Intel's Clear Linux

[haarp]

Recently, Clear Linux has been in the news. Supposedly it's a custom distro made by Intel with advanced features and optimization. The showcased benchmarks do indicate a decent speed boost. Fedora appears to be interested in porting some of that (https://lists.fedoraproject.org/archives/list/devel@lists.fedoraproject.org/thread/UXTL3INISMOIVYI4JOYVHCEOFLMFC7CO/)

[rice alert] Naturally, as a Gentoo user I also want a piece of that cake! [/rice alert]

Seeing as this is Intel instead of some ricer's half-broken Gentoo, Intel's work could very well benfit other distros. The official site is rather low on information as to just what they're actually doing tho. Here's what I gathered so far:

- Custom patches
- Likely using ICC as their compiler (not sure) (likely the source of most of the performance boost, as long as you use an Intel CPU) Nope.
- Use -O3 where possible
- Automatic pgo (https://clearlinux.org/features/autofdo)
- Function Multiversioning (https://clearlinux.org/features/function-multiversioning-fmv) - probably not of interest for Gentoo users

I can't find any patches or any easily discoverable sources at all, which is unfortunate. Or maybe I haven't looked in the right places.


Anyway. Has anyone given it a try or found something interesting?

[axl]

it was never official, but then again what could be official in gentoo world... i tried to use icc back in 2006-2007. some packs dont compile with it. some do.

back then, my main focus was php. and it did compile with icc, and it did work generally 10-15% faster compiled with gcc.

but also had random behavior. and was virtually undebuggable.

i get why intel is trying to make their own distro. but also, gcc has matured a lot since then. and the right way to do things for intel would be to contribute to gcc, rather then make their own distro. or compiler. bleah. now i stay away from it as much as i can.

rather have systems that dont need that extra 10% umph.

EDIT: i mean really... if you were making processors, would you make your own compiler, or would you contribute to gcc? intel is yet again, taking the wrong turn. but they will bounce back. they always do.

[Chrishas]

The sources for the packages are inside the corresponding directory(current/release/latest):

https://download.clearlinux.org/

I have a VM with the live version but not sure how to check if icc was used.
I tried strings and readelf on some binaries and libraries but didn't see anything with icc, perhaps someone else can provide more info.

The below post says GCC was used:
https://clearlinux.org/blogs/performance-race
Mostly it seems to involve more aggressive compiler flags which other distros may avoid for stability or other reasons.

[chithanh]

[kernelOfTruth]

Looks like they do per-package optimizations on top of all the other optimization goodness:

http://www.phoronix.com/scan.php?page=article&item=intel-clr-opengl&num=1
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Hardcore Gentoo Linux user since 2004

[krinn]

[chithanh]

For both gcc and icc, -O3 is the highest optimization level.
According to the description on the Intel website, the difference between -O2 and -O3 is mostly in loop optimization/transformation, which is comparable to what gcc does. icc does seem to do some vectorization at -O2 which gcc does only at -O3 though.

[krinn]

thanks chithanh, that no-prec-div might do wonders!

[haarp]

Ah. According to Moronix, they were using GCC 5.3 all along (but switched to GCC6 now). So they must indeed have some interesting patches.