X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=rts%2FCapability.c;h=ddaba699a36615da472423187a9134e268a71b15;hp=516aaa573d26e62ee88a628ea51b06904ca4315f;hb=a2a67cd520b9841114d69a87a423dabcb3b4368e;hpb=cf9650f2a1690c04051c716124bb0350adc74ae7 diff --git a/rts/Capability.c b/rts/Capability.c index 516aaa5..ddaba69 100644 --- a/rts/Capability.c +++ b/rts/Capability.c @@ -18,31 +18,46 @@ #include "PosixSource.h" #include "Rts.h" -#include "RtsUtils.h" -#include "RtsFlags.h" -#include "STM.h" -#include "OSThreads.h" + #include "Capability.h" #include "Schedule.h" #include "Sparks.h" #include "Trace.h" +#include "sm/GC.h" // for gcWorkerThread() +#include "STM.h" +#include "RtsUtils.h" // one global capability, this is the Capability for non-threaded // builds, and for +RTS -N1 Capability MainCapability; -nat n_capabilities; +nat n_capabilities = 0; Capability *capabilities = NULL; // Holds the Capability which last became free. This is used so that // an in-call has a chance of quickly finding a free Capability. // Maintaining a global free list of Capabilities would require global // locking, so we don't do that. -Capability *last_free_capability; +Capability *last_free_capability = NULL; /* GC indicator, in scope for the scheduler, init'ed to false */ volatile StgWord waiting_for_gc = 0; +/* Let foreign code get the current Capability -- assuming there is one! + * This is useful for unsafe foreign calls because they are called with + * the current Capability held, but they are not passed it. For example, + * see see the integer-gmp package which calls allocateLocal() in its + * stgAllocForGMP() function (which gets called by gmp functions). + * */ +Capability * rts_unsafeGetMyCapability (void) +{ +#if defined(THREADED_RTS) + return myTask()->cap; +#else + return &MainCapability; +#endif +} + #if defined(THREADED_RTS) STATIC_INLINE rtsBool globalWorkToDo (void) @@ -54,80 +69,98 @@ globalWorkToDo (void) #endif #if defined(THREADED_RTS) -rtsBool stealWork( Capability *cap) { - /* use the normal Sparks.h interface (internally modified to enable - concurrent stealing) - and immediately turn the spark into a thread when successful - */ +StgClosure * +findSpark (Capability *cap) +{ Capability *robbed; - SparkPool *pool; StgClosurePtr spark; - rtsBool success = rtsFalse; + rtsBool retry; nat i = 0; + if (!emptyRunQueue(cap)) { + // If there are other threads, don't try to run any new + // sparks: sparks might be speculative, we don't want to take + // resources away from the main computation. + return 0; + } + + // first try to get a spark from our own pool. + // We should be using reclaimSpark(), because it works without + // needing any atomic instructions: + // spark = reclaimSpark(cap->sparks); + // However, measurements show that this makes at least one benchmark + // slower (prsa) and doesn't affect the others. + spark = tryStealSpark(cap); + if (spark != NULL) { + cap->sparks_converted++; + + // Post event for running a spark from capability's own pool. + postEvent(cap, EVENT_RUN_SPARK, cap->r.rCurrentTSO->id, 0); + + return spark; + } + + if (n_capabilities == 1) { return NULL; } // makes no sense... + debugTrace(DEBUG_sched, "cap %d: Trying to steal work from other capabilities", cap->no); - if (n_capabilities == 1) { return rtsFalse; } // makes no sense... + do { + retry = rtsFalse; - /* visit cap.s 0..n-1 in sequence until a theft succeeds. We could - start at a random place instead of 0 as well. */ - for ( i=0 ; i < n_capabilities ; i++ ) { - robbed = &capabilities[i]; - if (cap == robbed) // ourselves... - continue; + /* visit cap.s 0..n-1 in sequence until a theft succeeds. We could + start at a random place instead of 0 as well. */ + for ( i=0 ; i < n_capabilities ; i++ ) { + robbed = &capabilities[i]; + if (cap == robbed) // ourselves... + continue; - if (emptySparkPoolCap(robbed)) // nothing to steal here - continue; - - spark = findSpark(robbed); + if (emptySparkPoolCap(robbed)) // nothing to steal here + continue; - if (spark == NULL && !emptySparkPoolCap(robbed)) { - spark = findSpark(robbed); // lost race in concurrent access, try again - } - if (spark != NULL) { - debugTrace(DEBUG_sched, - "cap %d: Stole a spark from capability %d", - cap->no, robbed->no); + spark = tryStealSpark(robbed); + if (spark == NULL && !emptySparkPoolCap(robbed)) { + // we conflicted with another thread while trying to steal; + // try again later. + retry = rtsTrue; + } - createSparkThread(cap,spark); - success = rtsTrue; - break; // got one, leave the loop - } - // otherwise: no success, try next one - } - debugTrace(DEBUG_sched, - "Leaving work stealing routine (%s)", - success?"one spark stolen":"thefts did not succeed"); - return success; + if (spark != NULL) { + debugTrace(DEBUG_sched, + "cap %d: Stole a spark from capability %d", + cap->no, robbed->no); + cap->sparks_converted++; + + postEvent(cap, EVENT_STEAL_SPARK, + cap->r.rCurrentTSO->id, robbed->no); + + + return spark; + } + // otherwise: no success, try next one + } + } while (retry); + + debugTrace(DEBUG_sched, "No sparks stolen"); + return NULL; } -STATIC_INLINE rtsBool -anyWorkForMe( Capability *cap, Task *task ) +// Returns True if any spark pool is non-empty at this moment in time +// The result is only valid for an instant, of course, so in a sense +// is immediately invalid, and should not be relied upon for +// correctness. +rtsBool +anySparks (void) { - if (task->tso != NULL) { - // A bound task only runs if its thread is on the run queue of - // the capability on which it was woken up. Otherwise, we - // can't be sure that we have the right capability: the thread - // might be woken up on some other capability, and task->cap - // could change under our feet. - return !emptyRunQueue(cap) && cap->run_queue_hd->bound == task; - } else { - // A vanilla worker task runs if either there is a lightweight - // thread at the head of the run queue, or the run queue is - // empty and (there are sparks to execute, or there is some - // other global condition to check, such as threads blocked on - // blackholes). - if (emptyRunQueue(cap)) { - return !emptySparkPoolCap(cap) - || !emptyWakeupQueue(cap) - || globalWorkToDo() - || stealWork(cap); /* if all false: try to steal work */ - } else { - return cap->run_queue_hd->bound == NULL; - } + nat i; + + for (i=0; i < n_capabilities; i++) { + if (!emptySparkPoolCap(&capabilities[i])) { + return rtsTrue; + } } + return rtsFalse; } #endif @@ -181,6 +214,7 @@ initCapability( Capability *cap, nat i ) cap->no = i; cap->in_haskell = rtsFalse; + cap->in_gc = rtsFalse; cap->run_queue_hd = END_TSO_QUEUE; cap->run_queue_tl = END_TSO_QUEUE; @@ -194,14 +228,21 @@ initCapability( Capability *cap, nat i ) cap->returning_tasks_tl = NULL; cap->wakeup_queue_hd = END_TSO_QUEUE; cap->wakeup_queue_tl = END_TSO_QUEUE; + cap->sparks_created = 0; + cap->sparks_converted = 0; + cap->sparks_pruned = 0; #endif - cap->f.stgGCEnter1 = (F_)__stg_gc_enter_1; - cap->f.stgGCFun = (F_)__stg_gc_fun; + cap->f.stgEagerBlackholeInfo = (W_)&__stg_EAGER_BLACKHOLE_info; + cap->f.stgGCEnter1 = (StgFunPtr)__stg_gc_enter_1; + cap->f.stgGCFun = (StgFunPtr)__stg_gc_fun; cap->mut_lists = stgMallocBytes(sizeof(bdescr *) * RtsFlags.GcFlags.generations, "initCapability"); + cap->saved_mut_lists = stgMallocBytes(sizeof(bdescr *) * + RtsFlags.GcFlags.generations, + "initCapability"); for (g = 0; g < RtsFlags.GcFlags.generations; g++) { cap->mut_lists[g] = NULL; @@ -276,10 +317,10 @@ initCapabilities( void ) void setContextSwitches(void) { - nat i; - for (i=0; i < n_capabilities; i++) { - capabilities[i].context_switch = 1; - } + nat i; + for (i=0; i < n_capabilities; i++) { + contextSwitchCapability(&capabilities[i]); + } } /* ---------------------------------------------------------------------------- @@ -302,10 +343,9 @@ giveCapabilityToTask (Capability *cap USED_IF_DEBUG, Task *task) { ASSERT_LOCK_HELD(&cap->lock); ASSERT(task->cap == cap); - trace(TRACE_sched | DEBUG_sched, - "passing capability %d to %s %p", - cap->no, task->tso ? "bound task" : "worker", - (void *)task->id); + debugTrace(DEBUG_sched, "passing capability %d to %s %p", + cap->no, task->tso ? "bound task" : "worker", + (void *)task->id); ACQUIRE_LOCK(&task->lock); task->wakeup = rtsTrue; // the wakeup flag is needed because signalCondition() doesn't @@ -326,7 +366,8 @@ giveCapabilityToTask (Capability *cap USED_IF_DEBUG, Task *task) #if defined(THREADED_RTS) void -releaseCapability_ (Capability* cap) +releaseCapability_ (Capability* cap, + rtsBool always_wakeup) { Task *task; @@ -344,17 +385,9 @@ releaseCapability_ (Capability* cap) return; } - /* if waiting_for_gc was the reason to release the cap: thread - comes from yieldCap->releaseAndQueueWorker. Unconditionally set - cap. free and return (see default after the if-protected other - special cases). Thread will wait on cond.var and re-acquire the - same cap after GC (GC-triggering cap. calls releaseCap and - enters the spare_workers case) - */ - if (waiting_for_gc) { + if (waiting_for_gc == PENDING_GC_SEQ) { last_free_capability = cap; // needed? - trace(TRACE_sched | DEBUG_sched, - "GC pending, set capability %d free", cap->no); + debugTrace(DEBUG_sched, "GC pending, set capability %d free", cap->no); return; } @@ -384,8 +417,9 @@ releaseCapability_ (Capability* cap) // If we have an unbound thread on the run queue, or if there's // anything else to do, give the Capability to a worker thread. - if (!emptyRunQueue(cap) || !emptyWakeupQueue(cap) - || !emptySparkPoolCap(cap) || globalWorkToDo()) { + if (always_wakeup || + !emptyRunQueue(cap) || !emptyWakeupQueue(cap) || + !emptySparkPoolCap(cap) || globalWorkToDo()) { if (cap->spare_workers) { giveCapabilityToTask(cap,cap->spare_workers); // The worker Task pops itself from the queue; @@ -394,14 +428,22 @@ releaseCapability_ (Capability* cap) } last_free_capability = cap; - trace(TRACE_sched | DEBUG_sched, "freeing capability %d", cap->no); + debugTrace(DEBUG_sched, "freeing capability %d", cap->no); } void releaseCapability (Capability* cap USED_IF_THREADS) { ACQUIRE_LOCK(&cap->lock); - releaseCapability_(cap); + releaseCapability_(cap, rtsFalse); + RELEASE_LOCK(&cap->lock); +} + +void +releaseAndWakeupCapability (Capability* cap USED_IF_THREADS) +{ + ACQUIRE_LOCK(&cap->lock); + releaseCapability_(cap, rtsTrue); RELEASE_LOCK(&cap->lock); } @@ -427,7 +469,7 @@ releaseCapabilityAndQueueWorker (Capability* cap USED_IF_THREADS) } // Bound tasks just float around attached to their TSOs. - releaseCapability_(cap); + releaseCapability_(cap,rtsFalse); RELEASE_LOCK(&cap->lock); } @@ -461,14 +503,17 @@ waitForReturnCapability (Capability **pCap, Task *task) if (!cap->running_task) { nat i; // otherwise, search for a free capability + cap = NULL; for (i = 0; i < n_capabilities; i++) { - cap = &capabilities[i]; - if (!cap->running_task) { + if (!capabilities[i].running_task) { + cap = &capabilities[i]; break; } } - // Can't find a free one, use last_free_capability. - cap = last_free_capability; + if (cap == NULL) { + // Can't find a free one, use last_free_capability. + cap = last_free_capability; + } } // record the Capability as the one this Task is now assocated with. @@ -518,7 +563,7 @@ waitForReturnCapability (Capability **pCap, Task *task) ASSERT_FULL_CAPABILITY_INVARIANTS(cap,task); - trace(TRACE_sched | DEBUG_sched, "resuming capability %d", cap->no); + debugTrace(DEBUG_sched, "resuming capability %d", cap->no); *pCap = cap; #endif @@ -534,16 +579,14 @@ yieldCapability (Capability** pCap, Task *task) { Capability *cap = *pCap; - // The fast path has no locking, if we don't enter this while loop + if (waiting_for_gc == PENDING_GC_PAR) { + debugTrace(DEBUG_sched, "capability %d: becoming a GC thread", cap->no); + postEvent(cap, EVENT_GC_START, 0, 0); + gcWorkerThread(cap); + postEvent(cap, EVENT_GC_END, 0, 0); + return; + } - while ( waiting_for_gc - /* i.e. another capability triggered HeapOverflow, is busy - getting capabilities (stopping their owning tasks) */ - || cap->returning_tasks_hd != NULL - /* cap reserved for another task */ - || !anyWorkForMe(cap,task) - /* cap/task have no work */ - ) { debugTrace(DEBUG_sched, "giving up capability %d", cap->no); // We must now release the capability and wait to be woken up @@ -586,9 +629,8 @@ yieldCapability (Capability** pCap, Task *task) break; } - trace(TRACE_sched | DEBUG_sched, "resuming capability %d", cap->no); + debugTrace(DEBUG_sched, "resuming capability %d", cap->no); ASSERT(cap->running_task == task); - } *pCap = cap; @@ -629,8 +671,7 @@ wakeupThreadOnCapability (Capability *my_cap, appendToRunQueue(other_cap,tso); - trace(TRACE_sched, "resuming capability %d", other_cap->no); - releaseCapability_(other_cap); + releaseCapability_(other_cap,rtsFalse); } else { appendToWakeupQueue(my_cap,other_cap,tso); other_cap->context_switch = 1; @@ -643,58 +684,21 @@ wakeupThreadOnCapability (Capability *my_cap, } /* ---------------------------------------------------------------------------- - * prodCapabilities + * prodCapability * - * Used to indicate that the interrupted flag is now set, or some - * other global condition that might require waking up a Task on each - * Capability. + * If a Capability is currently idle, wake up a Task on it. Used to + * get every Capability into the GC. * ------------------------------------------------------------------------- */ -static void -prodCapabilities(rtsBool all) -{ - nat i; - Capability *cap; - Task *task; - - for (i=0; i < n_capabilities; i++) { - cap = &capabilities[i]; - ACQUIRE_LOCK(&cap->lock); - if (!cap->running_task) { - if (cap->spare_workers) { - trace(TRACE_sched, "resuming capability %d", cap->no); - task = cap->spare_workers; - ASSERT(!task->stopped); - giveCapabilityToTask(cap,task); - if (!all) { - RELEASE_LOCK(&cap->lock); - return; - } - } - } - RELEASE_LOCK(&cap->lock); - } - return; -} - void -prodAllCapabilities (void) +prodCapability (Capability *cap, Task *task) { - prodCapabilities(rtsTrue); -} - -/* ---------------------------------------------------------------------------- - * prodOneCapability - * - * Like prodAllCapabilities, but we only require a single Task to wake - * up in order to service some global event, such as checking for - * deadlock after some idle time has passed. - * ------------------------------------------------------------------------- */ - -void -prodOneCapability (void) -{ - prodCapabilities(rtsFalse); + ACQUIRE_LOCK(&cap->lock); + if (!cap->running_task) { + cap->running_task = task; + releaseCapability_(cap,rtsTrue); + } + RELEASE_LOCK(&cap->lock); } /* ---------------------------------------------------------------------------- @@ -717,8 +721,6 @@ shutdownCapability (Capability *cap, Task *task, rtsBool safe) { nat i; - ASSERT(sched_state == SCHED_SHUTTING_DOWN); - task->cap = cap; // Loop indefinitely until all the workers have exited and there @@ -728,6 +730,8 @@ shutdownCapability (Capability *cap, Task *task, rtsBool safe) // isn't safe, for one thing). for (i = 0; /* i < 50 */; i++) { + ASSERT(sched_state == SCHED_SHUTTING_DOWN); + debugTrace(DEBUG_sched, "shutting down capability %d, attempt %d", cap->no, i); ACQUIRE_LOCK(&cap->lock); @@ -765,7 +769,7 @@ shutdownCapability (Capability *cap, Task *task, rtsBool safe) if (!emptyRunQueue(cap) || cap->spare_workers) { debugTrace(DEBUG_sched, "runnable threads or workers still alive, yielding"); - releaseCapability_(cap); // this will wake up a worker + releaseCapability_(cap,rtsFalse); // this will wake up a worker RELEASE_LOCK(&cap->lock); yieldThread(); continue; @@ -786,8 +790,8 @@ shutdownCapability (Capability *cap, Task *task, rtsBool safe) continue; } + postEvent(cap, EVENT_SHUTDOWN, 0, 0); debugTrace(DEBUG_sched, "capability %d is stopped.", cap->no); - freeCapability(cap); RELEASE_LOCK(&cap->lock); break; } @@ -825,14 +829,28 @@ tryGrabCapability (Capability *cap, Task *task) #endif /* THREADED_RTS */ -void -freeCapability (Capability *cap) { +static void +freeCapability (Capability *cap) +{ stgFree(cap->mut_lists); -#if defined(THREADED_RTS) || defined(PARALLEL_HASKELL) +#if defined(THREADED_RTS) freeSparkPool(cap->sparks); #endif } +void +freeCapabilities (void) +{ +#if defined(THREADED_RTS) + nat i; + for (i=0; i < n_capabilities; i++) { + freeCapability(&capabilities[i]); + } +#else + freeCapability(&MainCapability); +#endif +} + /* --------------------------------------------------------------------------- Mark everything directly reachable from the Capabilities. When using multiple GC threads, each GC thread marks all Capabilities @@ -840,7 +858,8 @@ freeCapability (Capability *cap) { ------------------------------------------------------------------------ */ void -markSomeCapabilities (evac_fn evac, void *user, nat i0, nat delta) +markSomeCapabilities (evac_fn evac, void *user, nat i0, nat delta, + rtsBool prune_sparks USED_IF_THREADS) { nat i; Capability *cap; @@ -867,7 +886,11 @@ markSomeCapabilities (evac_fn evac, void *user, nat i0, nat delta) } #if defined(THREADED_RTS) - traverseSparkQueue (evac, user, cap); + if (prune_sparks) { + pruneSparkQueue (evac, user, cap); + } else { + traverseSparkQueue (evac, user, cap); + } #endif } @@ -878,22 +901,8 @@ markSomeCapabilities (evac_fn evac, void *user, nat i0, nat delta) #endif } -// This function is used by the compacting GC to thread all the -// pointers from spark queues. -void -traverseSparkQueues (evac_fn evac USED_IF_THREADS, void *user USED_IF_THREADS) -{ -#if defined(THREADED_RTS) - nat i; - for (i = 0; i < n_capabilities; i++) { - traverseSparkQueue (evac, user, &capabilities[i]); - } -#endif // THREADED_RTS - -} - void markCapabilities (evac_fn evac, void *user) { - markSomeCapabilities(evac, user, 0, 1); + markSomeCapabilities(evac, user, 0, 1, rtsFalse); }