But now include a check for CPU_COUNT so we still build on 10 year old
versions of glibc.
Original message:
Use sched_getaffinity instead of std:🧵:hardware_concurrency.
The issue with std:🧵:hardware_concurrency is that it forwards
to libc and some implementations (like glibc) don't take thread
affinity into consideration.
With this change a llvm program that can execute in only 2 cores will
use 2 threads, even if the machine has 32 cores.
This makes benchmarking a lot easier, but should also help if someone
doesn't want to use all cores for compilation for example.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314931 91177308-0d34-0410-b5e6-96231b3b80d8
Summary:
This reverts D38481. The change breaks systems with older versions of glibc. It
injects a use of CPU_COUNT() from sched.h without checking to ensure that the
function exists first.
Reviewers:
Subscribers:
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314922 91177308-0d34-0410-b5e6-96231b3b80d8
The issue with std:🧵:hardware_concurrency is that it forwards
to libc and some implementations (like glibc) don't take thread
affinity into consideration.
With this change a llvm program that can execute in only 2 cores will
use 2 threads, even if the machine has 32 cores.
This makes benchmarking a lot easier, but should also help if someone
doesn't want to use all cores for compilation for example.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@314809 91177308-0d34-0410-b5e6-96231b3b80d8
This time it actually occurred to me to change the #defines
to actually test the pre-processed out codepath. Hopefully
this time it works.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@302752 91177308-0d34-0410-b5e6-96231b3b80d8
