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Tweak getCurrentContext for SPEED #5959

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Merged
headius merged 1 commit into from
Nov 5, 2019
Merged

Tweak getCurrentContext for SPEED #5959

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8 changes: 4 additions & 4 deletions core/src/main/java/org/jruby/Ruby.java
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Original file line number Diff line number Diff line change
Expand Up @@ -2762,7 +2762,7 @@ public ThreadService getThreadService() {
}

public ThreadContext getCurrentContext() {
return threadService.getCurrentContext();
return ThreadService.getCurrentContext(threadService);
}

/**
Expand Down Expand Up @@ -3413,8 +3413,8 @@ public void tearDown(boolean systemExit) {
printProfileData(profileCollection);
}

// tear down thread references
getThreadService().teardown();
// swap with a new service to dereference all thread constructs
threadService = new ThreadService(this);

// shut down executors
getJITCompiler().shutdown();
Expand Down Expand Up @@ -5076,7 +5076,7 @@ private MRIRecursionGuard oldRecursionGuard() {
1 /* concurrency level - mostly reads here so this can be 1 */);

private final Invalidator checkpointInvalidator;
private final ThreadService threadService;
private ThreadService threadService;

private final POSIX posix;

Expand Down
65 changes: 33 additions & 32 deletions core/src/main/java/org/jruby/internal/runtime/ThreadService.java
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Original file line number Diff line number Diff line change
Expand Up @@ -49,7 +49,7 @@
import org.jruby.runtime.ThreadContext;

/**
* ThreadService maintains lists ofall the JRuby-specific thread data structures
* ThreadService maintains references to all JRuby-specific thread data structures
* needed for Ruby's threading API and for JRuby's execution. The main
* structures are:
*
Expand All @@ -66,7 +66,7 @@
* with these structures are:
*
* <ul>
* <li>ThreadService has a hard reference to a ThreadLocal, which holds a soft reference
* <li>ThreadService is itself a ThreadLocal, which holds a soft reference
* to a ThreadContext. So the thread's locals softly reference ThreadContext.
* We use a soft reference to keep ThreadContext instances from going away too
* quickly when a Java thread leaves Ruby space completely, which would otherwise
Expand Down Expand Up @@ -106,23 +106,14 @@
* releasing the hard reference to the Thread itself.</li>
* <ul>
*/
public class ThreadService {
public class ThreadService extends ThreadLocal<SoftReference<ThreadContext>> {
private final Ruby runtime;
/**
* A hard reference to the "main" context, so we always have one waiting for
* "main" thread execution.
*/
private ThreadContext mainContext;

/**
* A thread-local soft reference to the current thread's ThreadContext. We
* use a soft reference so that the ThreadContext is still collectible but
* will not immediately disappear once dereferenced, to avoid churning
* through ThreadContext instances every time a Java thread enters and exits
* Ruby space.
*/
private ThreadLocal<SoftReference<ThreadContext>> localContext;

/**
* The Java thread group into which we register all Ruby threads. This is
* distinct from the RubyThreadGroup, which is simply a mutable collection
Expand All @@ -144,7 +135,6 @@ public class ThreadService {

public ThreadService(final Ruby runtime) {
this.runtime = runtime;
this.localContext = new ThreadLocal<>();

try {
this.rubyThreadGroup = new ThreadGroup("Ruby Threads#" + runtime.hashCode());
Expand All @@ -156,9 +146,6 @@ public ThreadService(final Ruby runtime) {
}

public void teardown() {
// clear all thread-local context references
localContext = new ThreadLocal<>();

// clear main context reference
mainContext = null;

Expand All @@ -170,7 +157,7 @@ public void initMainThread() {
this.mainContext = ThreadContext.newContext(runtime);

// Must be called from main thread (it is currently, but this bothers me)
localContext.set(new SoftReference<>(mainContext));
set(new SoftReference<>(mainContext));
}

/**
Expand All @@ -197,24 +184,38 @@ public void initMainThread() {
* collected.
*/
public final ThreadContext getCurrentContext() {
return getCurrentContext(this);
}

public static ThreadContext getCurrentContext(ThreadService service) {
ThreadContext context;

// keep trying until we have a context
do {
SoftReference<ThreadContext> ref = localContext.get();
if (ref == null) {
context = adoptCurrentThread().getContext(); // registerNewThread will localContext.set(...)
} else {
if ((context = ref.get()) == null) {
// context is null, wipe out the SoftReference (this could be done with a reference queue)
localContext.set(null);
}
}
} while (context == null);
context = adoptLoop(service);

if (context == null) return getCurrentContext(service);

return context;
}

private static ThreadContext adoptLoop(ThreadService service) {
SoftReference<ThreadContext> ref = service.get();
if (ref == null) {
return contextFromAdopt(service); // registerNewThread will localContext.set(...)
} else {
ThreadContext context;
if ((context = ref.get()) == null) {
// context is null, wipe out the SoftReference (this could be done with a reference queue)
service.remove();
}
return context;
}
}

private static ThreadContext contextFromAdopt(ThreadService service) {
return service.adoptCurrentThread().getContext();
}

private RubyThread adoptCurrentThread() {
return RubyThread.adopt(runtime, this, Thread.currentThread());
}
Expand All @@ -224,7 +225,7 @@ public ThreadContext registerNewThread(RubyThread thread) {
ThreadContext context = ThreadContext.newContext(runtime);
context.setThread(thread);
ThreadFiber.initRootFiber(context, thread);
localContext.set(new SoftReference<>(context));
set(new SoftReference<>(context));
return context;
}

Expand Down Expand Up @@ -287,9 +288,9 @@ private void unregisterThreadImpl(ThreadContext context, Thread nativeThread) {
if (thread != null) thread.clearContext(); // help GC - clear context-ref
}

SoftReference<ThreadContext> ref = localContext.get();
SoftReference<ThreadContext> ref = get();
if (ref != null) ref.clear(); // help GC
localContext.remove();
remove();
}

@Deprecated // use unregisterCurrentThread
Expand Down Expand Up @@ -327,7 +328,7 @@ public synchronized void dissociateThread(Object threadOrFuture) {

@Deprecated
public final void setCurrentContext(ThreadContext context) {
localContext.set(new SoftReference<ThreadContext>(context));
set(new SoftReference<ThreadContext>(context));
}

@Deprecated
Expand Down