Hi, Repeatable benchmarks showing a significant improvement for some use case would be appreciated (certainly) and a prerequisite (probably) for addition into this relatively core part of Tomcat. I don't think this is much different than setting the current maxThreads (and min/max Spare threads) as opposed to acceptCount: one could set maxThreads to 20 and acceptCount to 500, for example.
Yoav Shapira System Design and Management Fellow MIT Sloan School of Management / School of Engineering Cambridge, MA USA [EMAIL PROTECTED] / [EMAIL PROTECTED] > -----Original Message----- > From: Scott Marlow [mailto:[EMAIL PROTECTED] > Sent: Wednesday, May 04, 2005 9:42 AM > To: tomcat-dev@jakarta.apache.org > Cc: [EMAIL PROTECTED] > Subject: Tomcat performance patch (in development) to reduce concurrency... > > Hi, > > I wonder if anyone has any feedback on a performance change that I am > working on making. > > One benefit of reducing concurrency in a server application is that a > small number of requests can complete more quickly than if they had to > compete against a large number of running threads for object locks (Java > or externally in a database). > > I would like have a Tomcat configuration option to set the max number of > concurrent threads that can service user requests. You might configure > Tomcat to handle 800 http client connections but set the max concurrent > requests to 20 (perhaps higher if you have more CPUs). I like to refer > to the max concurrent requests setting as the throttle size (if there is > a better term, let me know). > > I modified the Tomcat Thread.run code to use Doug Lea's semaphore > support but didn't expose a configuration option (haven't learned how to > do that yet). My basic change is to allow users to specify the max > number of concurrent servlet requests that can run. If an application > has a high level of concurrency, end users may get more consistent > response time with this change. If an application has a low level of > concurrency, my change doesn't help as their application only has a few > threads running concurrently anyway. > > This also reduces resource use on other tiers. For example, if you are > supporting 500 users with a Tomcat instance, you don't need a database > connection pool size of 500, instead set the throttle size to 20 and > create a database connection pool size of 20. > > Current status of the change: > > 1. org.apache.tomcat.util.threads.ThreadPool.CONCURRENT_THREADS is > hardcoded to a value of 18, should be a configurable option. > 2. I hacked the build scripts to include Doug Lea's concurrent.jar but > probably didn't make these changes correctly. I could switch to using > the Java 1.5 implementation of the Concurrent package but we would still > need to do something for Java 1.4 compatibility. > > Any suggestions on completing this enhancement are appreciated. > > Please include my [EMAIL PROTECTED] email address in your response. > > Thank you, > Scott Marlow --- Tomcat newbie --------------------------------------------------------------------- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
