[antlr-interest] c++ antlr profiling question
Brian Smith
brianlsmith at gmail.com
Tue Jun 14 14:53:25 PDT 2005
Those look like internal exception handling functions from GCC to me.
Perhaps you have some predicates that cause backtracking very often? I
believe that backtracking is implemented via ANTLR 2.x via exceptions,
and exceptions handling in GCC is designed to be fast when exceptions
_are not_ thrown, at the expense of being very expensive when they
_are_ through.
- Brian
On 6/14/05, Bryan Ewbank <ewbank at gmail.com> wrote:
> Hi Folks,
>
> We've been collecting some performance numbers, and I need help
> understanding them in the context of antlr.
>
> Any idea what these functions are (linux g++ compiler):
>
> % function name
> ----- ------------------------------
> 19.50 read_encoded_value_with_base(u
> 18.74 read_uleb128(unsigned char con
> 9.85 __gxx_personality_v0
> 6.75 base_of_encoded_value(unsigned
> 4.23 execute_cfa_program
> 4.03 _Unwind_IteratePhdrCallback
>
> Any information, especially on read_encoded_value_with_base, would be
> great. I see a few hits on the web, but nothing substantial. Having
> 20% of our execution time go into something that we don't grok
> concerns me a bit ;-)
>
More information about the antlr-interest
mailing list