*
* ---------------------------------------------------------------------------*/
-#include "PosixSource.h"
+// #include "PosixSource.h"
#include "Rts.h"
#include "RtsFlags.h"
#include "RtsUtils.h"
#include "Sparks.h"
#include <string.h> // for memset()
+#include <unistd.h>
/* -----------------------------------------------------------------------------
Global variables
static void mark_root (StgClosure **root);
static void zero_static_object_list (StgClosure* first_static);
-static void initialise_N (rtsBool force_major_gc);
+static nat initialise_N (rtsBool force_major_gc);
static void alloc_gc_threads (void);
static void init_collected_gen (nat g, nat threads);
static void init_uncollected_gen (nat g, nat threads);
static nat inc_running (void);
static nat dec_running (void);
static void wakeup_gc_threads (nat n_threads);
+static void shutdown_gc_threads (nat n_threads);
#if 0 && defined(DEBUG)
static void gcCAFs (void);
{
bdescr *bd;
step *stp;
- lnat live, allocated;
+ lnat live, allocated, max_copied, avg_copied, slop;
lnat oldgen_saved_blocks = 0;
gc_thread *saved_gct;
- nat g, s, t;
+ nat g, s, t, n;
// necessary if we stole a callee-saves register for gct:
saved_gct = gct;
ACQUIRE_SM_LOCK;
- debugTrace(DEBUG_gc, "starting GC");
-
#if defined(RTS_USER_SIGNALS)
if (RtsFlags.MiscFlags.install_signal_handlers) {
// block signals
/* Figure out which generation to collect
*/
- initialise_N(force_major_gc);
+ n = initialise_N(force_major_gc);
/* Allocate + initialise the gc_thread structures.
*/
* We don't try to parallelise minor GC.
*/
#if defined(THREADED_RTS)
- if (N == 0) {
+ if (n < (4*1024*1024 / BLOCK_SIZE)) {
n_gc_threads = 1;
} else {
n_gc_threads = RtsFlags.ParFlags.gcThreads;
#else
n_gc_threads = 1;
#endif
+ trace(TRACE_gc|DEBUG_gc, "GC (gen %d): %dKB to collect, using %d thread(s)",
+ N, n * (BLOCK_SIZE / 1024), n_gc_threads);
#ifdef RTS_GTK_FRONTPANEL
if (RtsFlags.GcFlags.frontpanel) {
// check stack sanity *before* GC (ToDo: check all threads)
IF_DEBUG(sanity, checkFreeListSanity());
+ // Initialise all our gc_thread structures
+ for (t = 0; t < n_gc_threads; t++) {
+ init_gc_thread(gc_threads[t]);
+ }
+
// Initialise all the generations/steps that we're collecting.
for (g = 0; g <= N; g++) {
init_collected_gen(g,n_gc_threads);
mark_stack_bdescr = NULL;
}
- // Initialise all our gc_thread structures
- for (t = 0; t < n_gc_threads; t++) {
- init_gc_thread(gc_threads[t]);
- }
-
- // the main thread is running: this prevents any other threads from
- // exiting prematurely, so we can start them now.
- inc_running();
- wakeup_gc_threads(n_gc_threads);
-
// this is the main thread
gct = gc_threads[0];
* Also do them in reverse generation order, for the usual reason:
* namely to reduce the likelihood of spurious old->new pointers.
*/
- {
- for (g = RtsFlags.GcFlags.generations-1; g > N; g--) {
+ for (g = RtsFlags.GcFlags.generations-1; g > N; g--) {
generations[g].saved_mut_list = generations[g].mut_list;
generations[g].mut_list = allocBlock();
- // mut_list always has at least one block.
- }
- for (g = RtsFlags.GcFlags.generations-1; g > N; g--) {
+ // mut_list always has at least one block.
+ }
+
+ // the main thread is running: this prevents any other threads from
+ // exiting prematurely, so we can start them now.
+ // NB. do this after the mutable lists have been saved above, otherwise
+ // the other GC threads will be writing into the old mutable lists.
+ inc_running();
+ wakeup_gc_threads(n_gc_threads);
+
+ for (g = RtsFlags.GcFlags.generations-1; g > N; g--) {
scavenge_mutable_list(&generations[g]);
- }
}
// follow roots from the CAF list (used by GHCi)
break;
}
+ shutdown_gc_threads(n_gc_threads);
+
// Update pointers from the Task list
update_task_list();
{
gc_thread *thr;
step_workspace *ws;
- bdescr *prev;
+ bdescr *prev, *next;
for (t = 0; t < n_gc_threads; t++) {
thr = gc_threads[t];
// not step 0
for (s = 1; s < total_steps; s++) {
ws = &thr->steps[s];
- // Not true?
- // ASSERT( ws->scan_bd == ws->todo_bd );
- ASSERT( ws->scan_bd ? ws->scan == ws->scan_bd->free : 1 );
// Push the final block
- if (ws->scan_bd) { push_scan_block(ws->scan_bd, ws); }
-
+ if (ws->todo_bd) {
+ push_scanned_block(ws->todo_bd, ws);
+ }
+
+ ASSERT(gct->scan_bd == NULL);
ASSERT(countBlocks(ws->scavd_list) == ws->n_scavd_blocks);
- prev = ws->scavd_list;
+ prev = NULL;
for (bd = ws->scavd_list; bd != NULL; bd = bd->link) {
bd->flags &= ~BF_EVACUATED; // now from-space
+ ws->step->n_words += bd->free - bd->start;
prev = bd;
}
- prev->link = ws->stp->blocks;
- ws->stp->blocks = ws->scavd_list;
- ws->stp->n_blocks += ws->n_scavd_blocks;
- ASSERT(countBlocks(ws->stp->blocks) == ws->stp->n_blocks);
+ if (prev != NULL) {
+ prev->link = ws->step->blocks;
+ ws->step->blocks = ws->scavd_list;
+ }
+ ws->step->n_blocks += ws->n_scavd_blocks;
+
+ prev = NULL;
+ for (bd = ws->part_list; bd != NULL; bd = next) {
+ next = bd->link;
+ if (bd->free == bd->start) {
+ if (prev == NULL) {
+ ws->part_list = next;
+ } else {
+ prev->link = next;
+ }
+ freeGroup(bd);
+ ws->n_part_blocks--;
+ } else {
+ bd->flags &= ~BF_EVACUATED; // now from-space
+ ws->step->n_words += bd->free - bd->start;
+ prev = bd;
+ }
+ }
+ if (prev != NULL) {
+ prev->link = ws->step->blocks;
+ ws->step->blocks = ws->part_list;
+ }
+ ws->step->n_blocks += ws->n_part_blocks;
+
+ ASSERT(countBlocks(ws->step->blocks) == ws->step->n_blocks);
+ ASSERT(countOccupied(ws->step->blocks) == ws->step->n_words);
}
}
}
/* run through all the generations/steps and tidy up
*/
copied = 0;
+ max_copied = 0;
+ avg_copied = 0;
{
nat i;
for (i=0; i < n_gc_threads; i++) {
- if (major_gc) {
+ if (n_gc_threads > 1) {
trace(TRACE_gc,"thread %d:", i);
trace(TRACE_gc," copied %ld", gc_threads[i]->copied * sizeof(W_));
+ trace(TRACE_gc," scanned %ld", gc_threads[i]->scanned * sizeof(W_));
trace(TRACE_gc," any_work %ld", gc_threads[i]->any_work);
trace(TRACE_gc," no_work %ld", gc_threads[i]->no_work);
- trace(TRACE_gc," scav_global_work %ld", gc_threads[i]->scav_global_work);
- trace(TRACE_gc," scav_local_work %ld", gc_threads[i]->scav_local_work);
+ trace(TRACE_gc," scav_find_work %ld", gc_threads[i]->scav_find_work);
}
copied += gc_threads[i]->copied;
+ max_copied = stg_max(gc_threads[i]->copied, max_copied);
+ }
+ if (n_gc_threads == 1) {
+ max_copied = 0;
+ avg_copied = 0;
+ } else {
+ avg_copied = copied;
}
}
for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
- if (g <= N) {
+ if (g == N) {
generations[g].collections++; // for stats
+ if (n_gc_threads > 1) generations[g].par_collections++;
}
// Count the mutable list as bytes "copied" for the purposes of
// onto the front of the now-compacted existing blocks.
for (bd = stp->blocks; bd != NULL; bd = bd->link) {
bd->flags &= ~BF_EVACUATED; // now from-space
+ stp->n_words += bd->free - bd->start;
}
// tack the new blocks on the end of the existing blocks
if (stp->old_blocks != NULL) {
// add the new blocks to the block tally
stp->n_blocks += stp->n_old_blocks;
ASSERT(countBlocks(stp->blocks) == stp->n_blocks);
+ ASSERT(countOccupied(stp->blocks) == stp->n_words);
}
else // not copacted
{
// update the max size of older generations after a major GC
resize_generations();
- // Guess the amount of live data for stats.
- live = calcLiveBlocks() * BLOCK_SIZE_W;
- debugTrace(DEBUG_gc, "Slop: %ldKB",
- (live - calcLiveWords()) / (1024/sizeof(W_)));
+ // Calculate the amount of live data for stats.
+ live = calcLiveWords();
// Free the small objects allocated via allocate(), since this will
// all have been copied into G0S1 now.
g0s0->blocks = NULL;
}
g0s0->n_blocks = 0;
+ g0s0->n_words = 0;
}
alloc_blocks = 0;
alloc_blocks_lim = RtsFlags.GcFlags.minAllocAreaSize;
IF_DEBUG(sanity, checkSanity());
// extra GC trace info
- if (traceClass(TRACE_gc)) statDescribeGens();
+ if (traceClass(TRACE_gc|DEBUG_gc)) statDescribeGens();
#ifdef DEBUG
// symbol-table based profiling
#endif
// ok, GC over: tell the stats department what happened.
- stat_endGC(allocated, live, copied, N);
+ slop = calcLiveBlocks() * BLOCK_SIZE_W - live;
+ stat_endGC(allocated, live, copied, N, max_copied, avg_copied, slop);
#if defined(RTS_USER_SIGNALS)
if (RtsFlags.MiscFlags.install_signal_handlers) {
/* -----------------------------------------------------------------------------
Figure out which generation to collect, initialise N and major_gc.
+
+ Also returns the total number of blocks in generations that will be
+ collected.
-------------------------------------------------------------------------- */
-static void
+static nat
initialise_N (rtsBool force_major_gc)
{
- nat g;
+ int g;
+ nat s, blocks, blocks_total;
+
+ blocks = 0;
+ blocks_total = 0;
if (force_major_gc) {
- N = RtsFlags.GcFlags.generations - 1;
- major_gc = rtsTrue;
+ N = RtsFlags.GcFlags.generations - 1;
} else {
- N = 0;
- for (g = 0; g < RtsFlags.GcFlags.generations; g++) {
- if (generations[g].steps[0].n_blocks +
- generations[g].steps[0].n_large_blocks
- >= generations[g].max_blocks) {
- N = g;
- }
- }
- major_gc = (N == RtsFlags.GcFlags.generations-1);
+ N = 0;
}
+
+ for (g = RtsFlags.GcFlags.generations - 1; g >= 0; g--) {
+ blocks = 0;
+ for (s = 0; s < generations[g].n_steps; s++) {
+ blocks += generations[g].steps[s].n_words / BLOCK_SIZE_W;
+ blocks += generations[g].steps[s].n_large_blocks;
+ }
+ if (blocks >= generations[g].max_blocks) {
+ N = stg_max(N,g);
+ }
+ if ((nat)g <= N) {
+ blocks_total += blocks;
+ }
+ }
+
+ blocks_total += countNurseryBlocks();
+
+ major_gc = (N == RtsFlags.GcFlags.generations-1);
+ return blocks_total;
}
/* -----------------------------------------------------------------------------
t->id = 0;
initCondition(&t->wake_cond);
initMutex(&t->wake_mutex);
- t->wakeup = rtsFalse;
+ t->wakeup = rtsTrue; // starts true, so we can wait for the
+ // thread to start up, see wakeup_gc_threads
t->exit = rtsFalse;
#endif
for (s = 0; s < total_steps; s++)
{
ws = &t->steps[s];
- ws->stp = &all_steps[s];
- ASSERT(s == ws->stp->abs_no);
+ ws->step = &all_steps[s];
+ ASSERT(s == ws->step->abs_no);
ws->gct = t;
- ws->scan_bd = NULL;
- ws->scan = NULL;
-
ws->todo_bd = NULL;
ws->buffer_todo_bd = NULL;
+ ws->part_list = NULL;
+ ws->n_part_blocks = 0;
+
ws->scavd_list = NULL;
ws->n_scavd_blocks = 0;
}
ACQUIRE_LOCK(&gc_running_mutex);
n_running = ++gc_running_threads;
RELEASE_LOCK(&gc_running_mutex);
+ ASSERT(n_running <= n_gc_threads);
return n_running;
}
{
nat n_running;
ACQUIRE_LOCK(&gc_running_mutex);
+ ASSERT(n_gc_threads != 0);
n_running = --gc_running_threads;
RELEASE_LOCK(&gc_running_mutex);
return n_running;
gct->thread_index, r);
while (gc_running_threads != 0) {
+ usleep(1);
if (any_work()) {
inc_running();
goto loop;
// Wait until we're told to wake up
ACQUIRE_LOCK(&gct->wake_mutex);
+ gct->wakeup = rtsFalse;
while (!gct->wakeup) {
debugTrace(DEBUG_gc, "GC thread %d standing by...",
gct->thread_index);
waitCondition(&gct->wake_cond, &gct->wake_mutex);
}
RELEASE_LOCK(&gct->wake_mutex);
- gct->wakeup = rtsFalse;
if (gct->exit) break;
#ifdef USE_PAPI
nat i;
for (i=1; i < n_threads; i++) {
inc_running();
- ACQUIRE_LOCK(&gc_threads[i]->wake_mutex);
+ debugTrace(DEBUG_gc, "waking up gc thread %d", i);
+ do {
+ ACQUIRE_LOCK(&gc_threads[i]->wake_mutex);
+ if (gc_threads[i]->wakeup) {
+ RELEASE_LOCK(&gc_threads[i]->wake_mutex);
+ continue;
+ } else {
+ break;
+ }
+ } while (1);
gc_threads[i]->wakeup = rtsTrue;
signalCondition(&gc_threads[i]->wake_cond);
RELEASE_LOCK(&gc_threads[i]->wake_mutex);
#endif
}
+// After GC is complete, we must wait for all GC threads to enter the
+// standby state, otherwise they may still be executing inside
+// any_work(), and may even remain awake until the next GC starts.
+static void
+shutdown_gc_threads (nat n_threads USED_IF_THREADS)
+{
+#if defined(THREADED_RTS)
+ nat i;
+ rtsBool wakeup;
+ for (i=1; i < n_threads; i++) {
+ do {
+ ACQUIRE_LOCK(&gc_threads[i]->wake_mutex);
+ wakeup = gc_threads[i]->wakeup;
+ // wakeup is false while the thread is waiting
+ RELEASE_LOCK(&gc_threads[i]->wake_mutex);
+ } while (wakeup);
+ }
+#endif
+}
+
/* ----------------------------------------------------------------------------
Initialise a generation that is to be collected
------------------------------------------------------------------------- */
stp->n_old_blocks = stp->n_blocks;
stp->blocks = NULL;
stp->n_blocks = 0;
+ stp->n_words = 0;
// we don't have any to-be-scavenged blocks yet
stp->todos = NULL;
ws = &gc_threads[t]->steps[g * RtsFlags.GcFlags.steps + s];
- ws->scan_bd = NULL;
- ws->scan = NULL;
-
ws->todo_large_objects = NULL;
+ ws->part_list = NULL;
+ ws->n_part_blocks = 0;
+
// allocate the first to-space block; extra blocks will be
// chained on as necessary.
ws->todo_bd = NULL;
ws->buffer_todo_bd = NULL;
- gc_alloc_todo_block(ws);
+ alloc_todo_block(ws,0);
ws->scavd_list = NULL;
ws->n_scavd_blocks = 0;
for (s = 0; s < generations[g].n_steps; s++) {
ws = &gc_threads[t]->steps[g * RtsFlags.GcFlags.steps + s];
- stp = ws->stp;
+ stp = ws->step;
ws->buffer_todo_bd = NULL;
ws->todo_large_objects = NULL;
+ ws->part_list = NULL;
+ ws->n_part_blocks = 0;
+
ws->scavd_list = NULL;
ws->n_scavd_blocks = 0;
ws->todo_lim = ws->todo_bd->start + BLOCK_SIZE_W;
stp->blocks = stp->blocks->link;
stp->n_blocks -= 1;
+ stp->n_words -= ws->todo_bd->free - ws->todo_bd->start;
ws->todo_bd->link = NULL;
-
- // this block is also the scan block; we must scan
- // from the current end point.
- ws->scan_bd = ws->todo_bd;
- ws->scan = ws->scan_bd->free;
-
- // subtract the contents of this block from the stats,
- // because we'll count the whole block later.
- copied -= ws->scan_bd->free - ws->scan_bd->start;
+ // we must scan from the current end point.
+ ws->todo_bd->u.scan = ws->todo_bd->free;
}
else
{
- ws->scan_bd = NULL;
- ws->scan = NULL;
ws->todo_bd = NULL;
- gc_alloc_todo_block(ws);
+ alloc_todo_block(ws,0);
}
}
}
{
t->static_objects = END_OF_STATIC_LIST;
t->scavenged_static_objects = END_OF_STATIC_LIST;
+ t->scan_bd = NULL;
t->evac_step = 0;
t->failed_to_evac = rtsFalse;
t->eager_promotion = rtsTrue;
t->thunk_selector_depth = 0;
t->copied = 0;
+ t->scanned = 0;
t->any_work = 0;
t->no_work = 0;
- t->scav_global_work = 0;
- t->scav_local_work = 0;
-
+ t->scav_find_work = 0;
}
/* -----------------------------------------------------------------------------
nat gens = RtsFlags.GcFlags.generations;
// live in the oldest generations
- live = oldest_gen->steps[0].n_blocks +
+ live = (oldest_gen->steps[0].n_words + BLOCK_SIZE_W - 1) / BLOCK_SIZE_W+
oldest_gen->steps[0].n_large_blocks;
// default max size for all generations except zero
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