Clang LTO Support For The Linux Kernel Spun Up A Seventh Time

[phoronix]

Phoronix: Clang LTO Support For The Linux Kernel Spun Up A Seventh Time

Google engineers have sent out their latest patches for allowing the mainline Linux kernel to be built with LLVM Clang link-time optimizations (LTO) for greater performance and possibly size benefits...

http://www.phoronix.com/scan.php?page=news_item&px=Clang-LTO-Linux-v7

[CochainComplex]

Good news. I wondering how much more work is needed to make LTOing possible with the GCC. I know that there was some patch set floating around but AFAIK it is not usable anymore?

[Ub42]

A Microsoft employee did some kernel LTO+PGO benchmark with GCC 9.2.1. You can find his slides from the last Linux plumbers here

[ms178]

By the way, if you want to try out the most recent patchset on x86, just visit his github repo and download the sources from the clang-lto branch. It compiled fine for me, just be sure to not have the "Trim unused/obsolete symbols" option enabled as it would blow up with a lot of modprobe issues then.

[CochainComplex]

A Microsoft employee did some kernel LTO+PGO benchmark with GCC 9.2.1. You can find his slides from the last Linux plumbers here

Thx! I remember but I thought he did it with Clang.

[darkbasic]

"Google notes they have used a Clang LTO+CFI build for their Linux kernel on "millions of Pixel devices" with Android since 2018."

It doesn't matter how many millions or billions, anything but -O2 will always be unstable for mainline kernel developers.

[r08z]

Thank you but I'll stick with GCC and -O2.

[brad0]

Just say no to GCC.

[aspen]

Thank you but I'll stick with GCC and -O2.

Any actual reason why?