*
* Capabilities
*
- * The notion of a capability is used when operating in multi-threaded
- * environments (which the THREADED_RTS build of the RTS does), to
- * hold all the state an OS thread/task needs to run Haskell code:
- * its STG registers, a pointer to its TSO, a nursery etc. During
- * STG execution, a pointer to the capabilitity is kept in a
- * register (BaseReg).
+ * For details on the high-level design, see
+ * http://hackage.haskell.org/trac/ghc/wiki/Commentary/Rts/Scheduler
*
- * Only in an THREADED_RTS build will there be multiple capabilities,
- * in the non-threaded builds there is one global capability, namely
+ * A Capability holds all the state an OS thread/task needs to run
+ * Haskell code: its STG registers, a pointer to its TSO, a nursery
+ * etc. During STG execution, a pointer to the Capabilitity is kept in
+ * a register (BaseReg).
+ *
+ * Only in a THREADED_RTS build will there be multiple capabilities,
+ * in the non-threaded RTS there is one global capability, called
* MainCapability.
*
- * This header file contains the functions for working with capabilities.
- * (the main, and only, consumer of this interface is the scheduler).
- *
* --------------------------------------------------------------------------*/
#ifndef CAPABILITY_H
#define CAPABILITY_H
-#include "RtsFlags.h"
+#include "sm/GC.h" // for evac_fn
#include "Task.h"
#include "Sparks.h"
+#include "BeginPrivate.h"
+
struct Capability_ {
// State required by the STG virtual machine when running Haskell
// code. During STG execution, the BaseReg register always points
// the suspended TSOs easily. Hence, when migrating a Task from
// the returning_tasks list, we must also migrate its entry from
// this list.
- Task *suspended_ccalling_tasks;
+ InCall *suspended_ccalls;
// One mutable list per generation, so we don't need to take any
- // locks when updating an old-generation thunk. These
- // mini-mut-lists are moved onto the respective gen->mut_list at
- // each GC.
+ // locks when updating an old-generation thunk. This also lets us
+ // keep track of which closures this CPU has been mutating, so we
+ // can traverse them using the right thread during GC and avoid
+ // unnecessarily moving the data from one cache to another.
bdescr **mut_lists;
+ bdescr **saved_mut_lists; // tmp use during GC
+
+ // block for allocating pinned objects into
+ bdescr *pinned_object_block;
// Context switch flag. We used to have one global flag, now one
// per capability. Locks required : none (conflicts are harmless)
#if defined(THREADED_RTS)
// Worker Tasks waiting in the wings. Singly-linked.
Task *spare_workers;
+ nat n_spare_workers; // count of above
// This lock protects running_task, returning_tasks_{hd,tl}, wakeup_queue.
Mutex lock;
Task *returning_tasks_hd; // Singly-linked, with head/tail
Task *returning_tasks_tl;
- // A list of threads to append to this Capability's run queue at
- // the earliest opportunity. These are threads that have been
- // woken up by another Capability.
- StgTSO *wakeup_queue_hd;
- StgTSO *wakeup_queue_tl;
+ // Messages, or END_TSO_QUEUE.
+ Message *inbox;
SparkPool *sparks;
// Stats on spark creation/conversion
nat sparks_created;
+ nat sparks_dud;
nat sparks_converted;
- nat sparks_pruned;
+ nat sparks_gcd;
+ nat sparks_fizzled;
#endif
// Per-capability STM-related data
} // typedef Capability is defined in RtsAPI.h
// Capabilities are stored in an array, so make sure that adjacent
// Capabilities don't share any cache-lines:
- ATTRIBUTE_ALIGNED(64);
+#ifndef mingw32_HOST_OS
+ ATTRIBUTE_ALIGNED(64)
+#endif
+ ;
#if defined(THREADED_RTS)
INLINE_HEADER Capability *
regTableToCapability (StgRegTable *reg)
{
- return (Capability *)((void *)((unsigned char*)reg - sizeof(StgFunTable)));
+ return (Capability *)((void *)((unsigned char*)reg - STG_FIELD_OFFSET(Capability,r)));
}
// Initialise the available capabilities.
rtsBool always_wakeup STG_UNUSED) {};
#endif
-#if !IN_STG_CODE
-// one global capability
-extern Capability MainCapability;
-#endif
+// declared in includes/rts/Threads.h:
+// extern Capability MainCapability;
+
+// declared in includes/rts/Threads.h:
+// extern nat n_capabilities;
// Array of all the capabilities
//
-extern nat n_capabilities;
extern Capability *capabilities;
// The Capability that was last free. Used as a good guess for where
extern Capability *last_free_capability;
// GC indicator, in scope for the scheduler
+#define PENDING_GC_SEQ 1
+#define PENDING_GC_PAR 2
extern volatile StgWord waiting_for_gc;
// Acquires a capability at a return point. If *cap is non-NULL, then
//
void waitForReturnCapability (Capability **cap/*in/out*/, Task *task);
-INLINE_HEADER void recordMutableCap (StgClosure *p, Capability *cap, nat gen);
+EXTERN_INLINE void recordMutableCap (StgClosure *p, Capability *cap, nat gen);
+
+EXTERN_INLINE void recordClosureMutated (Capability *cap, StgClosure *p);
#if defined(THREADED_RTS)
//
void waitForCapability (Task *task, Mutex *mutex, Capability **pCap);
-// Wakes up a thread on a Capability (probably a different Capability
-// from the one held by the current Task).
-//
-void wakeupThreadOnCapability (Capability *my_cap, Capability *other_cap,
- StgTSO *tso);
-
// Wakes up a worker thread on just one Capability, used when we
// need to service some global event.
//
void prodOneCapability (void);
+void prodCapability (Capability *cap, Task *task);
// Similar to prodOneCapability(), but prods all of them.
//
void prodAllCapabilities (void);
-// Waits for a capability to drain of runnable threads and workers,
-// and then acquires it. Used at shutdown time.
-//
-void shutdownCapability (Capability *cap, Task *task, rtsBool wait_foreign);
-
// Attempt to gain control of a Capability if it is free.
//
rtsBool tryGrabCapability (Capability *cap, Task *task);
-// Try to steal a spark from other Capabilities
+// Try to find a spark to run
+//
+StgClosure *findSpark (Capability *cap);
+
+// True if any capabilities have sparks
//
-rtsBool stealWork (Capability *cap);
+rtsBool anySparks (void);
INLINE_HEADER rtsBool emptySparkPoolCap (Capability *cap);
INLINE_HEADER nat sparkPoolSizeCap (Capability *cap);
#endif /* !THREADED_RTS */
+// Waits for a capability to drain of runnable threads and workers,
+// and then acquires it. Used at shutdown time.
+//
+void shutdownCapability (Capability *cap, Task *task, rtsBool wait_foreign);
+
+// Shut down all capabilities.
+//
+void shutdownCapabilities(Task *task, rtsBool wait_foreign);
+
// cause all capabilities to context switch as soon as possible.
void setContextSwitches(void);
+INLINE_HEADER void contextSwitchCapability(Capability *cap);
+
+// Free all capabilities
+void freeCapabilities (void);
-// Free a capability on exit
-void freeCapability (Capability *cap);
+// For the GC:
+void markCapability (evac_fn evac, void *user, Capability *cap,
+ rtsBool no_mark_sparks USED_IF_THREADS);
-// FOr the GC:
-void markSomeCapabilities (evac_fn evac, void *user, nat i0, nat delta,
- rtsBool prune_sparks);
void markCapabilities (evac_fn evac, void *user);
+
void traverseSparkQueues (evac_fn evac, void *user);
/* -----------------------------------------------------------------------------
+ Messages
+ -------------------------------------------------------------------------- */
+
+#ifdef THREADED_RTS
+
+INLINE_HEADER rtsBool emptyInbox(Capability *cap);;
+
+#endif // THREADED_RTS
+
+/* -----------------------------------------------------------------------------
* INLINE functions... private below here
* -------------------------------------------------------------------------- */
-INLINE_HEADER void
+EXTERN_INLINE void
recordMutableCap (StgClosure *p, Capability *cap, nat gen)
{
bdescr *bd;
// We must own this Capability in order to modify its mutable list.
- ASSERT(cap->running_task == myTask());
+ // ASSERT(cap->running_task == myTask());
+ // NO: assertion is violated by performPendingThrowTos()
bd = cap->mut_lists[gen];
if (bd->free >= bd->start + BLOCK_SIZE_W) {
bdescr *new_bd;
*bd->free++ = (StgWord)p;
}
+EXTERN_INLINE void
+recordClosureMutated (Capability *cap, StgClosure *p)
+{
+ bdescr *bd;
+ bd = Bdescr((StgPtr)p);
+ if (bd->gen_no != 0) recordMutableCap(p,cap,bd->gen_no);
+}
+
+
#if defined(THREADED_RTS)
INLINE_HEADER rtsBool
emptySparkPoolCap (Capability *cap)
{ return discardSparks(cap->sparks); }
#endif
+INLINE_HEADER void
+contextSwitchCapability (Capability *cap)
+{
+ // setting HpLim to NULL ensures that the next heap check will
+ // fail, and the thread will return to the scheduler.
+ cap->r.rHpLim = NULL;
+ // But just in case it didn't work (the target thread might be
+ // modifying HpLim at the same time), we set the end-of-block
+ // context-switch flag too:
+ cap->context_switch = 1;
+}
+
+#ifdef THREADED_RTS
+
+INLINE_HEADER rtsBool emptyInbox(Capability *cap)
+{
+ return (cap->inbox == (Message*)END_TSO_QUEUE);
+}
+
+#endif
+
+#include "EndPrivate.h"
+
#endif /* CAPABILITY_H */
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