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8027593: performance drop with constrained codecache starting with hs25 b111
Fixed proper sweeping of small code cache sizes Reviewed-by: kvn, iveresov
This commit is contained in:
Albert Noll
parent
c632cad9d5
commit
18ca4cc301
7 changed files with 184 additions and 121 deletions
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@ -112,14 +112,13 @@ void NMethodSweeper::record_sweep(nmethod* nm, int line) {
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if (_records != NULL) {
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_records[_sweep_index].traversal = _traversals;
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_records[_sweep_index].traversal_mark = nm->_stack_traversal_mark;
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_records[_sweep_index].invocation = _invocations;
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_records[_sweep_index].invocation = _sweep_fractions_left;
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_records[_sweep_index].compile_id = nm->compile_id();
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_records[_sweep_index].kind = nm->compile_kind();
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_records[_sweep_index].state = nm->_state;
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_records[_sweep_index].vep = nm->verified_entry_point();
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_records[_sweep_index].uep = nm->entry_point();
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_records[_sweep_index].line = line;
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_sweep_index = (_sweep_index + 1) % SweeperLogEntries;
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}
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}
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@ -127,26 +126,29 @@ void NMethodSweeper::record_sweep(nmethod* nm, int line) {
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#define SWEEP(nm)
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#endif
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nmethod* NMethodSweeper::_current = NULL; // Current nmethod
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long NMethodSweeper::_traversals = 0; // Nof. stack traversals performed
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int NMethodSweeper::_seen = 0; // Nof. nmethods we have currently processed in current pass of CodeCache
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int NMethodSweeper::_flushed_count = 0; // Nof. nmethods flushed in current sweep
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int NMethodSweeper::_zombified_count = 0; // Nof. nmethods made zombie in current sweep
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int NMethodSweeper::_marked_count = 0; // Nof. nmethods marked for reclaim in current sweep
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nmethod* NMethodSweeper::_current = NULL; // Current nmethod
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long NMethodSweeper::_traversals = 0; // Stack scan count, also sweep ID.
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long NMethodSweeper::_time_counter = 0; // Virtual time used to periodically invoke sweeper
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long NMethodSweeper::_last_sweep = 0; // Value of _time_counter when the last sweep happened
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int NMethodSweeper::_seen = 0; // Nof. nmethod we have currently processed in current pass of CodeCache
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int NMethodSweeper::_flushed_count = 0; // Nof. nmethods flushed in current sweep
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int NMethodSweeper::_zombified_count = 0; // Nof. nmethods made zombie in current sweep
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int NMethodSweeper::_marked_for_reclamation_count = 0; // Nof. nmethods marked for reclaim in current sweep
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volatile int NMethodSweeper::_invocations = 0; // Nof. invocations left until we are completed with this pass
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volatile int NMethodSweeper::_sweep_started = 0; // Whether a sweep is in progress.
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volatile bool NMethodSweeper::_should_sweep = true; // Indicates if we should invoke the sweeper
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volatile int NMethodSweeper::_sweep_fractions_left = 0; // Nof. invocations left until we are completed with this pass
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volatile int NMethodSweeper::_sweep_started = 0; // Flag to control conc sweeper
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volatile int NMethodSweeper::_bytes_changed = 0; // Counts the total nmethod size if the nmethod changed from:
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// 1) alive -> not_entrant
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// 2) not_entrant -> zombie
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// 3) zombie -> marked_for_reclamation
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jint NMethodSweeper::_locked_seen = 0;
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jint NMethodSweeper::_not_entrant_seen_on_stack = 0;
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bool NMethodSweeper::_request_mark_phase = false;
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int NMethodSweeper::_total_nof_methods_reclaimed = 0;
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jlong NMethodSweeper::_total_time_sweeping = 0;
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jlong NMethodSweeper::_total_time_this_sweep = 0;
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jlong NMethodSweeper::_peak_sweep_time = 0;
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jlong NMethodSweeper::_peak_sweep_fraction_time = 0;
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int NMethodSweeper::_hotness_counter_reset_val = 0;
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int NMethodSweeper::_total_nof_methods_reclaimed = 0; // Accumulated nof methods flushed
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jlong NMethodSweeper::_total_time_sweeping = 0; // Accumulated time sweeping
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jlong NMethodSweeper::_total_time_this_sweep = 0; // Total time this sweep
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jlong NMethodSweeper::_peak_sweep_time = 0; // Peak time for a full sweep
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jlong NMethodSweeper::_peak_sweep_fraction_time = 0; // Peak time sweeping one fraction
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int NMethodSweeper::_hotness_counter_reset_val = 0;
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class MarkActivationClosure: public CodeBlobClosure {
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@ -197,13 +199,16 @@ void NMethodSweeper::mark_active_nmethods() {
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return;
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}
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// Increase time so that we can estimate when to invoke the sweeper again.
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_time_counter++;
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// Check for restart
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assert(CodeCache::find_blob_unsafe(_current) == _current, "Sweeper nmethod cached state invalid");
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if (!sweep_in_progress() && need_marking_phase()) {
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_seen = 0;
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_invocations = NmethodSweepFraction;
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_current = CodeCache::first_nmethod();
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_traversals += 1;
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if (!sweep_in_progress()) {
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_seen = 0;
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_sweep_fractions_left = NmethodSweepFraction;
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_current = CodeCache::first_nmethod();
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_traversals += 1;
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_total_time_this_sweep = 0;
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if (PrintMethodFlushing) {
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@ -211,10 +216,6 @@ void NMethodSweeper::mark_active_nmethods() {
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}
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Threads::nmethods_do(&mark_activation_closure);
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// reset the flags since we started a scan from the beginning.
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reset_nmethod_marking();
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_locked_seen = 0;
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_not_entrant_seen_on_stack = 0;
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} else {
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// Only set hotness counter
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Threads::nmethods_do(&set_hotness_closure);
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@ -222,14 +223,48 @@ void NMethodSweeper::mark_active_nmethods() {
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OrderAccess::storestore();
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}
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/**
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* This function invokes the sweeper if at least one of the three conditions is met:
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* (1) The code cache is getting full
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* (2) There are sufficient state changes in/since the last sweep.
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* (3) We have not been sweeping for 'some time'
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*/
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void NMethodSweeper::possibly_sweep() {
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assert(JavaThread::current()->thread_state() == _thread_in_vm, "must run in vm mode");
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if (!MethodFlushing || !sweep_in_progress()) {
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return;
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}
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if (_invocations > 0) {
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// If there was no state change while nmethod sweeping, 'should_sweep' will be false.
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// This is one of the two places where should_sweep can be set to true. The general
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// idea is as follows: If there is enough free space in the code cache, there is no
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// need to invoke the sweeper. The following formula (which determines whether to invoke
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// the sweeper or not) depends on the assumption that for larger ReservedCodeCacheSizes
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// we need less frequent sweeps than for smaller ReservedCodecCacheSizes. Furthermore,
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// the formula considers how much space in the code cache is currently used. Here are
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// some examples that will (hopefully) help in understanding.
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//
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// Small ReservedCodeCacheSizes: (e.g., < 16M) We invoke the sweeper every time, since
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// the result of the division is 0. This
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// keeps the used code cache size small
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// (important for embedded Java)
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// Large ReservedCodeCacheSize : (e.g., 256M + code cache is 10% full). The formula
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// computes: (256 / 16) - 1 = 15
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// As a result, we invoke the sweeper after
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// 15 invocations of 'mark_active_nmethods.
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// Large ReservedCodeCacheSize: (e.g., 256M + code Cache is 90% full). The formula
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// computes: (256 / 16) - 10 = 6.
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if (!_should_sweep) {
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int time_since_last_sweep = _time_counter - _last_sweep;
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double wait_until_next_sweep = (ReservedCodeCacheSize / (16 * M)) - time_since_last_sweep -
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CodeCache::reverse_free_ratio();
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if ((wait_until_next_sweep <= 0.0) || !CompileBroker::should_compile_new_jobs()) {
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_should_sweep = true;
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}
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}
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if (_should_sweep && _sweep_fractions_left > 0) {
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// Only one thread at a time will sweep
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jint old = Atomic::cmpxchg( 1, &_sweep_started, 0 );
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if (old != 0) {
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@ -242,31 +277,46 @@ void NMethodSweeper::possibly_sweep() {
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memset(_records, 0, sizeof(SweeperRecord) * SweeperLogEntries);
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}
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#endif
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if (_invocations > 0) {
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if (_sweep_fractions_left > 0) {
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sweep_code_cache();
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_invocations--;
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_sweep_fractions_left--;
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}
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// We are done with sweeping the code cache once.
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if (_sweep_fractions_left == 0) {
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_last_sweep = _time_counter;
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// Reset flag; temporarily disables sweeper
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_should_sweep = false;
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// If there was enough state change, 'possibly_enable_sweeper()'
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// sets '_should_sweep' to true
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possibly_enable_sweeper();
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// Reset _bytes_changed only if there was enough state change. _bytes_changed
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// can further increase by calls to 'report_state_change'.
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if (_should_sweep) {
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_bytes_changed = 0;
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}
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}
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_sweep_started = 0;
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}
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}
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void NMethodSweeper::sweep_code_cache() {
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jlong sweep_start_counter = os::elapsed_counter();
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_flushed_count = 0;
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_zombified_count = 0;
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_marked_count = 0;
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_flushed_count = 0;
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_zombified_count = 0;
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_marked_for_reclamation_count = 0;
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if (PrintMethodFlushing && Verbose) {
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tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _invocations);
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tty->print_cr("### Sweep at %d out of %d. Invocations left: %d", _seen, CodeCache::nof_nmethods(), _sweep_fractions_left);
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}
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if (!CompileBroker::should_compile_new_jobs()) {
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// If we have turned off compilations we might as well do full sweeps
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// in order to reach the clean state faster. Otherwise the sleeping compiler
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// threads will slow down sweeping.
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_invocations = 1;
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_sweep_fractions_left = 1;
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}
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// We want to visit all nmethods after NmethodSweepFraction
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@ -274,7 +324,7 @@ void NMethodSweeper::sweep_code_cache() {
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// remaining number of invocations. This is only an estimate since
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// the number of nmethods changes during the sweep so the final
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// stage must iterate until it there are no more nmethods.
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int todo = (CodeCache::nof_nmethods() - _seen) / _invocations;
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int todo = (CodeCache::nof_nmethods() - _seen) / _sweep_fractions_left;
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int swept_count = 0;
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@ -286,11 +336,11 @@ void NMethodSweeper::sweep_code_cache() {
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MutexLockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
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// The last invocation iterates until there are no more nmethods
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for (int i = 0; (i < todo || _invocations == 1) && _current != NULL; i++) {
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for (int i = 0; (i < todo || _sweep_fractions_left == 1) && _current != NULL; i++) {
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swept_count++;
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if (SafepointSynchronize::is_synchronizing()) { // Safepoint request
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if (PrintMethodFlushing && Verbose) {
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tty->print_cr("### Sweep at %d out of %d, invocation: %d, yielding to safepoint", _seen, CodeCache::nof_nmethods(), _invocations);
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tty->print_cr("### Sweep at %d out of %d, invocation: %d, yielding to safepoint", _seen, CodeCache::nof_nmethods(), _sweep_fractions_left);
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}
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MutexUnlockerEx mu(CodeCache_lock, Mutex::_no_safepoint_check_flag);
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@ -314,19 +364,7 @@ void NMethodSweeper::sweep_code_cache() {
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}
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}
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assert(_invocations > 1 || _current == NULL, "must have scanned the whole cache");
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if (!sweep_in_progress() && !need_marking_phase() && (_locked_seen || _not_entrant_seen_on_stack)) {
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// we've completed a scan without making progress but there were
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// nmethods we were unable to process either because they were
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// locked or were still on stack. We don't have to aggressively
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// clean them up so just stop scanning. We could scan once more
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// but that complicates the control logic and it's unlikely to
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// matter much.
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if (PrintMethodFlushing) {
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tty->print_cr("### Couldn't make progress on some nmethods so stopping sweep");
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}
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}
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assert(_sweep_fractions_left > 1 || _current == NULL, "must have scanned the whole cache");
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jlong sweep_end_counter = os::elapsed_counter();
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jlong sweep_time = sweep_end_counter - sweep_start_counter;
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@ -340,21 +378,21 @@ void NMethodSweeper::sweep_code_cache() {
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event.set_starttime(sweep_start_counter);
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event.set_endtime(sweep_end_counter);
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event.set_sweepIndex(_traversals);
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event.set_sweepFractionIndex(NmethodSweepFraction - _invocations + 1);
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event.set_sweepFractionIndex(NmethodSweepFraction - _sweep_fractions_left + 1);
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event.set_sweptCount(swept_count);
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event.set_flushedCount(_flushed_count);
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event.set_markedCount(_marked_count);
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event.set_markedCount(_marked_for_reclamation_count);
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event.set_zombifiedCount(_zombified_count);
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event.commit();
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}
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#ifdef ASSERT
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if(PrintMethodFlushing) {
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tty->print_cr("### sweeper: sweep time(%d): " INT64_FORMAT, _invocations, (jlong)sweep_time);
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tty->print_cr("### sweeper: sweep time(%d): " INT64_FORMAT, _sweep_fractions_left, (jlong)sweep_time);
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}
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#endif
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if (_invocations == 1) {
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if (_sweep_fractions_left == 1) {
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_peak_sweep_time = MAX2(_peak_sweep_time, _total_time_this_sweep);
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log_sweep("finished");
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}
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@ -368,12 +406,37 @@ void NMethodSweeper::sweep_code_cache() {
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// it only makes sense to re-enable compilation if we have actually freed memory.
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// Note that typically several kB are released for sweeping 16MB of the code
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// cache. As a result, 'freed_memory' > 0 to restart the compiler.
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if (UseCodeCacheFlushing && (!CompileBroker::should_compile_new_jobs() && (freed_memory > 0))) {
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if (!CompileBroker::should_compile_new_jobs() && (freed_memory > 0)) {
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CompileBroker::set_should_compile_new_jobs(CompileBroker::run_compilation);
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log_sweep("restart_compiler");
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}
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}
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/**
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* This function updates the sweeper statistics that keep track of nmethods
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* state changes. If there is 'enough' state change, the sweeper is invoked
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* as soon as possible. There can be data races on _bytes_changed. The data
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* races are benign, since it does not matter if we loose a couple of bytes.
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* In the worst case we call the sweeper a little later. Also, we are guaranteed
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* to invoke the sweeper if the code cache gets full.
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*/
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void NMethodSweeper::report_state_change(nmethod* nm) {
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_bytes_changed += nm->total_size();
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possibly_enable_sweeper();
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}
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/**
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* Function determines if there was 'enough' state change in the code cache to invoke
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* the sweeper again. Currently, we determine 'enough' as more than 1% state change in
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* the code cache since the last sweep.
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*/
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void NMethodSweeper::possibly_enable_sweeper() {
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double percent_changed = ((double)_bytes_changed / (double)ReservedCodeCacheSize) * 100;
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if (percent_changed > 1.0) {
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_should_sweep = true;
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}
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}
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class NMethodMarker: public StackObj {
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private:
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CompilerThread* _thread;
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@ -424,9 +487,6 @@ int NMethodSweeper::process_nmethod(nmethod *nm) {
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MutexLocker cl(CompiledIC_lock);
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nm->cleanup_inline_caches();
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SWEEP(nm);
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} else {
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_locked_seen++;
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SWEEP(nm);
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}
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return freed_memory;
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}
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@ -448,8 +508,9 @@ int NMethodSweeper::process_nmethod(nmethod *nm) {
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tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (zombie) being marked for reclamation", nm->compile_id(), nm);
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}
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nm->mark_for_reclamation();
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request_nmethod_marking();
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_marked_count++;
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// Keep track of code cache state change
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_bytes_changed += nm->total_size();
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_marked_for_reclamation_count++;
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SWEEP(nm);
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}
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} else if (nm->is_not_entrant()) {
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@ -459,18 +520,14 @@ int NMethodSweeper::process_nmethod(nmethod *nm) {
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if (PrintMethodFlushing && Verbose) {
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tty->print_cr("### Nmethod %3d/" PTR_FORMAT " (not entrant) being made zombie", nm->compile_id(), nm);
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}
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// Code cache state change is tracked in make_zombie()
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nm->make_zombie();
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request_nmethod_marking();
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_zombified_count++;
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SWEEP(nm);
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} else {
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// Still alive, clean up its inline caches
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MutexLocker cl(CompiledIC_lock);
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nm->cleanup_inline_caches();
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// we coudn't transition this nmethod so don't immediately
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// request a rescan. If this method stays on the stack for a
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// long time we don't want to keep rescanning the code cache.
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_not_entrant_seen_on_stack++;
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SWEEP(nm);
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}
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} else if (nm->is_unloaded()) {
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@ -485,8 +542,8 @@ int NMethodSweeper::process_nmethod(nmethod *nm) {
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release_nmethod(nm);
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_flushed_count++;
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} else {
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// Code cache state change is tracked in make_zombie()
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nm->make_zombie();
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request_nmethod_marking();
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_zombified_count++;
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SWEEP(nm);
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}
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@ -514,7 +571,11 @@ int NMethodSweeper::process_nmethod(nmethod *nm) {
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// The second condition ensures that methods are not immediately made not-entrant
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// after compilation.
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nm->make_not_entrant();
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request_nmethod_marking();
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// Code cache state change is tracked in make_not_entrant()
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if (PrintMethodFlushing && Verbose) {
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tty->print_cr("### Nmethod %d/" PTR_FORMAT "made not-entrant: hotness counter %d/%d threshold %f",
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nm->compile_id(), nm, nm->hotness_counter(), reset_val, threshold);
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}
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}
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}
|
||||
}
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue