Ubuntu 21.04 Moves Ahead With Enabling LTO Optimizations For Greater Performance

[schmidtbag]

No, you're thinking of the x86_64_v2 and x86_64_v3 proposals other distributions are discussing. Those both raise the minimum CPU levels to approximately Nehalem for v2 and Skylake/Zen for v3. Red Hat is thinking of v2 and Arch v3.

Yup that seems to be the case.

[ehansin]

Mandriva enable LTO few Yeats ago.

Are there other Yeats? I am only familiar with William Butler.

Sorry, I couldn't help myself. I promise not to be part of the typo or grammar patrol, it just made me chuckle when I thought about it.

[F.Ultra]

yes, but they have daily builds and i wanted to know if it was llive.

http://www.cdimage.ubuntu.com/daily-live/current/

edit: I now see that your real question was if LTO has been enabled in the binaries built for 21.04 and for that I have no idea, sorry.
edit2: Looked some more into this and no, there are not LOT built binaries yet, this is just enabling dpkg-buildpackage to build with LTO enabled if you build/rebuild a package but no such rebuilt packages have as of yet been pushed into the deb repository.

[smitty3268]

IIRC, this limits what CPUs you can use, right?

LTO allows the compiler to optimize across multiple files at the same time, rather than treating each .c or .cpp file as completely separate. That can allow the compiler to do quite a number of things that are smarter, but the primary difference it makes is allowing it to strip out unused code that it couldn't before.

That's really all it does. There's no difference to who can run the resulting executables or how things get installed.

[skeevy420]

IIRC, this limits what CPUs you can use, right? Seems like this is a bit of a mistake for Ubuntu to follow. It'd be fine for some derivative but not the main OS.

Not that long ago there was the discussion of ditching 32 bit support too. Ubuntu to me should be more focused on compatibility than performance. Not that any of it matters to me - I don't use Ubuntu, or legacy hardware.

No, you're thinking of the x86_64_v2 and x86_64_v3 proposals other distributions are discussing. Those both raise the minimum CPU levels to approximately Nehalem for v2 and Skylake/Zen for v3. Red Hat is thinking of v2 and Arch v3.

To put that in perspective, and I'm making 2.5 up here, Clear Linux is optimized for 2.5 to 3 -- Built for Sandy Bridge, AVX gen 1 in-between Nehelam and Skylake, but will use AVX2/Skylake-compatible optimizations if running on compatible CPUs -- -march=sandybridge -mtune=skylake.

I've just thought of this -- Will -march=x86_64_v1 -mtune=x86_64_v3 produce legacy compatible binaries that will let modern CPUs fly? Essentially Generic Clear.

[LightBit]

IIRC, this limits what CPUs you can use, right?

No. I don't see any reason for that.

[schmidtbag]

IIRC, this limits what CPUs you can use, right? Seems like this is a bit of a mistake for Ubuntu to follow. It'd be fine for some derivative but not the main OS.

Not that long ago there was the discussion of ditching 32 bit support too. Ubuntu to me should be more focused on compatibility than performance. Not that any of it matters to me - I don't use Ubuntu, or legacy hardware.

[sireangelus]

ubuntu 21.04, as the name suggests, is released in April 2021

yes, but they have daily builds and i wanted to know if it was llive.

[CochainComplex]

Waiting for the popos spin

[ms178]

I've tried Kubuntu daily yesterday. I saw a major regression though for my system (of 10 FPS in Company of Heroes 2 - from 75 to 65 FPS), but I've tried out the new LLVM12 RC3 and compiled 5.12 RC3 with Clang and LTO, maybe it was due to not running the Xanmod Kernel sources there. I certainly will revisit this once 21.04 is released.