I, too, would like someone from the Jetty team to answer this. Perhaps there is a page describing Jetty's thread management?
On Fri, May 2, 2014 at 6:51 AM, Roland Dragoi <[email protected]>wrote: > Hi, > > I am using the embedded Jetty web server (9.13), for which I configure the > maximum number of threads in the thread pool (maxThreads). > By looking into the Jetty code, I noticed that Jetty uses a formula for > determining the minimum allowed value for maxThreads = 1 + noConnectors*(1 > + noCores/16 + noCores). > That is, for every configured connector, Jetty allocates a number of 1 + > noCores/16 acceptor threads and a number of noCores selector threads. > My problem is that if I use a value for the maxThread property close to > the minimum accepted by Jetty, the browser blocks when loading the page. > By monitoring my application on a machine with 80 cores, I noticed that in > the Jetty thread pool there are 6 acceptor threads (of which only one is > running at any given time) and 80 selector threads (all of them are running > continuously in the selector loop). If I configure the maxThreads to the > minimum accepted of 87, I am only left with 1 thread to actually do the > work of handling the request and the browser blocks, as many requests stay > pending. Of course, I could just increase the maxThreads value until it > works, but the memory resources are limited. In my case I only use one > connector, but if I will later add a second connector for HTTPS, the number > of selector threads will double. Also, Jetty uses by default a number of > 200 for the maxThreads property, but I imagine that on a machine with even > more cores, my problem will become the default. > I noticed it is possible to also configure the number of acceptors and > selectors for each connector and I intend to try that, but I would like to > understand first what they do. > > *My question for you is what is exactly that the selector threads do and > if such a great number of them is really necessary. * > *If I were to decrease their number, is there a recommended ratio between > the selector threads and the worker threads? * > > Thank you for any pointers in this matters! > > Roland > > _______________________________________________ > jetty-users mailing list > [email protected] > https://dev.eclipse.org/mailman/listinfo/jetty-users > >
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