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Bump Cobalt version to enable single-threading 

The latest version of Cobalt has several major changes, which I'm
looking forward to taking advantage of in the coming months:

 - The Lua interpreter has been split up from the actual LuaClosure
   instance. It now runs multiple functions within one loop, handling
   pushing/popping and resuming method calls correctly.

   This means we have a theoretically infinite call depth, as we're no
   longer bounded by Java's stack size. In reality, this is limited to
   32767 (Short.MAX_VALUE), as that's a mostly equivalent to the limits
   PUC Lua exposes.

 - The stack is no longer unwound in the event of errors. This both
   simplifies error handling (not that CC:T needs to care about that)
   but also means one can call debug.traceback on a now-dead coroutine
   (which is more useful for debugging than using xpcall).

 - Most significantly, coroutines are no longer each run on a dedicated
   thread. Instead, yielding or resuming throws an exception to unwind
   the Java stack and switches to a different coroutine.

   In order to preserve compatability with CC's assumption about LuaJ's
   threading model (namely that yielding blocks the thread), we also
   provide a yieldBlock method (which CC:T consumes). This suspends the
   current thread and switches execution to a new thread (see
   SquidDev/Cobalt@b5ddf164f1 for more
   details). While this does mean we need to use more than 1 thread,
   it's still /substantially/ less than would otherwise be needed.

We've been running these changes on SwitchCraft for a few days now and
haven't seen any issues. One nice thing to observe is that the number of
CC thread has gone down from ~1.9k to ~100 (of those, ~70 are dedicated
to running coroutines). Similarly, the server has gone from generating
~15k threads over its lifetime, to ~3k. While this is still a lot, it's
a substantial improvement.
This commit is contained in:
SquidDev 2019-02-10 21:46:52 +00:00
parent 6c2db93cbd
commit 12e82afad2
3 changed files with 61 additions and 45 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
build.gradle
View File

@ -48,7 +48,7 @@
}
maven {
name = "squiddev"
url = "https://dl.bintray.com/squiddev/maven"
url = "https://squiddev.cc/maven"
}
ivy { artifactPattern "https://asie.pl/files/mods/Charset/LibOnly/[module]-[revision](-[classifier]).[ext]" }
@ -66,7 +66,7 @@
runtime "mezz.jei:jei_1.12.2:4.8.5.159"
shade 'org.squiddev:Cobalt:0.4.0'
shade 'org.squiddev:Cobalt:0.5.0-SNAPSHOT'
testCompile 'junit:junit:4.11'

42
src/main/java/dan200/computercraft/core/computer/ComputerThread.java
View File

@ -16,6 +16,7 @@
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.locks.LockSupport;
public class ComputerThread
{
@ -216,22 +217,37 @@ private void execute( BlockingQueue<ITask> queue ) throws InterruptedException
// Interrupt the thread
if( !done )
{
StringBuilder builder = new StringBuilder( "Terminating " );
if( computer != null )
if( ComputerCraft.logPeripheralErrors )
{
builder.append( "computer " ).append( computer.getID() );
}
else
{
builder.append( "unknown computer" );
}
long time = System.nanoTime() - start;
StringBuilder builder = new StringBuilder( "Terminating " );
if( computer != null )
{
builder.append( "computer #" ).append( computer.getID() );
}
else
{
builder.append( "unknown computer" );
}
builder.append( ". Thread is currently running" );
for( StackTraceElement element : thread.getStackTrace() )
{
builder.append( "\n at " ).append( element );
{
builder.append( " due to timeout (running for " )
.append( time / 1e9 )
.append( " seconds). This is NOT a bug, but may mean a computer is misbehaving. " )
.append( thread.getName() )
.append( " is currently " )
.append( thread.getState() );
Object blocking = LockSupport.getBlocker( thread );
if( blocking != null ) builder.append( "\n on " ).append( blocking );
for( StackTraceElement element : thread.getStackTrace() )
{
builder.append( "\n at " ).append( element );
}
}
ComputerCraft.log.warn( builder.toString() );
}
ComputerCraft.log.error( builder.toString() );
thread.interrupt();
thread = null;

60
src/main/java/dan200/computercraft/core/lua/CobaltLuaMachine.java
View File

@ -46,7 +46,7 @@ public class CobaltLuaMachine implements ILuaMachine
{
private static final ThreadPoolExecutor coroutines = new ThreadPoolExecutor(
0, Integer.MAX_VALUE,
60L, TimeUnit.SECONDS,
5L, TimeUnit.MINUTES,
new SynchronousQueue<>(),
ThreadUtils.factory( "Coroutine" )
);
@ -74,12 +74,12 @@ public CobaltLuaMachine( Computer computer )
private boolean hasSoftAbort;
@Override
public void onInstruction( DebugState ds, DebugFrame di, int pc, Varargs extras, int top ) throws LuaError
public void onInstruction( DebugState ds, DebugFrame di, int pc ) throws LuaError, UnwindThrowable
{
int count = ++this.count;
if( count > 100000 )
{
if( m_hardAbortMessage != null ) LuaThread.yield( m_state, NONE );
if( m_hardAbortMessage != null ) throw HardAbortError.INSTANCE;
this.count = 0;
}
else
@ -87,13 +87,13 @@ public void onInstruction( DebugState ds, DebugFrame di, int pc, Varargs extras,
handleSoftAbort();
}
super.onInstruction( ds, di, pc, extras, top );
super.onInstruction( ds, di, pc );
}
@Override
public void poll() throws LuaError
{
if( m_hardAbortMessage != null ) LuaThread.yield( m_state, NONE );
if( m_hardAbortMessage != null ) throw HardAbortError.INSTANCE;
handleSoftAbort();
}
@ -117,7 +117,7 @@ private void handleSoftAbort() throws LuaError
throw new LuaError( message );
}
} )
.coroutineFactory( command -> {
.yieldThreader( command -> {
Tracking.addValue( m_computer, TrackingField.COROUTINES_CREATED, 1 );
coroutines.execute( () -> {
try
@ -145,7 +145,7 @@ private void handleSoftAbort() throws LuaError
if( ComputerCraft.debug_enable ) m_globals.load( state, new DebugLib() );
// Register custom load/loadstring provider which automatically adds prefixes.
LibFunction.bind( state, m_globals, PrefixLoader.class, new String[] { "load", "loadstring" } );
LibFunction.bind( m_globals, PrefixLoader.class, new String[] { "load", "loadstring" } );
// Remove globals we don't want to expose
m_globals.rawset( "collectgarbage", Constants.NIL );
@ -222,26 +222,18 @@ public void handleEvent( String eventName, Object[] arguments )
resumeArgs = varargsOf( valueOf( eventName ), toValues( arguments ) );
}
Varargs results = m_mainRoutine.resume( resumeArgs );
if( m_hardAbortMessage != null )
{
throw new LuaError( m_hardAbortMessage );
}
else if( !results.first().checkBoolean() )
{
throw new LuaError( results.arg( 2 ).checkString() );
}
else
{
LuaValue filter = results.arg( 2 );
m_eventFilter = filter.isString() ? filter.toString() : null;
}
Varargs results = LuaThread.run( m_mainRoutine, resumeArgs );
if( m_hardAbortMessage != null ) throw new LuaError( m_hardAbortMessage );
LuaValue filter = results.first();
m_eventFilter = filter.isString() ? filter.toString() : null;
if( m_mainRoutine.getStatus().equals( "dead" ) ) unload();
}
catch( LuaError e )
catch( LuaError | HardAbortError e )
{
unload();
ComputerCraft.log.warn( "Top level coroutine errored", e );
}
finally
{
@ -339,16 +331,12 @@ public Object[] yield( Object[] yieldArgs ) throws InterruptedException
{
try
{
Varargs results = LuaThread.yield( state, toValues( yieldArgs ) );
Varargs results = LuaThread.yieldBlocking( state, toValues( yieldArgs ) );
return toObjects( results, 1 );
}
catch( OrphanedThread e )
catch( LuaError e )
{
throw new InterruptedException();
}
catch( Throwable e )
{
throw new RuntimeException( e );
throw new IllegalStateException( e );
}
}
@ -699,7 +687,7 @@ public int read() throws IOException
LuaValue s;
try
{
s = OperationHelper.call( state, func );
s = OperationHelper.noYield( state, () -> OperationHelper.call( state, func ) );
}
catch( LuaError e )
{
@ -731,4 +719,16 @@ public int read() throws IOException
return bytes[offset++];
}
}
private static class HardAbortError extends Error
{
private static final long serialVersionUID = 7954092008586367501L;
public static final HardAbortError INSTANCE = new HardAbortError();
private HardAbortError()
{
super( "Hard Abort", null, true, false );
}
}
}