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fix use of jl_n_threads in gc; scale default collect interval #32633

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Jul 22, 2019
Merged

fix use of jl_n_threads in gc; scale default collect interval #32633

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3 changes: 1 addition & 2 deletions base/util.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -35,8 +35,7 @@ struct GC_Diff
end

gc_total_bytes(gc_num::GC_Num) =
(gc_num.allocd + gc_num.deferred_alloc +
Int64(gc_num.collect) + Int64(gc_num.total_allocd))
(gc_num.allocd + gc_num.deferred_alloc + Int64(gc_num.total_allocd))

function GC_Diff(new::GC_Num, old::GC_Num)
# logic from `src/gc.c:jl_gc_total_bytes`
Expand Down
50 changes: 15 additions & 35 deletions src/gc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -494,19 +494,6 @@ static size_t max_collect_interval = 1250000000UL;
static size_t max_collect_interval = 500000000UL;
#endif

// determine how often the given thread should atomically update
// the global allocation counter.
// NOTE: currently the same for all threads.
static int64_t per_thread_counter_interval(jl_ptls_t ptls) JL_NOTSAFEPOINT
{
if (jl_n_threads == 1)
return gc_num.interval;
size_t intvl = gc_num.interval / jl_n_threads / 2;
if (intvl < 1048576)
return 1048576;
return intvl;
}

// global variables for GC stats

// Resetting the object to a young object, this is used when marking the
Expand Down Expand Up @@ -796,14 +783,7 @@ void jl_gc_force_mark_old(jl_ptls_t ptls, jl_value_t *v) JL_NOTSAFEPOINT

static inline void maybe_collect(jl_ptls_t ptls)
{
int should_collect = 0;
if (ptls->gc_num.allocd >= 0) {
int64_t intvl = per_thread_counter_interval(ptls);
size_t localbytes = ptls->gc_num.allocd + intvl;
ptls->gc_num.allocd = -intvl;
should_collect = (jl_atomic_add_fetch(&gc_num.allocd, localbytes) >= 0);
}
if (should_collect || gc_debug_check_other()) {
if (ptls->gc_num.allocd >= 0 || gc_debug_check_other()) {
jl_gc_collect(0);
}
else {
Expand Down Expand Up @@ -975,7 +955,7 @@ static void combine_thread_gc_counts(jl_gc_num_t *dest) JL_NOTSAFEPOINT
for (int i = 0; i < jl_n_threads; i++) {
jl_ptls_t ptls = jl_all_tls_states[i];
if (ptls) {
dest->allocd += (jl_atomic_load_relaxed(&ptls->gc_num.allocd) + per_thread_counter_interval(ptls));
dest->allocd += (jl_atomic_load_relaxed(&ptls->gc_num.allocd) + gc_num.interval);
dest->freed += jl_atomic_load_relaxed(&ptls->gc_num.freed);
dest->malloc += jl_atomic_load_relaxed(&ptls->gc_num.malloc);
dest->realloc += jl_atomic_load_relaxed(&ptls->gc_num.realloc);
Expand All @@ -992,16 +972,16 @@ static void reset_thread_gc_counts(void) JL_NOTSAFEPOINT
jl_ptls_t ptls = jl_all_tls_states[i];
if (ptls) {
memset(&ptls->gc_num, 0, sizeof(jl_thread_gc_num_t));
ptls->gc_num.allocd = -per_thread_counter_interval(ptls);
ptls->gc_num.allocd = -(int64_t)gc_num.interval;
}
}
}

void jl_gc_reset_alloc_count(void) JL_NOTSAFEPOINT
{
combine_thread_gc_counts(&gc_num);
live_bytes += (gc_num.deferred_alloc + (gc_num.allocd + gc_num.interval));
gc_num.allocd = -(int64_t)gc_num.interval;
live_bytes += (gc_num.deferred_alloc + gc_num.allocd);
gc_num.allocd = 0;
gc_num.deferred_alloc = 0;
reset_thread_gc_counts();
}
Expand Down Expand Up @@ -2622,8 +2602,7 @@ JL_DLLEXPORT int64_t jl_gc_total_bytes(void)
jl_gc_num_t num = gc_num;
combine_thread_gc_counts(&num);
// Sync this logic with `base/util.jl:GC_Diff`
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todo?

return (num.total_allocd + num.deferred_alloc +
num.allocd + num.interval);
return (num.total_allocd + num.deferred_alloc + num.allocd);
}
JL_DLLEXPORT uint64_t jl_gc_total_hrtime(void)
{
Expand Down Expand Up @@ -2742,7 +2721,7 @@ static int _jl_gc_collect(jl_ptls_t ptls, int full)
}
gc_mark_loop(ptls, sp);
gc_mark_sp_init(gc_cache, &sp);
gc_num.since_sweep += gc_num.allocd + (int64_t)gc_num.interval;
gc_num.since_sweep += gc_num.allocd;
gc_settime_premark_end();
gc_time_mark_pause(t0, scanned_bytes, perm_scanned_bytes);
int64_t actual_allocd = gc_num.since_sweep;
Expand Down Expand Up @@ -2892,7 +2871,7 @@ static int _jl_gc_collect(jl_ptls_t ptls, int full)
gc_time_sweep_pause(gc_end_t, actual_allocd, live_bytes,
estimate_freed, sweep_full);
gc_num.full_sweep += sweep_full;
gc_num.allocd = -(int64_t)gc_num.interval;
gc_num.allocd = 0;
last_live_bytes = live_bytes;
live_bytes += -gc_num.freed + gc_num.since_sweep;
if (prev_sweep_full) {
Expand All @@ -2913,8 +2892,9 @@ JL_DLLEXPORT void jl_gc_collect(int full)
{
jl_ptls_t ptls = jl_get_ptls_states();
if (jl_gc_disable_counter) {
gc_num.deferred_alloc += (gc_num.allocd + gc_num.interval);
gc_num.allocd = -(int64_t)gc_num.interval;
size_t localbytes = ptls->gc_num.allocd + gc_num.interval;
ptls->gc_num.allocd = -(int64_t)gc_num.interval;
jl_atomic_add_fetch(&gc_num.deferred_alloc, localbytes);
return;
}
gc_debug_print();
Expand Down Expand Up @@ -3017,7 +2997,7 @@ void jl_init_thread_heap(jl_ptls_t ptls)

memset(&ptls->gc_num, 0, sizeof(jl_thread_gc_num_t));
assert(gc_num.interval == default_collect_interval);
ptls->gc_num.allocd = -per_thread_counter_interval(ptls);
ptls->gc_num.allocd = -(int64_t)gc_num.interval;
}

// System-wide initializations
Expand All @@ -3031,11 +3011,11 @@ void jl_gc_init(void)

gc_num.interval = default_collect_interval;
last_long_collect_interval = default_collect_interval;
gc_num.allocd = -default_collect_interval;
gc_num.allocd = 0;

#ifdef _P64
// on a big memory machine, set max_collect_interval to totalmem * nthreads / ncores / 2
size_t maxmem = (uv_get_total_memory() * jl_n_threads) / jl_cpu_threads() / 2;
// on a big memory machine, set max_collect_interval to totalmem / ncores / 2
size_t maxmem = uv_get_total_memory() / jl_cpu_threads() / 2;
if (maxmem > max_collect_interval)
max_collect_interval = maxmem;
#endif
Expand Down