Re: [Libunwind-devel] interval based cache?

[Milian Wolff]

On Mittwoch, 12. April 2017 00:24:21 CEST Doug Moore wrote:
> The libunwind cache is based on hashing an instruction pointer (IP) value. 
> On a cache miss, the exploration for the right stack-popping info may come
> down to a search of intervals defined by an eh_frame_hdr, so that the
> interval found to include this IP could also include lots of neighboring
> instructions, which would also lead to cache misses, if we ever looked them
> up.  I’m wondering whether it's worth considering a change to the caching
> mechanism so that instead of using a hash table, it used some ordered data
> structure (binary tree, skip list, etc) of intervals, not IPs, so that
> there would be at most one cache miss per interval.
> 
> Is there a problem in my thinking here?  If not, is the libunwind world
> generally friendly or hostile to such a change?

From a user POV, this sounds interesting and quickly thinking about it I can't 
directly find an issue with it. If you have a patch available, I'm willing to 
test it and compare its performance impact to the baseline.

Cheers

-- 
Milian Wolff
address@hidden
http://milianw.de

signature.asc
Description: This is a digitally signed message part.