Changeset bc7d44c in mainline for uspace/lib/libc

Timestamp:

2009-08-21T07:33:36Z (16 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

af8e565

Parents:

b9c7425 (diff), 207e208e (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge fibril synchronization improvements.

Location:

uspace/lib/libc

Files:

• generic/async.c (modified) (3 diffs)
• generic/fibril_sync.c (modified) (5 diffs)
• generic/ipc.c (modified) (1 diff)
• include/async.h (modified) (1 diff)
• include/ipc/ipc.h (modified) (1 diff)

uspace/lib/libc/generic/async.c

@@ -106 +106 @@
 
 atomic_t async_futex = FUTEX_INITIALIZER;
+
+/** Number of threads waiting for IPC in the kernel. */
+atomic_t threads_in_ipc_wait = { 0 };
 
 /** Structures of this type represent a waiting fibril. */
@@ -683 +686 @@
                 
                 futex_up(&async_futex);
+
+                atomic_inc(&threads_in_ipc_wait);
                 
                 ipc_call_t call;
@@ -688 +693 @@
                     SYNCH_FLAGS_NONE);
                 
+                atomic_dec(&threads_in_ipc_wait);
+
                 if (!callid) {
                         handle_expired_timeouts();

uspace/lib/libc/generic/fibril_sync.c

@@ -40 +40 @@
 #include <assert.h>
 
+static void optimize_execution_power(void)
+{
+        /*
+         * When waking up a worker fibril previously blocked in fibril
+         * synchronization, chances are that there is an idle manager fibril
+         * waiting for IPC, that could start executing the awakened worker
+         * fibril right away. We try to detect this and bring the manager
+         * fibril back to fruitful work.
+         */
+        if (atomic_get(&threads_in_ipc_wait) > 0)
+                ipc_poke();
+}
+
 void fibril_mutex_initialize(fibril_mutex_t *fm)
 {
@@ -84 +97 @@
                 list_remove(&f->link);
                 fibril_add_ready((fid_t) f);
+                optimize_execution_power();
         }
 }
@@ -152 +166 @@
                         fibril_add_ready((fid_t) f);
                         frw->writers++;
+                        optimize_execution_power();
                         break;
                 } else {
@@ -157 +172 @@
                         fibril_add_ready((fid_t) f);
                         frw->readers++;
+                        optimize_execution_power();
                 }
         }
@@ -200 +216 @@
                 list_remove(&f->link);
                 fibril_add_ready((fid_t) f);
+                optimize_execution_power();
                 if (once)
                         break;

uspace/lib/libc/generic/ipc.c

@@ -565 +565 @@
 }
 
+/** Interrupt one thread of this task from waiting for IPC. */
+void ipc_poke(void)
+{
+        __SYSCALL0(SYS_IPC_POKE);
+}
+
 /** Ask destination to do a callback connection.
  *

uspace/lib/libc/include/async.h

@@ -47 +47 @@
 extern atomic_t async_futex;
 
+extern atomic_t threads_in_ipc_wait;
+
 extern int __async_init(void);
 extern ipc_callid_t async_get_call_timeout(ipc_call_t *call, suseconds_t usecs);

uspace/lib/libc/include/ipc/ipc.h

@@ -192 +192 @@
 extern ipc_callid_t ipc_wait_cycle(ipc_call_t *, uint32_t, int);
 extern ipc_callid_t ipc_wait_for_call_timeout(ipc_call_t *, uint32_t);
+extern void ipc_poke(void);
 
 static inline ipc_callid_t ipc_wait_for_call(ipc_call_t *data)