More Sandy Bridge Scheduling Updates For LLVM

[phoronix]

Phoronix: More Sandy Bridge Scheduling Updates For LLVM

Intel engineers continue tuning the Sandy Bridge scheduler information within the LLVM compiler infrastructure...

http://www.phoronix.com/scan.php?page=news_item&px=Intel-More-SNB-Tuning-LLVM

[Ray54]

I have 2 Sandy Bridge computers, an i3 and a Pentium, so could someone please explain what is the likely performance improvement when using Mint 18 for Firefox, playing games or Java compiling. I realize this is for LLVM and most older programs were probably compiled with GCC. If it is negligible, then why would Intel spend money on doing this, are they still selling Sandy Bridge into certain markets or do they have maintenance obligations/contracts.

[Gusar]

@Ray54: I think this is like the SNA situation in the intel DDX driver, where SNA stands for "Sandy Bridge New Acceleration", but it actually supports everything from gen3 to gen9 (Sandy Bridge is gen6). So this is likely just the beginning of something that will, similarly to SNA, cover all Intel CPUs.

As for performance improvements, well, Firefox's new CSS engine, Stylo, is compiled with LLVM/clang, and with how bloated today's web is, every improvement to a web engine can help. That's just one example, I'm sure other people can come up with more.

[microcode]

I have 2 Sandy Bridge computers, an i3 and a Pentium, so could someone please explain what is the likely performance improvement when using Mint 18 for Firefox, playing games or Java compiling. I realize this is for LLVM and most older programs were probably compiled with GCC. If it is negligible, then why would Intel spend money on doing this, are they still selling Sandy Bridge into certain markets or do they have maintenance obligations/contracts.

@Ray54: I think this is like the SNA situation in the intel DDX driver, where SNA stands for "Sandy Bridge New Acceleration", but it actually supports everything from gen3 to gen9 (Sandy Bridge is gen6). So this is likely just the beginning of something that will, similarly to SNA, cover all Intel CPUs.

As for performance improvements, well, Firefox's new CSS engine, Stylo, is compiled with LLVM/clang, and with how bloated today's web is, every improvement to a web engine can help. That's just one example, I'm sure other people can come up with more.

Well, in this case it would only affect software compiled with LLVM with flags turned on to tune for Sandybridge. So the answer is: it will likely have no effect on any software you use.

As for why they're doing this, Sandybridge is still widely deployed in cloud computing installments, and many users of cloud computing resources know ahead of time that they'll be running their software on a Sandybridge. I suspect they're doing this as ongoing support for their Xeon customers.

[eigenlambda]

Getting each individual thing right isn't necessarily useful, but having the infrastructure to get everything right often is.

[timofonic]

Despite that LLVM can't compete in terms of optimization with GCC. I really hope Mozilla gets sane and sponsors full Rust support in GCC.

I hope someday libgccjit improves to the level of being able to be a replacement for drivers like AMD gfx and such, I think there's need of competition and more diversity even if it "only" means two compiler infrastructures would be able to do the same.