[llvm-dev] [Mesa-dev] issues with split llvm libraries and llvmpipe and failing to load library

Michel Dänzer via llvm-dev llvm-dev at lists.llvm.org
Thu Feb 11 23:57:09 PST 2016

On 12.02.2016 00:05, Nicolai Hähnle wrote:
> On 10.02.2016 22:59, Dave Airlie wrote:
>> So in Fedora rawhide we are now building llvm 3.7.1 into the lots of
>> little shared libraries format.
> Barring all the other problems, are you sure this is a good idea? I
> remember somebody mentioning that at least LLVM's own test suite runs
> much slower in this build configuration.

I didn't measure the LLVM testsuite wrt this, but I did measure that the
split shared libraries increase the runtime of a single piglit test by
about 0.02s, which for a full piglit run adds up to about 400 CPU core
seconds, i.e. about 6.667 CPU core minutes.

> I don't know whether this is "only" due to a slower startup time in
> the dynamic linker or also due to slower compile times at runtime, but
> it's probably worth measuring.

I didn't investigate it in detail, but I assume it's the former. I don't
know of any other significant difference between the two cases I measured.

Earthling Michel Dänzer               |               http://www.amd.com
Libre software enthusiast             |             Mesa and X developer

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