Here's something interesting. So the last method I had to write, StackTraceFrame.getStackTrace(Throwable), I finished last night. It's the alternative to Throwable.getStackTrace(). Instead of returning StackTraceElement[] (String for declaring class name), it returns StackTraceFrame[] (Class<?> for declaring class). I expected this to perform about the same or possibly even worse--boy was I wrong.
StackTraceFrame.getStackTrace(Throwable) consistently returns in half the time that Throwable.getStackTrace() does. Looking at why that is, I found a HUGE inefficiency in Throwable.getStackTrace(). StackTraceFrame.getStackTrace(Throwable) walks the backtrace 1 time and runs O(n), where n is the number of elements in the stack trace. Throwable.getStackTrace() walks the back trace 1+(n/2) times (first it measures the depth of the back trace in one native method call, then it gets the elements by index in a native method call for each, looping up to that index each time), for an O(nlogn) (I think) running time. Much worse. So ... I improved Throwable.getStackTrace() and cut its running time in half while I was at it. This also resulted in cutting Thread.currentThread().getStackTrace()'s runtime in half. Think they'll appreciate it? :-/ N On Jul 31, 2013, at 4:42 PM, Paul Benedict wrote: > http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-July/019486.html > > > On Wed, Jul 31, 2013 at 4:40 PM, Gary Gregory <garydgreg...@gmail.com> wrote: > Hm... do you have a URL for this ray of hope? > > Gary > > > On Wed, Jul 31, 2013 at 5:34 PM, Paul Benedict <pbened...@apache.org> wrote: > Nevermind. I just found it. Lousy browser caching! > > > On Wed, Jul 31, 2013 at 4:33 PM, Paul Benedict <pbened...@apache.org> wrote: > Did you find this out on the OpenJDK mailing list? I can't find the > information; I may have missed it. > > > On Wed, Jul 31, 2013 at 4:22 PM, Gary Gregory <garydgreg...@gmail.com> wrote: > KA-POW! Well done, sir. How about we use your mug as the new logo? ;) > > Gary > > > On Wed, Jul 31, 2013 at 4:47 PM, Nick Williams > <nicho...@nicholaswilliams.net> wrote: > A PARTIAL VICTORY! > > They've decide to revert the change to Reflection.getCallerClass for 7u40 and > the rest of 7. Woohoo! > > "What will happen to this method in JDK 8 requires further thought." > > Meanwhile, about 300 lines of Java and 1,000 lines of native code later, I'm > about ready to submit my patch for a public API replacement in Java 8. > > N > > On Jul 29, 2013, at 8:39 AM, Gary Gregory wrote: > >> What a mess :( it seem unlikely new APIs will be added to Java 8 to help us, >> at least based on comments like >> http://mail.openjdk.java.net/pipermail/core-libs-dev/2013-July/019110.html >> >> We might be left with documenting our side with "if you use features x and y >> in this context then the speed will degrade to so and so, here is where to >> ask Oracle to fix it: http:..." >> >> Gary >> >> On Jul 29, 2013, at 9:06, Nick Williams <nicho...@nicholaswilliams.net> >> wrote: >> >>> core-libs-dev > > > > > -- > E-Mail: garydgreg...@gmail.com | ggreg...@apache.org > Java Persistence with Hibernate, Second Edition > JUnit in Action, Second Edition > Spring Batch in Action > Blog: http://garygregory.wordpress.com > Home: http://garygregory.com/ > Tweet! http://twitter.com/GaryGregory > > > > -- > Cheers, > Paul > > > > -- > Cheers, > Paul > > > > -- > E-Mail: garydgreg...@gmail.com | ggreg...@apache.org > Java Persistence with Hibernate, Second Edition > JUnit in Action, Second Edition > Spring Batch in Action > Blog: http://garygregory.wordpress.com > Home: http://garygregory.com/ > Tweet! http://twitter.com/GaryGregory > > > > -- > Cheers, > Paul
