[llvm-dev] 7-8% compile time slowdowns in LLVM 10
David Chisnall via llvm-dev
llvm-dev at lists.llvm.org
Thu Apr 16 05:39:04 PDT 2020
On 15/04/2020 18:32, Alexandre Ganea via llvm-dev wrote:
> I suggested Neil to apply https://reviews.llvm.org/D71786 (rpmalloc) and
> he reported:
> “[..] its about 6.5% faster using the rpmalloc LLVM vs LLVM 9 without.
> It is a cool 14% faster than LLVM 10 too!”
> I ran some tests locally, and as a first order of approximation, /even
> without rpmalloc/ it seems Clang 10 is faster than Clang 9 for a whole
> build. Although locally when iterating on a single file, it could be
> slower like Neil suggests.
FWIW: I'm running locally with snmalloc replacing jemalloc as the
default FreeBSD allocator and clang is about 2% faster in some very
ad-hoc and informal testing. Over SPEC on Windows I think (from memory,
testing was a while ago) we see around a 30% speedup of snmalloc vs the
Windows allocator (which has a lot of security features not present in
snmalloc). We've increased the performance of snmalloc since we last
did a SPEC run, malloc is now 14 instructions with no atomic operations
in the common case.
More information about the llvm-dev