[llvm-dev] RFC: A binary serialization format for MemProf

[Teresa Johnson via llvm-dev]

+Than McIntosh <thanm at google.com> again to comment on the gc question below.

On Mon, Oct 4, 2021 at 2:38 AM Andrey Bokhanko <andreybokhanko at gmail.com>
wrote:

> Thanks Teresa and others for the clarification!
>
> On Fri, Oct 1, 2021 at 8:32 PM Teresa Johnson <tejohnson at google.com>
> wrote:
>
>> I was going to respond similarly, and add a note that it isn't clear that
>> gollvm (LLVM-based Go compiler) supports either PGO or the sanitizers, so
>> that may be more difficult than Rust which does. As Snehasish notes, we are
>> focused on C/C++, but this will all be done in the LLVM IR level and should
>> be language independent in theory.
>>
>
> Let me note that I specifically meant gc (Google's standard Go compiler),
> not gollvm. IMHO, there is an intrinsic value of data formats being unified
> among different toolchains -- as very well demonstrated by DWARF.
>
> (Yes, I'm aware that gc doesn't support even ages-long instruction
> profiling. One of the reasons is the apparent lack of implemented
> optimizations that can directly benefit from profiling. In case of memory
> profiling, the use case is clear. Also, given that BOLT helps Go a lot (up
> to +20% speed-up on our internal tests), I expect the same for memory
> profiling, which will warrant extending gc capabilities to use MemProf
> format.)
>

I don't think the gc compiler even involves llvm as it is written in Go. So
that's definitely outside the scope of our work. I'm not personally very
familiar with Go compiler toolchains and their roadmaps, but Than can
probably comment.

Teresa


> Yours,
> Andrey
>
>
>> Teresa
>>
>> On Fri, Oct 1, 2021 at 10:25 AM Snehasish Kumar <snehasishk at google.com>
>> wrote:
>>
>>> Hi Andrey,
>>>
>>> The serialization format is language independent, though our focus is
>>> C/C++. Note that our instrumentation is based on the LLVM sanitizer
>>> infrastructure and should work for Rust (supports building with sanitizers
>>> [1]). We have not considered using the data profile for non-C/C++ codes.
>>>
>>> Regards,
>>> Snehasish
>>>
>>> [1]
>>> https://doc.rust-lang.org/beta/unstable-book/compiler-flags/sanitizer.html
>>>
>>> On Fri, Oct 1, 2021 at 9:14 AM Andrey Bokhanko <andreybokhanko at gmail.com>
>>> wrote:
>>>
>>>> Hi Snehasish, David and Theresa,
>>>>
>>>> I'm really glad to see the steady progress in this area!
>>>>
>>>> It looks like the format is pretty much language independent
>>>> (correct?) -- so it can be applied not only to C/C++, but other
>>>> languages (Rust) and even toolchains (Go) as well? If you have already
>>>> considered using data profile for non-C/C++, may I kindly ask you to
>>>> share your thoughts on this?
>>>>
>>>> Yours,
>>>> Andrey
>>>> ===
>>>> Advanced Software Technology Lab
>>>> Huawei
>>>>
>>>> On Thu, Sep 30, 2021 at 1:17 AM Snehasish Kumar <snehasishk at google.com>
>>>> wrote:
>>>> >
>>>>
>>>
>>
>> --
>> Teresa Johnson |  Software Engineer |  tejohnson at google.com |
>>
>

-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |
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