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[Bug dynamic-link/15310] _dl_sort_fini is O(n^3) causing slow exit when many dsos
- From: "law at redhat dot com" <sourceware-bugzilla at sourceware dot org>
- To: glibc-bugs at sourceware dot org
- Date: Wed, 27 Mar 2013 21:13:39 +0000
- Subject: [Bug dynamic-link/15310] _dl_sort_fini is O(n^3) causing slow exit when many dsos
- Auto-submitted: auto-generated
- References: <bug-15310-131 at http dot sourceware dot org/bugzilla/>
http://sourceware.org/bugzilla/show_bug.cgi?id=15310
--- Comment #7 from law at redhat dot com 2013-03-27 21:13:39 UTC ---
Carlos,
This is the tester QE uses for the correctness of the sort:
Basically it takes as an input the number of DSOs you want to test. Then
builds a random orderings and a pathological ordering of those DSOs on the link
line (the script knows the dependencies between DSOs).
deps.cpp:
#include <stdio.h>
#ifdef MAIN
int
main( int argc, char *argv[] )
{
printf("main\n");
}
#else
static bool deps_init( void ) { puts( NAME ); }
bool x = deps_init();
#endif
driver:
#!/bin/bash
# based on reproducer from bug 11724
N=${1:-2}
TmpDir=$(mktemp -d)
cp deps.cpp $TmpDir
pushd $TmpDir > /dev/null 2>&1
for((all=0,k=2; k<=$N; ++all,++k)); do
cmd="g++ -fPIC -shared -o libdeps${k}.so -DNAME=\\\"${k}\\\" deps.cpp"
printf "# %s\n" "$cmd" > ${all}r.log
eval "$cmd"
for ((i=k-1; i>=1; --i)); do
cmd="g++ -L. -fPIC -shared -o libdeps${i}.so -ldeps$((i+1))
-DNAME=\\\"${i}\\\" deps.cpp"
printf "# %s\n" "$cmd" >> ${all}r.log
eval "$cmd"
done; unset i
# random link order
# it sucks that rhel5 coreutils don't have shuf or sort -R yet :)
roptions=($(seq 1 $k | sed 's/^/ -ldeps/'))
for ((i=(${#roptions[@]}-1); i >= 1; --i)); do
random=$((RANDOM % i))
m=${roptions[$random]}
roptions[$random]=${roptions[$i]}
roptions[$i]=$m
done; unset i
rcmd="g++ -Wl,-rpath -Wl,$(pwd) -L. -o rmain ${roptions[@]} -DMAIN
deps.cpp"
# pathological link order
poptions=($(seq $k -1 1 | sed 's/^/ -ldeps/'))
pcmd="g++ -Wl,-rpath -Wl,$(pwd) -L. -o pmain ${poptions[@]} -DMAIN
deps.cpp"
cp ${all}r.log ${all}p.log
for i in r p; do
cmd="${i}cmd"
printf "# %s\n\n" "${!cmd}" >> ${all}${i}.log
eval "${!cmd}"
fail=0
cp ${all}${i}.log ${i}out.golden
./${i}main >> ${all}${i}.log
seq $k -1 1 >> ${i}out.golden
echo main >> ${i}out.golden
diff ${all}${i}.log ${i}out.golden > /dev/null 2>&1 || fail=1
# it's ok, we don't care
if [ 0 -eq $fail ]; then
rm ${all}${i}.log
fi
done; unset i
rm -rf *.so *main *out.golden *out.real
done; unset k
rm deps.cpp
test 0 -eq $(ls | wc -l) && { rm -rf $(pwd); echo PASS; } || { echo FAIL;
printf "results are in %s\n" $(pwd); }
popd > /dev/null 2>&1
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