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<div dir="ltr">Sorry for missing that, it's one (randomly selected) STL #include <vector> with an empty main function as below:
<div>$ perf stat -a -- clang++ -o /dev/null --compile -std=c++11 <a href="http://test.cc">test.cc</a></div>
<div><br>
</div>
<div> Performance counter stats for 'system wide':</div>
<div><br>
</div>
<div> 6286.898000 cpu-clock (msec) # 7.984 CPUs utilized</div>
<div> 1,029 context-switches # 0.164 K/sec</div>
<div> 23 cpu-migrations # 0.004 K/sec</div>
<div> 5,069 page-faults # 0.806 K/sec</div>
<div> 3,359,820,123 cycles # 0.534 GHz</div>
<div> 3,011,112,580 instructions # 0.90 insn per cycle</div>
<div> 565,470,025 branches # 89.944 M/sec</div>
<div> 3,667,572 branch-misses # 0.65% of all branches</div>
<div><br>
</div>
<div> 0.787455804 seconds time elapsed</div>
<div><br>
</div>
<div>$ perf stat -a -- clang++ -o /dev/null --compile -std=c++11 -stdlib=libc++ <a href="http://test.cc">
test.cc</a></div>
<div><br>
</div>
<div> Performance counter stats for 'system wide':</div>
<div><br>
</div>
<div> 20095.100787 cpu-clock (msec) # 7.995 CPUs utilized</div>
<div> 1,128 context-switches # 0.056 K/sec</div>
<div> 44 cpu-migrations # 0.002 K/sec</div>
<div> 7,716 page-faults # 0.384 K/sec</div>
<div> 11,861,997,273 cycles # 0.590 GHz</div>
<div> 10,930,520,024 instructions # 0.92 insn per cycle</div>
<div> 2,064,359,090 branches # 102.729 M/sec</div>
<div> 10,959,608 branch-misses # 0.53% of all branches</div>
<div><br>
</div>
<div> 2.513417717 seconds time elapsed</div>
<div><br>
</div>
<div>$ clang++ -o libstdcxx.o -std=c++11 <a href="http://test.cc">test.cc</a></div>
<div>$ clang++ -o libcxx.o -std=c++11 -stdlib=libc++ <a href="http://test.cc">test.cc</a></div>
<div><br>
</div>
<div>$ ldd libstdcxx.o</div>
<div> linux-vdso.so.1 (0x00007fff3efc7000)</div>
<div> libstdc++.so.6 => /home/yiyan/.local/lib64/libstdc++.so.6 (0x00007fb320d6f000)</div>
<div> libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007fb3209d1000)</div>
<div> libgcc_s.so.1 => /home/yiyan/.local/lib64/libgcc_s.so.1 (0x00007fb3207b9000)</div>
<div> libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007fb3203c8000)</div>
<div> /lib64/ld-linux-x86-64.so.2 (0x00007fb32114e000)</div>
<div><br>
</div>
<div>$ ldd libcxx.o</div>
<div> linux-vdso.so.1 (0x00007fffd8fe4000)</div>
<div> libc++.so.1 => /home/yiyan/.local/lib/libc++.so.1 (0x00007f01bbcba000)</div>
<div> libc++abi.so.1 => /home/yiyan/.local/lib/libc++abi.so.1 (0x00007f01bba65000)</div>
<div> libm.so.6 => /lib/x86_64-linux-gnu/libm.so.6 (0x00007f01bb6c7000)</div>
<div> libgcc_s.so.1 => /home/yiyan/.local/lib64/libgcc_s.so.1 (0x00007f01bb4af000)</div>
<div> libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f01bb0be000)</div>
<div> libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f01bae9f000)</div>
<div> librt.so.1 => /lib/x86_64-linux-gnu/librt.so.1 (0x00007f01bac97000)</div>
<div> /lib64/ld-linux-x86-64.so.2 (0x00007f01bbfc8000)</div>
<div><br>
</div>
<div>$ cat <a href="http://test.cc">test.cc</a></div>
<div>#include <vector></div>
<div><br>
</div>
<div>int main() {}</div>
<br>
<div dir="ltr">Yichen</div>
<div dir="ltr"><br>
On Aug 25, 2019, at 10:47 PM, Eric Fiselier <<a href="mailto:eric@efcs.ca">eric@efcs.ca</a>> wrote:<br>
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<blockquote type="cite">
<div dir="ltr">
<div dir="ltr">You would need to tell us what you're actually compiling before we can guess at the problem.
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<div>/Eric</div>
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<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Sat, Aug 24, 2019 at 2:28 PM Yan Yichen via libcxx-dev <<a href="mailto:libcxx-dev@lists.llvm.org">libcxx-dev@lists.llvm.org</a>> wrote:<br>
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<blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div lang="DE-CH">
<div class="gmail-m_7062386912846246979WordSection1">
<p class="MsoNormal"><span lang="EN-US">Dear developers,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"> Sorry to bother you, but I’ve met a wired problem using clang with libcxx.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"> I’ve built clang and libcxx with clang, and trying to compile c++ program with libc++, but compilation is extremely slow when using libcxx, as below:<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">$ time clang++ -o /dev/null -std=c++11 -stdlib=libc++
<a href="http://test.cc">test.cc</a><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">clang++ -o /dev/null -std=c++11 -stdlib=libc++
<a href="http://test.cc">test.cc</a> 4.29s user 0.06s system 97% cpu 4.476 total<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">$ time clang++ -o /dev/null -std=c++11 <a href="http://test.cc">
test.cc</a><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">clang++ -o /dev/null -std=c++11 <a href="http://test.cc">
test.cc</a> 1.41s user 0.06s system 92% cpu 1.582 total<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"> I wonder if you have any idea where should I start to address this issue, or anything I probably configured wrong? Thanks in advanced.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Best,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US">Yichen<u></u><u></u></span></p>
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