Re: [PATCH 3/7] btrace: Use binary search to find instruction.

[Simon Marchi <simon dot marchi at polymtl dot ca>]

On 2016-10-27 02:28, Tim Wiederhake wrote:
> Currently, btrace_find_insn_by_number will iterate over all function 
> call
> segments to find the one that contains the needed instruction.  This 
> linear
> search is too slow for the upcoming Python bindings that will use this
> function to access instructions.  This patch introduces a vector in 
> struct
> btrace_thread_info that holds pointers to all recorded function 
> segments and
> allows to use binary search.
>
> The proper solution is to turn the underlying tree into a vector of 
> objects
> and use indices for access.  This requires more work.  A patch set is
> currently being worked on and will be published later.

Hi Tim,

Unless you expect to backport this patch in the 7.12 branch (which I 
don't think is the case here), you can use C++ standard containers and 
functions.  Specifically, std::vector instead of DEF_VEC, and probably 
std::lower_bound (if I understand correctly what the code is doing).

Also, since we now have btrace_function pointers in a sorted vector, do 
we still need them to be linked together as a linked list?

Simon