On Sun, Dec 27, 2020 at 4:16 PM Romain Manni-Bucau <rmannibu...@gmail.com>
wrote:
> Hi everyone,
>
> wonder if there is some work planned in tomcat 10 to 1. makes it start
> faster and 2. make jmx optional.
>
> I did some tests and locally a tomcat start is about 400ms.
> I was surprised to see that Registry.disableRegistry() was taking already
> 65ms whereas it should be almost nothing so refactored the code, added a
> RegistryFactory and really noop impl (not even a mock) and went down to
> 1ms, way better right? except the remaining 64ms went to the next line (new
> StandardHost()). After some investigation time is mainly classloading time
> (in all senses).
>
> So I wonder if it wouldnt make sense to optimize tomcat startup time +
> finally make JMX optional since it is no more used by users in most cases -
> gues we must keep it as an optional plugin since it is used "historically".
>
> The proposal would be to:
>
> 1. reduce classloading tree as much as possible for default case - here
> having jmx optional will help a lot
> 2. probably generate resource bundle as .java at build time to avoid all
> the classloading resource bundle implies (it is like 74 loadClass + as much
> getResource for a simple startup and all loadclass are misses)
> 2.bis. probably add a mode where StringManager uses the default bundle
> without passing through the resource bundle layer
> 3. cut dead code when we know it is inactive (typically the case for jmx)
> 4. open point: bypassing Context: in "main" mode (as the code shared
> after), you just want to bind some logic in a servlet/filter/valve, you
> don't always care about handling contexts (or a single one) so wonder if we
> shouldnt evaluate the fact to add the user logic in a valve for this kind
> of bench and maybe document this case (spring boot could inherit from it
> since it almost never use anything else that default spring servlet and
> binds everything in it).
>
> Here is the kind of case I'd like to see insanely fast (<100ms - and it is
> possible regarding what it does):
>
> public class Main {
> public static void main(String[] args) throws LifecycleException,
> InterruptedException {
> final long start = System.nanoTime();
> Registry.disableRegistry();
> final long startDisableRegistry = System.nanoTime();
>
> final Host host = new StandardHost();
> host.setName("localhost");
> final long startHost = System.nanoTime();
>
> final Engine engine = new StandardEngine();
> engine.setName("Tomcat");
> engine.setDefaultHost("localhost");
> engine.setRealm(new NullRealm());
> engine.addChild(host);
> final long startEngine = System.nanoTime();
>
> final var protocolHandler = new Http11Nio2Protocol();
> protocolHandler.setPort(8080);
> final long startHttp11Nio2Protocol = System.nanoTime();
>
> final Service service = new StandardService();
> service.setName("Tomcat");
> service.setContainer(engine);
> service.addConnector(new Connector(protocolHandler));
> final long startService = System.nanoTime();
>
> final StandardServer server = new StandardServer();
> server.setPort(-1);
> server.addService(service);
> final long startServer = System.nanoTime();
>
> final StandardContext context = new StandardContext();
> context.setUseNaming(false);
> context.setClearReferencesStopThreads(false);
> context.setClearReferencesStopTimerThreads(false);
> context.setClearReferencesHttpClientKeepAliveThread(false);
> context.setClearReferencesRmiTargets(false);
> context.setClearReferencesThreadLocals(false);
> context.setClearReferencesObjectStreamClassCaches(false);
> context.setWorkDir(System.getProperty("java.io.tmpdir"));
> context.setName("");
> context.setPath("");
> context.setDocBase(null);
> context.addLifecycleListener(event -> {
> if (event.getType().equals(Lifecycle.CONFIGURE_START_EVENT)) {
> context.setConfigured(true);
> if (context.getLoginConfig() == null) {
> context.setLoginConfig(new LoginConfig("NONE", null,
> null, null));
> context.getPipeline().addValve(new
> NonLoginAuthenticator());
> }
> }
> });
> context.addServletContainerInitializer((classes, ctx) -> {
> ctx.addServlet("default", new DefaultServlet())
> .addMapping("/");
> }, Set.of());
> final long startContext = System.nanoTime();
>
> host.addChild(context);
>
> server.init();
> final long inited = System.nanoTime();
> server.start();
> final long started = System.nanoTime();
> // new CountDownLatch(1).await();
>
> final var contextClassLoader =
> Thread.currentThread().getContextClassLoader();
>
> server.stop();
> server.destroy();
> final long stopped = System.nanoTime();
>
> System.out.println(TimeUnit.NANOSECONDS.toMillis(started - start) +
> "ms");
> System.out.println(TimeUnit.NANOSECONDS.toMillis(stopped - started)
> + "ms");
> System.out.println();
> System.out.println("startDisableRegistry: " +
> TimeUnit.NANOSECONDS.toMillis(startDisableRegistry - start) + "ms");
> System.out.println("startHost: " +
> TimeUnit.NANOSECONDS.toMillis(startHost - startDisableRegistry) + "ms");
> System.out.println("startEngine: " +
> TimeUnit.NANOSECONDS.toMillis(startEngine - startHost) + "ms");
> System.out.println("startHttp11Nio2Protocol: " +
> TimeUnit.NANOSECONDS.toMillis(startHttp11Nio2Protocol - startEngine) +
> "ms");
> System.out.println("startService: " +
> TimeUnit.NANOSECONDS.toMillis(startService - startEngine) + "ms");
> System.out.println("startServer: " +
> TimeUnit.NANOSECONDS.toMillis(startServer - startService) + "ms");
> System.out.println("startContext: " +
> TimeUnit.NANOSECONDS.toMillis(startContext - startServer) + "ms");
> System.out.println("actualInit: " +
> TimeUnit.NANOSECONDS.toMillis(inited - startContext) + "ms");
> System.out.println("actualStart: " +
> TimeUnit.NANOSECONDS.toMillis(started - inited) + "ms");
> }
> }
>
>
> Current reference output (medium values) is - on java 11:
>
> 364ms
> 22ms
>
> startDisableRegistry: 58ms
> startHost: 19ms
> startEngine: 7ms
> startHttp11Nio2Protocol: 25ms
> startService: 39ms
> startServer: 12ms
> startContext: 26ms
> actualStart: 200ms
>
> Wdyt? Anyone had a look before?
>
It is not possible to disable JMX by default since in addition to the
obvious monitoring with visualvm or similar, it is also a building block
for a lot of other features in Tomcat (manager and status webapps, TLS
reload, storeconfig). It's a bit the same for JNDI.
Overall, AOT compilation is likely a better solution for the use case you
describe, that was the whole point of adding support for it.
Rémy
>
>
> PS: if curious the registry patch i did was:
> https://gist.github.com/rmannibucau/e7cb9674fa4a21ccfe9eb956b509fad1 -
> indeed since it does not help overall I don't ask to integrate it at all,
> just a FYI
>
> Romain Manni-Bucau
> @rmannibucau <https://twitter.com/rmannibucau> | Blog
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> <
> https://www.packtpub.com/application-development/java-ee-8-high-performance
> >
>
