X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=rts%2Fsm%2FGC.h;h=92e87d1bee9f552f8a3dee5d0a33b521c05d396e;hp=62a4872f2b51d120a33e6ce5bb8870616a19cdcc;hb=f86e7206ea94b48b94fb61007a1c5d55b8c60f45;hpb=ae267d04df855051b99218e3712b3f56b8016d56 diff --git a/rts/sm/GC.h b/rts/sm/GC.h index 62a4872..92e87d1 100644 --- a/rts/sm/GC.h +++ b/rts/sm/GC.h @@ -14,172 +14,8 @@ #ifndef GC_H #define GC_H -#include "OSThreads.h" - -/* ----------------------------------------------------------------------------- - General scheme - - ToDo: move this to the wiki when the implementation is done. - - We're only going to try to parallelise the copying GC for now. The - Plan is as follows. - - Each thread has a gc_thread structure (see below) which holds its - thread-local data. We'll keep a pointer to this in a thread-local - variable, or possibly in a register. - - In the gc_thread structure is a step_workspace for each step. The - primary purpose of the step_workspace is to hold evacuated objects; - when an object is evacuated, it is copied to the "todo" block in - the thread's workspace for the appropriate step. When the todo - block is full, it is pushed to the global step->todos list, which - is protected by a lock. (in fact we intervene a one-place buffer - here to reduce contention). - - A thread repeatedly grabs a block of work from one of the - step->todos lists, scavenges it, and keeps the scavenged block on - its own ws->scavd_list (this is to avoid unnecessary contention - returning the completed buffers back to the step: we can just - collect them all later). - - When there is no global work to do, we start scavenging the todo - blocks in the workspaces. This is where the scan_bd field comes - in: we can scan the contents of the todo block, when we have - scavenged the contents of the todo block (up to todo_bd->free), we - don't want to move this block immediately to the scavd_list, - because it is probably only partially full. So we remember that we - have scanned up to this point by saving the block in ws->scan_bd, - with the current scan pointer in ws->scan. Later, when more - objects have been copied to this block, we can come back and scan - the rest. When we visit this workspace again in the future, - scan_bd may still be the same as todo_bd, or it might be different: - if enough objects were copied into this block that it filled up, - then we will have allocated a new todo block, but *not* pushed the - old one to the step, because it is partially scanned. - - The reason to leave scanning the todo blocks until last is that we - want to deal with full blocks as far as possible. - ------------------------------------------------------------------------- */ - - -/* ----------------------------------------------------------------------------- - Step Workspace - - A step workspace exists for each step for each GC thread. The GC - thread takes a block from the todos list of the step into the - scanbd and then scans it. Objects referred to by those in the scan - block are copied into the todo or scavd blocks of the relevant step. - - ------------------------------------------------------------------------- */ - -typedef struct step_workspace_ { - step * step; // the step for this workspace - struct gc_thread_ * gct; // the gc_thread that contains this workspace - - // where objects to be scavenged go - bdescr * todo_bd; - StgPtr todo_free; // free ptr for todo_bd - StgPtr todo_lim; // lim for todo_bd - - bdescr * buffer_todo_bd; // buffer to reduce contention - // on the step's todos list - - // where large objects to be scavenged go - bdescr * todo_large_objects; - - // Objects that have already been, scavenged. - bdescr * scavd_list; - nat n_scavd_blocks; // count of blocks in this list - - // Partially-full, scavenged, blocks - bdescr * part_list; - unsigned int n_part_blocks; // count of above - -} step_workspace; - -/* ---------------------------------------------------------------------------- - GC thread object - - Every GC thread has one of these. It contains all the step specific - workspaces and other GC thread loacl information. At some later - point it maybe useful to move this other into the TLS store of the - GC threads - ------------------------------------------------------------------------- */ - -typedef struct gc_thread_ { -#ifdef THREADED_RTS - OSThreadId id; // The OS thread that this struct belongs to - Mutex wake_mutex; - Condition wake_cond; // So we can go to sleep between GCs - rtsBool wakeup; - rtsBool exit; -#endif - nat thread_index; // a zero based index identifying the thread - - bdescr * free_blocks; // a buffer of free blocks for this thread - // during GC without accessing the block - // allocators spin lock. - - StgClosure* static_objects; // live static objects - StgClosure* scavenged_static_objects; // static objects scavenged so far - - lnat gc_count; // number of GCs this thread has done - - // block that is currently being scanned - bdescr * scan_bd; - - // -------------------- - // evacuate flags - - step *evac_step; // Youngest generation that objects - // should be evacuated to in - // evacuate(). (Logically an - // argument to evacuate, but it's - // static a lot of the time so we - // optimise it into a per-thread - // variable). - - rtsBool failed_to_evac; // failure to evacuate an object typically - // Causes it to be recorded in the mutable - // object list - - rtsBool eager_promotion; // forces promotion to the evac gen - // instead of the to-space - // corresponding to the object - - lnat thunk_selector_depth; // ummm.... not used as of now - -#ifdef USE_PAPI - int papi_events; -#endif - - // ------------------- - // stats - - lnat copied; - lnat scanned; - lnat any_work; - lnat no_work; - lnat scav_find_work; - - // ------------------- - // workspaces - - // array of workspaces, indexed by stp->abs_no. This is placed - // directly at the end of the gc_thread structure so that we can get from - // the gc_thread pointer to a workspace using only pointer - // arithmetic, no memory access. This happens in the inner loop - // of the GC, see Evac.c:alloc_for_copy(). - step_workspace steps[]; -} gc_thread; - extern nat N; extern rtsBool major_gc; -extern nat n_gc_threads; - -extern gc_thread **gc_threads; -register gc_thread *gct __asm__("%rbx"); -// extern gc_thread *gct; // this thread's gct TODO: make thread-local extern bdescr *mark_stack_bdescr; extern StgPtr *mark_stack; @@ -196,7 +32,15 @@ extern long copied; extern nat mutlist_MUTVARS, mutlist_MUTARRS, mutlist_MVARS, mutlist_OTHERS; #endif -StgClosure * isAlive(StgClosure *p); +extern void markSomeCapabilities (evac_fn evac, void *user, nat i0, nat delta); + +#ifdef THREADED_RTS +extern SpinLock gc_alloc_block_sync; +#endif + +#if defined(PROF_SPIN) && defined(THREADED_RTS) +StgWord64 whitehole_spin; +#endif #define WORK_UNIT_WORDS 128