debug in hotspot

[Xin Tong]

On Thu, May 3, 2012 at 8:29 PM, Krystal Mok <rednaxelafx at gmail.com> wrote:
> On 2012-5-4, at 8:16, Xin Tong <xerox.time.tech at gmail.com> wrote:
>
>> i would like to know how to debug in hotspot, what are some of the
>> standard procedures ? Lets say, the hotspot fails to run a Java
>> program. a few steps to triage the problem.
>>
>> 1. disable JIT compilers. hotspot has 2 compilers c1 and c2. they are
>> both used if TieredCompilation is enabled. How do I disable both of
>> them.
>
> It's there in the globals.hpp file: -XX:-UseCompiler
>
>> 2. if the Java program passes after the JIT is disabled. There is a
>> good chance that the problem is cause by the JIT. I want to narrow
>> down to a specific method, I can use PrintCompilation to find out all
>> the method compiled, but how can I disable one specific method from
>> being compiled.
>
> -XX:CompileCommand='exclude,your/class,yourMethod'
> Or an equivalent .hotspot_compiler configuration file.
> Read this thread for example (in Chinese): http://hllvm.group.iteye.com/group/topic/28201
>
>> 3. if i am able to limit down to a specific method, i want to start
>> disabling optimizations, is there an option to disable all
>> optimizations in the c1 and c2 compilers, or i need to do it manually
>> ?
>>
>
> I don't think there's an all-in-one flag to turn all optimizations off. At least not for now.
> See c1_globals.hpp and c2_globals.hpp to get an idea of what optimizations you can turn off.
>
> - Kris
>
>> Thanks

Thank you very much Kris. This is very helpful.