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Date: Sun, 26 Aug 2012 00:13:58 +0200
From: musl <>
Subject: Re: ldso : dladdr support

On 24/08/2012 20:38, Rich Felker wrote:
> On Fri, Aug 24, 2012 at 09:29:29AM +0200, musl wrote:
>> I tested it and it works well.
> Is there anything I changed that you think might be better done a
> different way?
>> My tests are based on small libs (with a small set of shared symbols).
>> I mixed libs with gnu hash and sysv hash.
>> Tried to resolve symbols via dlsym.
>> Have you tested it on big libraries ?
> No, just very minimal testing.
>> Do you want me to do some specific tests ?
> Actually, the main thing I'm interested in is whether the bloom filter
> is ever beneficial. I took it out trying to streamline the code and
> shaved about 8% off the lookup time for symbols in the main program,
> but I didn't investigate how the change affects symbols not found in
> the first file searched. Would you be interested in running some tests
> to determine if it might be useful to try adding it back?
> Since it seems to be working/non-broken right now, I'll probably go
> ahead and commit soon unless you find a major problem I've overlooked.
> Then we can work on improving it once it's in the repo.
I executed your test program (gnuhash) with and without bloom filter test, and I get pretty much the same results in
both cases if the symbol is defined.
What compiler option did you use to compile gnuhash.c ?

I also tried to search for a missing symbol and the version with bloom filter is 3% faster.

I'll do more tests with bigger libs and different linker optimizations (some linker optims change the number of buckets
in the hash table => less entries per hash chains => faster search in case there's no valid entry for a given name).


> Rich

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