Also useful might be: --trace-deopt which prints a (very verbose) message when we jump from optimized code back into non-optimized code due to an invalid assumption that we made --trace-inlining which shows when a small function was attempted to be inlined into another function --trace-bailout which shows we stop with the optimizing compiler because we found a syntactic construct that we do not (currently) handle in optimized code
We'd be interested in knowing about code that deopts all the time when you think it shouldn't, or things you think we should be able to optimize but we bailout instead. Feel free to post here with questions if you don't understand the ouput. Keep in mind that all the tracing output is intended for the V8 developers working on the compiler and was not built as an optimization tool. Also keep in mind that version 3.0 is changing rapidly. On Thu, Dec 9, 2010 at 7:38 AM, Kasper Lund <[email protected]> wrote: > One flag that might be of interest to you is --trace-opt which dumps > information about optimizations being attempted. There are other new > trace flags -- take a look at > http://code.google.com/p/v8/source/browse/trunk/src/flag-definitions.h. > > Enjoy, > Kasper > > On Thu, Dec 9, 2010 at 2:57 AM, Yehuda Katz <[email protected]> wrote: > > Are there flags in V8 that will print out information about the V8 > > optimization process. For instance, in Hotspot, I can ask Java to > > print out debugging information when a method gets compiled (-XX: > > +PrintCompilation +PrintAssembly +PrintInlining) to see what kinds of > > optimizations are happening. > > > > This can be used to find trouble spots in code, where Hotspot is > > intentionally not optimizing something that you might expect to get > > optimized. One example would be methods that are too large to get > > compiled in Hotspot. Are there similar or equivalent mechanisms in v8. > > I am interested in learning more about what optimizations are > > performed on different kinds of code in more detail. > > > > Thanks, > > > > -- Yehuda Katz > > -- SproutCore > > -- Strobe, Inc. > > > > -- > > v8-users mailing list > > [email protected] > > http://groups.google.com/group/v8-users > > > > -- > v8-users mailing list > [email protected] > http://groups.google.com/group/v8-users > -- v8-users mailing list [email protected] http://groups.google.com/group/v8-users
