[llvm-dev] LTO query

[Teresa Johnson via llvm-dev]

Hopefully someone else on the dev list who has experience with LNT and the
LLVM test-suite will chime in. I've never run it myself. Adding Mehdi since
he ran it with LTO/ThinLTO.

I found some documentation for the test-suite:
https://llvm.org/docs/TestingGuide.html#test-suite-overview
http://llvm.org/docs/lnt/quickstart.html
http://llvm.org/docs/lnt/tests.html#llvm-cmake-test-suite

But I can't find any documentation describing how to pass custom options to
lnt runtests, so hopefully Mehdi or someone else can help.

Teresa

On Fri, May 11, 2018 at 7:59 AM Siddharth Shankar Swain <
h2015096 at pilani.bits-pilani.ac.in> wrote:

> Yes running LLVM performance test suite with LTO and Thin LTO enabled.
> Thanks,
> Siddharth
>
> On Fri, May 11, 2018 at 7:32 PM, Teresa Johnson <tejohnson at google.com>
> wrote:
>
>> I'm not completely sure what you are asking. Are you looking for
>> performance benchmarks to use for LTO and ThinLTO testing? Or are you
>> asking how to build/run with LTO and ThinLTO? Are you asking how to run
>> LLVM's performance test-suite with LTO and ThinLTO?
>>
>> Teresa
>>
>> On Fri, May 11, 2018 at 5:21 AM Siddharth Shankar Swain <
>> h2015096 at pilani.bits-pilani.ac.in> wrote:
>>
>>> Hi,
>>> Thanks for the info, If i only want to run performance test on
>>> benchmarks for LTO and Thin LTO enabled target, Can u suggest ways to do it
>>> ? I want to do it at my end.
>>> Thanks,
>>> Siddharth
>>>
>>> On Wed, May 2, 2018 at 7:03 PM, Teresa Johnson <tejohnson at google.com>
>>> wrote:
>>>
>>>> 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
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> LLVM Developers mailing list
>>>>> llvm-dev at lists.llvm.org
>>>>> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>>>>>
>>>>>
>>>>
>>>>
>>>> --
>>>> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
>>>>  408-460-2413
>>>>
>>>
>>>
>>
>> --
>> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
>>  408-460-2413
>>
>
>

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