Re: [gentoo-dev] New project: LLVM

["C Bergström" <cbergstrom@pathscale.com>]

I finally got it to build and here's the size numbers
952K    ./lib/libc++abi.a
616K    ./lib/libc++abi.so.1.0

If the above isn't enough motivation and you really want benchmarks
which prove it's a pig... I'll try to figure something else

Not exactly a 1:1 comparison because I think other things are mixed in, but...
352K    /usr/lib/gcc/x86_64-linux-gnu/4.9/libsupc++.a
356K    /usr/lib/gcc/x86_64-linux-gnu/5/libsupc++.a

In the land of HPC we frequently statically link stuff... not that
864KB is big by any sort of modern definition, but it does raise
questions..


On Sat, Aug 20, 2016 at 12:54 AM, Lei Zhang <zhanglei.april@gmail.com> wrote:
> 2016-08-19 11:11 GMT+08:00 C Bergström <cbergstrom@pathscale.com>:
>> I think you're getting a bit confused
>>
>> libsupc++ is the default now, from GNU
>>
>> libcxxabi is the bloated runtime from Apple
>>
>> libcxxrt is the faster c++ runtime, PathScale+David Chisnall, which
>> PathScale and FreeBSD use by default. We don't need a version number
>> because it's pretty much rock solid stable for a while.
>> I'd encourage you to consider libcxxrt for at least the code size and
>> performance reasons. Build it and you'll see. Locally my unoptimized
>> libcxxrt.so is like 88K. How much is your libcxxabi (static and
>> shared)
>>
>> 88K    /opt/enzo-2016-06-26/lib/6.0.983/x8664/64/libcxxrt.so
>> 140K    /opt/enzo-2016-06-26/lib/6.0.983/x8664/64/libcxxrt.a
>> // This seems larger than I remember and I need to check why.
>>
>> https://github.com/pathscale/libcxxrt
>
> Currently libcxxrt is the default ABI lib for libc++ in Gentoo. I mean
> to replace it with libc++abi in that context.
>
> I'm interested in benchmarking to reveal the claimed difference in
> performance. Perhaps I can build the same program against libcxxrt and
> libc++abi respectively and see how it behaves. Do you have some hints
> on what kind of programs I should test?
>
>
> Thanks,
> Lei
>