Re: maxThreads
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Pid, On 4/1/2011 6:43 AM, Pid wrote: > On 01/04/2011 06:58, Kaushal Shriyan wrote: >> Hi, >> >> What are the implications or issues if maxThreads are increased from the >> default 150 to 300 threads. Are there any performance issues ? > > Yes, may be at risk of improving performance. Hah. Seriously, to the OP: if your webapp under load is not really using the CPU or network much (that is, you're waiting on some other resource) and still taking a long time to service requests, then increasing the number of connections is likely to /slow your webapp down/ because you will be putting more strain on those already-taxed resources. On the other hand, if your webapp under load is using a lot of CPU time, then you will also experience a slowdown because you'll end up with more context switches to service all those requests PLUS you'll have more load on the CPU doing actual work. Finally, increasing the maxThreads will increase your memory requirements for two reasons: first, you'll need a stack for each thread to use (see your JVM's default or command-line switches for what that per-thread memory requirement is) PLUS you'll need the amount of memory that a typical request (or particularly memory-heavy request, if you want to be really safe) will use FOR EACH THREAD. The best thing to do is to load test your webapp and see what point your webapp stops responding in a reasonable amount of time (to be determined by your own requirements). If your response time is very fast and your server is using very little CPU, then you can increase the maxThreads until things start to become intolerable. Oh, and if you are using Tomcat behind some web server like Apache httpd, you might want to make sure that your value for maxThreads matches whatever configuration you have on the web server so that you can actually serve that many requests through to Tomcat. ;) - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.10 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk2V6rAACgkQ9CaO5/Lv0PCNYQCfUQ+KKMvNUbbsgI2jQ8DgfeoF 90EAoMKOwBIwrcsuv8LZsC5sRkXajcj/ =JaTv -END PGP SIGNATURE- - To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
Re: maxThreads
On 01/04/2011 06:58, Kaushal Shriyan wrote: > Hi, > > What are the implications or issues if maxThreads are increased from the > default 150 to 300 threads. Are there any performance issues ? Yes, may be at risk of improving performance. p > I am using TC 5.5.27 , Ubuntu Linux Server 8.04 , Sun Java 1.6.0 Update 24 > > Please suggest/guide. > > Thanks and Regards, > > Kaushal > signature.asc Description: OpenPGP digital signature
Re: MaxThreads <-> max. users ?
Like most things in complex network apps there is no simple answer. MaxThreads refers to the number of simultaneous open HTTP network connections there can be. A connection is opened to enable the HTTP request response cycle (request from browser -> server, response from server-> browsers). This does not exactly translate into users because depending upon the page it is possible for the browser to make multiple simultaneous requests (images, text, javascript, css etc) for the same browser page. 'Sessions' in web server parlance refers to the ability whereby the server can track the state of a 'user conversation' which may spread across many pages. The identification of the user must be saved throughout this session if there are authentication issues involved - private pages, secure forms etc. There is no direct relationship between the number of sessions and the number of active, open connections. When estimating the capacity of a server you must work out the average page response time and then that will give you the number of users/hour. The only real way that you can really determine the performance of a server is to measure it - there are simply too many interacations at a system level to make sense of any simple calculations. A server set to handle 200 max connections with a response time of 200ms can probably handle around about 1000 connections a second. Factors to consider: 1. what kind of application? Simple file access or complex database? 2. the need for failover (clustering etc) 3. what kind of user interaction? (forms, simple page browsing?) It should be noted that client interactions using 'ajax' techniques where the browser reconnects mid-page can actually cause a significant increase in server traffic. Once again, the only way to know is to experiment. HTH Alan Chaney Stephanie Wullbieter wrote: Hello, on http://tomcat.apache.org/tomcat-5.5-doc/config/http.html is for parameter MaxThreads written: "The maximum number of request processing threads to be created by this Connector, which therefore determines the maximum number of simultaneous requests that can be handled. If not specified, this attribute is set to 200." Could You please tell me what exact a "request" is? Does it mean that when I have e.g. MaxThreads=20, 100 users can use my webapp if only 20 of them at the same time request data from the webapp and the others drink coffee? Is it the same when i have session based sso login? Thank You kindly - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
RE: MaxThreads <-> max. users ?
> From: Stephanie Wullbieter [mailto:[EMAIL PROTECTED] > Subject: MaxThreads <-> max. users ? > > Could You please tell me what exact a "request" is? An HTTP GET, POST, etc., request from a client (usually a browser). Note that retrieval of a single web page may result in many separate requests from the client to load images, CSS files, scripts, etc. > Does it mean that when I have e.g. MaxThreads=20, 100 users > can use my webapp if only 20 of them at the same time request > data from the webapp and the others drink coffee? Yes, with restrictions. If the client maintains a keep-alive request and you're using the standard connector, a thread will be tied up for the duration. If you use the NIO or APR connectors, the thread will be released back to the pool in the keep-alive situation. Take a look at the table at the bottom of this page: http://tomcat.apache.org/tomcat-6.0-doc/config/http.html#Connector%20Com parison > Is it the same when i have session based sso login? Yes; they're independent mechanisms. - Chuck THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers. - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: MaxThreads <-> max. users ?
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 Stephanie, Stephanie Wullbieter wrote: | Could You please tell me what exact a "request" is? | | Does it mean that when I have e.g. MaxThreads=20, 100 users can use | my webapp if only 20 of them at the same time request data from the | webapp and the others drink coffee? Exactly. A request is when the client makes a connection to the web server and issues an HTTP request (like GET /index.html). While that request is being processes (typically a very short amount of time), one of the threads configured above is busy handling the request. After the request has been handled, the thread goes back to sleep to wait for another request to come on. | Is it the same when i have session based sso login? Sessions, SSO, etc. do not affect this behavior. - -chris -BEGIN PGP SIGNATURE- Version: GnuPG v1.4.9 (MingW32) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org iEYEARECAAYFAkgYkMsACgkQ9CaO5/Lv0PB3YgCeIkDlB6pswhNQpWbP8XzDkGRn glwAn1woJafGRd7PHgqglBj5+xiz3Quv =yzZP -END PGP SIGNATURE- - To start a new topic, e-mail: users@tomcat.apache.org To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
Re: maxThreads compared to maxProcessors
"Sean O'Reilly" <[EMAIL PROTECTED]> wrote in message news:[EMAIL PROTECTED] >I am using maxThreads in my ajp connector configuration in tomcat-5.0.28 > but looking at the documentation it says i should be using > maxProcessors. Is this the case ? > I believe that on 5.0.x, maxProcessors is an alias for maxThreads (but I don't care enough to look :). The maxThreads attribute will work however. On 5.5.x, the documentation is wrong: The maxProcessors attribute isn't simply deprecated, it is ignored. > -- > Sean O'Reilly > Systems Administrator > SECPay Ltd > > http://www.secpay.com > > [EMAIL PROTECTED] > > Mobile 07917 463906 > > DDI 01732 300212 > > This email contains information which is confidential. It is for the > exclusive use of the addressee(s). If you are not the addressee, please > note that any distribution, dissemination, copying or use of this > communication or the information in it is prohibited. If you have > received this email in error, please telephone me immediately. - To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
