On 25/03/2019 08:40, Thibault Kruse wrote: > On Wed, Mar 20, 2019 at 7:04 PM Mark Thomas <ma...@apache.org> wrote: >> >> On 20/03/2019 05:13, Thibault Kruse wrote: >>> Hi, >>> >>> when migrating from Tomcat7 to Tomcat8 for an application using javax-el >>> expression evaluation on every request, we noticed a significant >>> performance impact. >> >> Try the latest 8.5.x implementation. > > It is the same issue with > * org.apache.tomcat:tomcat-jasper-el:8.5.38 > * org.apache.tomcat:tomcat-jasper-el:8.5.39 > * org.apache.tomcat:tomcat-jasper-el:9.0.14.1 > >> If you still see an issue, a simple test case that reproduces the issue >> would be appreciated. > > This example project demonstrates the issue with a naive benchmark (I > know JMH would be better): > https://github.com/tkruse/javax-getvalue-slowdown
Thanks. That helps clarify the situation. I can see the difference (a factor of between 3 and 4) running that code with Tomcat 7.0.x and 9.0.x. I'll have a look with a profiler. I will note at this point that the work-around commented out in that test case is not specification compliant. For example, null coerced to String should result in "". Mark > > In > https://github.com/tkruse/javax-getvalue-slowdown/blob/dd4fbab443c31ccf4f791bb8b873cfcb3ebefc1b/src/test/java/javax/el/demo/BenchmarkEl.java#L73 > it is possible to bypass the unnecessary code (unnecessary for our > use-case and likely many other use-cases), and reduce the slowdown > somewhat. We can also try adding a custom ELResolver to the > CompositeELResolver which handles the simple coercion cases, though > that seems a bit more complex since class ELResolver has a lot of > methods to implement. > > But ideally we want to keep having apache-el:7 performance, and we > currently consider shading apache-el:7 to run our code on Tomcat8 with > shaded apache-el:7 as additional library on the classpath. If there > was a better way to avoid the performance hit (without using all > JavaEE7 language features), that would be useful to know. > > >> Finally, note that org.mortbay.jasper:apache-el:8.0.33 is not something >> that has been released by the Tomcat project. > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > --------------------------------------------------------------------- To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org For additional commands, e-mail: users-h...@tomcat.apache.org
