Fabio/brouter
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http server: do not terminate old thread when threads limit reached

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Original implementation of the thread pool was limiting max number of
threads by terminating oldest thread if the limit was already reached and
a new request has arrived. This was causing broken responses under load.
Instead we now wait until one of the threads completes before starting a
new one.
This commit is contained in:
Sergej Orlov 2020-02-02 16:19:56 +01:00
parent 179525712f
commit 24d0e97c34
1 changed files with 6 additions and 40 deletions
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46
brouter-server/src/main/java/btools/server/RouteServer.java
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@ -15,6 +15,7 @@ import java.net.Socket;
import java.net.URLDecoder;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.concurrent.Semaphore;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
@ -46,14 +47,8 @@ public class RouteServer extends Thread
private Socket clientSocket = null;
private RoutingEngine cr = null;
private volatile boolean terminated;
private Semaphore semaphore = null;
public void stopRouter()
{
RoutingEngine e = cr;
if ( e != null ) e.terminate();
}
private static DateFormat tsFormat = new SimpleDateFormat( "dd.MM.yy HH:mm", new Locale( "en", "US" ) );
private static String formattedTimestamp()
@ -270,7 +265,7 @@ public class RouteServer extends Thread
if ( br != null ) try { br.close(); } catch( Exception e ) {}
if ( bw != null ) try { bw.close(); } catch( Exception e ) {}
if ( clientSocket != null ) try { clientSocket.close(); } catch( Exception e ) {}
terminated = true;
semaphore.release();
}
}
@ -294,8 +289,7 @@ public class RouteServer extends Thread
serviceContext.sharedProfileDir = tk.hasMoreTokens() ? tk.nextToken() : serviceContext.customProfileDir;
int maxthreads = Integer.parseInt( args[4] );
TreeMap<Long,RouteServer> threadMap = new TreeMap<Long,RouteServer>();
Semaphore semaphore = new Semaphore(maxthreads, true);
ServerSocket serverSocket = args.length > 5 ? new ServerSocket(Integer.parseInt(args[3]),50,InetAddress.getByName(args[5])) : new ServerSocket(Integer.parseInt(args[3]));
@ -318,36 +312,8 @@ public class RouteServer extends Thread
RouteServer server = new RouteServer();
server.serviceContext = serviceContext;
server.clientSocket = clientSocket;
// cleanup thread list
for(;;)
{
boolean removedItem = false;
for (Map.Entry<Long,RouteServer> e : threadMap.entrySet())
{
if ( e.getValue().terminated )
{
threadMap.remove( e.getKey() );
removedItem = true;
break;
}
}
if ( !removedItem ) break;
}
// kill thread if limit reached
if ( threadMap.size() >= maxthreads )
{
Long k = threadMap.firstKey();
RouteServer victim = threadMap.get( k );
threadMap.remove( k );
victim.stopRouter();
}
long ts = System.currentTimeMillis();
while ( ts <= last_ts ) ts++;
threadMap.put( Long.valueOf( ts ), server );
last_ts = ts;
server.semaphore = semaphore;
semaphore.acquire();
server.start();
}
}