Date: Sun, 26 Aug 2012 02:00:31 +0200 From: musl <b.brezillon.musl@...il.com> To: musl@...ts.openwall.com 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? I tried the perf application ( https://perf.wiki.kernel.org/index.php/Tutorial <https://perf.wiki.kernel.org/index.php/Tutorial#Counting_with_perf_stat>) with this command : 'perf stat -e instructions:u ./gnuhash main' (gives number of instructions executed in user space by gnuhash program). Here are the results : With bloom filter : 577 0x80483c4 Performance counter stats for './gnuhash main': 31 895 instructions:u # 0,00 insns per cycle 0,000792737 seconds time elapsed Without bloom filter : 588 0x80483c4 Performance counter stats for './gnuhash main': 31 195 instructions:u # 0,00 insns per cycle 0,000802368 seconds time elapsed As you can see there are less instructions executed in the version without bloom filter but it's slower. I guess this difference come from the symbol resolution during the relocation process. > 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. > > Rich Content of type "text/html" skipped
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