
}
lumiera_condition_destroy (&threadpool.pool[i].sync, &NOBUG_FLAG (threadpool));
pthread_attr_destroy (&threadpool.pool[i].pthread_attrs);
}
}
@ -82,55 +89,61 @@ lumiera_threadpool_acquire_thread(enum lumiera_thread_class kind,
const char* purpose,
struct nobug_flag* flag)
{
LumieraThread ret;
TRACE (threadpool);
LumieraThread ret = NULL;
REQUIRE (kind < LUMIERA_THREADCLASS_COUNT, "unknown pool kind specified: %d", kind);
if (llist_is_empty (&threadpool.pool[kind].list))
LUMIERA_CONDITION_SECTION (threadpool, &threadpool.pool[kind].sync)
{
// TODO: fill in the reccondition argument, currently NULL
ret = lumiera_thread_new (kind, NULL, purpose, flag,
&threadpool.pool[kind].pthread_attrs);
if (llist_is_empty (&threadpool.pool[kind].list))
{
ret = lumiera_thread_new (kind, purpose, flag,
&threadpool.pool[kind].pthread_attrs);
ENSURE (ret, "did not create a valid thread");
TODO ("no error handing, let the resourcecollector do it, no need when returning the thread");
LUMIERA_CONDITION_WAIT (!llist_is_empty (&threadpool.pool[kind].list));
}
// use an existing thread, pick the first one
// remove it from the pool's list
ret = (LumieraThread)(llist_unlink (llist_head (&threadpool.pool[kind].list)));
REQUIRE (ret->state == LUMIERA_THREADSTATE_IDLE, "trying to return a non-idle thread (state=%s)", lumiera_threadstate_names[ret->state]);
threadpool.pool[kind].working_thread_count++;
ENSURE (ret, "did not create a valid thread");
threadpool.pool[kind].idle_thread_count--; // cheaper than using llist_count
ENSURE (threadpool.pool[kind].idle_thread_count ==
llist_count (&threadpool.pool[kind].list),
"idle thread count %d is wrong, should be %d",
threadpool.pool[kind].idle_thread_count,
llist_count (&threadpool.pool[kind].list));
ENSURE (ret, "did not find a valid thread");
}
else
{
// use an existing thread, pick the first one
// remove it from the pool's list
LUMIERA_MUTEX_SECTION (threadpool, &threadpool.pool[kind].lock)
{
ret = (LumieraThread)(llist_unlink (llist_head (&threadpool.pool[kind].list)));
threadpool.pool[kind].working_thread_count++;
threadpool.pool[kind].idle_thread_count--; // cheaper than using llist_count
ENSURE (threadpool.pool[kind].idle_thread_count ==
llist_count (&threadpool.pool[kind].list),
"idle thread count %d is wrong, should be %d",
threadpool.pool[kind].idle_thread_count,
llist_count (&threadpool.pool[kind].list));
}
ENSURE (ret, "did not find a valid thread");
}
return ret;
}
void
lumiera_threadpool_release_thread(LumieraThread thread)
{
TRACE (threadpool);
REQUIRE (thread, "invalid thread given");
REQUIRE (thread->kind < LUMIERA_THREADCLASS_COUNT, "thread belongs to an unknown pool kind: %d", thread->kind);
LUMIERA_MUTEX_SECTION (threadpool, &threadpool.pool[thread->kind].lock)
REQUIRE (thread->state != LUMIERA_THREADSTATE_IDLE, "trying to park an already idle thread");
LUMIERA_CONDITION_SECTION (threadpool, &threadpool.pool[thread->kind].sync)
{
REQUIRE (llist_is_single (&thread->node), "thread already belongs to some list");
thread->state = LUMIERA_THREADSTATE_IDLE;
REQUIRE (llist_is_empty (&thread->node), "thread already belongs to some list");
llist_insert_head (&threadpool.pool[thread->kind].list, &thread->node);
threadpool.pool[thread->kind].working_thread_count--;
threadpool.pool[thread->kind].idle_thread_count++; // cheaper than using llist_count
ENSURE (threadpool.pool[thread->kind].idle_thread_count ==
llist_count (&threadpool.pool[thread->kind].list),
"idle thread count %d is wrong, should be %d",
threadpool.pool[thread->kind].idle_thread_count,
llist_count (&threadpool.pool[thread->kind].list));
// REQUIRE (!llist_is_empty (&threadpool.pool[thread->kind].list), "thread pool is still empty after insertion");
threadpool.pool[thread->kind].working_thread_count--;
threadpool.pool[thread->kind].idle_thread_count++; // cheaper than using llist_count
ENSURE (threadpool.pool[thread->kind].idle_thread_count ==
llist_count (&threadpool.pool[thread->kind].list),
"idle thread count %d is wrong, should be %d",
threadpool.pool[thread->kind].idle_thread_count,
llist_count (&threadpool.pool[thread->kind].list));
REQUIRE (!llist_is_empty (&threadpool.pool[thread->kind].list), "thread pool is still empty after insertion");
LUMIERA_CONDITION_BROADCAST;
}
}

5
src/backend/threadpool.h
View file

@ -23,9 +23,8 @@
#define LUMIERA_THREADPOOL_H
//TODO: Support library includes//
#include "lib/reccondition.h"
#include "lib/condition.h"
#include "lib/llist.h"
#include "lib/mutex.h"
//TODO: Forward declarations//
@ -70,7 +69,7 @@ struct lumiera_threadpool_struct
struct
{
llist list;
lumiera_mutex lock;
lumiera_condition sync;
unsigned working_thread_count;
unsigned idle_thread_count;
pthread_attr_t pthread_attrs;