[ThinLTO] Default backend threads to heavyweight_hardware_concurrency
Summary:
Changes default backend parallelism from thread::hardware_concurrency to
the new llvm::heavyweight_hardware_concurrency, which for X86 Linux
defaults to the number of physical cores (and will fall back to
thread::hardware_concurrency otherwise). This avoid oversubscribing
the physical cores using hyperthreading.
Reviewers: mehdi_amini, pcc
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D25775
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@284618 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed