[llvm-dev] LTO query

[Teresa Johnson via llvm-dev]

I've only measured performance on x86. There are some old results for SPEC
cpu2006 in the blog post here:
   http://blog.llvm.org/2016/06/thinlto-scalable-and-incremental-lto.html
The benefit is benchmark dependent, e.g. small benchmarks often don't
improve much as they don't require whole program optimizations.

We've improved the ThinLTO optimizations since then, but I don't have any
current numbers for SPEC handy.

Note that the performance is higher if you combine with PGO as the two
techniques are complementary. I would say 5-10% improvement is pretty
common (when measured on top of PGO), for codes that can benefit from whole
program / cross-module optimizations.

Teresa

On Tue, May 1, 2018 at 12:12 PM, Siddharth Shankar Swain via llvm-dev <
llvm-dev at lists.llvm.org> wrote:

> Hi all,
> We have enabled Thin LTO and LTO for a specific target architecture. What
> can be the possible scopes of improvement depending on the target  after we
> enable the basic LTO and thin LTO.?
> Thanks,
> Siddharth
>
>
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>


-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
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